Vorshlag C5 & C6 Corvette Development + NewBalance and Rampage

[Fair!]

continued from above

Since this was a Sunday and we had seen so much traffic on track at the last member day we aimed to get there around 11:30, hoping to get on track before the 12:30 lunch break. Which almost happened, but we got out on track at 12:30-1 pm and again in another session at 2:00-2:30 pm. Between Amy and I we made 23 hot laps this time, without any brake overheating issues. Now we still had brake problems, but that was all a rear lockup situation. That ABS was wigging out any time either of us braked over 1.0 g.



We saw accelerometer data of around 1.15g (both lateral and braking gs) but the rear tires would lock up quickly in stops over 1.0g, then the car tried to swap ends. Amy (a much smoother driver than me) saw the same issues, so we both had to dial back our braking considerably, especially when compared to other cars we have tracked in the past. Now we might have a sticky caliper piston, or some other mechanical issue - so we are preemptively changing ALL of the calipers and rotors in the next round of mods. I have felt Ice Mode / ABS issues on virtually every GM car I have ever driven on track, including multiple C4/5/6 Corvettes and 5th gen Camaros, so it might just be this issue.



The video above has more data channels from the CAN data stream, logged via the AiM Solo after I properly uploaded a new firmware versions specifically for the C6. Everything worked except the Steering Wheel Position Sensor. In fact this sensor often breaks on many C5 and C6 cars, so we think this happened - we got a "Service Active Handling" fault at both events. As always drove with both the traction control and active handling control systems turned off, as it is faster on virtually every OEM car than leaving the electronic nannies on.



We met our friend Jerry out at the track and I chased him for a bit in his C7 Z06, but he was several seconds a lap faster, so I didn't chase him long. It was supposed to rain all day but didn't, and the 63°F ambient temp was perfect. We even saw rainbows in the clouds.



This time we stuck around longer and drove in 2 different track sessions. My first stint was just 2 laps, to scrub the brand new tires and get them up to temp, and I quickly came in to let Amy bleed the tires down to 33F/31R hot. The understeer was still there but not as pronounced as on the 245/275 All Seasons. There was a LOT of traffic and I was one of the slower folks on track, so I had a lot of aborted fast laps to get out of people's way - and of course a few close calls where the rear tires locked into the big braking zones (T3 and T9 - see track map below). In my second stint in session 1 I made 5 laps and managed a 1:26.428. Then we swapped Amy in for 4 hot laps where I coached.

We had an hour to kill before our next session where we could go out and we relaxed a bit and Amy and I talked about her comfort level in the car. We made some seat position changes before going out again. Traffic was much lower in session 2 and I went out for an 8 lap stint, running two other 1.26.9 laps back to back. I had a high 1:25 lap on predictive timing while chasing Jerry's C7Z, but a 1.1g stop into T3 nearly sent me off track backwards, so I reset and went for one last blast the next lap - finding another couple of tenths with a 1:26.248 best.

Amy then went out next for a 5 lap stint where I didn't ride with her, and she had virtually zero traffic - which helped her get into a groove where she dropped TEN seconds from her best laps back on April 9th! She came in beaming, knowing that she was much faster this time. And more importantly, she had a lot of fun - which was the point of this C6 purchase: to get some track time while our other cars are being built and to have a ball doing it.



While the rear tire lock up issues were unnerving they were not completely unexpected. At least the G-LOC pads never got so hot that the fluid boiled and we never had a long pedal, always had good pad bite - but perhaps too much for this ABS systems. Not a huge problem, and if this persists after the next set of brake upgrades, we have another couple of ABS systems we can swap onto this car. Was hoping we could avoid that, we will see.

"INTERIM" WHEELS ORDERED (TWICE)

Remember the "one mistake" I mentioned in the 19x10 wheel and Hankook tire order we made after Track Test #1? Well it was the fact that I did NOT order black wheels, but that's what they sent. And I absolutely HATE black wheels - they disappear and you cannot see what they look like. Just a mass of black.



I mentioned this to my TR rep and he admitted the error, then sold me another set of these 19x10s in the correct silver color, above. Luckily these were still on closeout and again super inexpensive, plus at I got free shipping this time. I also found some TPMS sensors elsewhere and had the 275 Hankook tires swapped to these silver wheels after just that one event.



Not a great pic but it was raining all week and that's the best I have for now. Long term these will likely be the "street wheels" we use to drive around on, after these RS-4s have either worn out or heat cycled out. The "real" wheels we custom ordered 6 weeks ago are almost done, and those will be used exclusively for track/autocross use. More on that next time.



Meanwhile the ugly black wheels will now be getting a set of new Hoosier R7s, which I picked up for a song (old date codes, but stored inside and never mounted so they still have the mold release). The Hoosiers won't go on the car until we have the MCS coilovers on, and then we will test that setup with the 275 RS-4s first and the 295 Hoosiers on identical wheels on the same day. Just couldn't pass up this deal, and its more data in my long term 200TW vs R-compound tire lap comparison testing - which we did extensively for 2 seasons of NASA TT events in our 2018 Mustang in TT2 and TT3 (2018-2019).

LAP TIMES LIST RANKING AT MSR-C 1.7

Here is my "leader board" list for laps at Motorsport Ranch Cresson on their 1.7 mile CCW course, and the first two track tests on the C6 are shown ranked inside my videos/times for other cars I've driven here.




Love this track and have been coming here for 20 years. Their 1.7 mile course (see above) is relatively easy to learn, has a good mix of corners, and is short enough to not have a long out lap and in lap - making for more laps in a 30 minute session. This facility has had consistent paving from when they opened in 2000 until they repaved in 2021 - a month before the recent repave, NASA drivers were still setting new lap records on the "old" asphalt. Having driven before and after the repave, there is no significant change and lap times didn't change - not something you can say for most tracks over 2 plus decades of use.



We have used this course for setup and testing, and I personally have driven over 500 laps in many different cars here. With this much seat time at the same track I can drive fairly consistent laps, in the same conditions. In the past I have done as many as 15 track tests / competition weekends in a single year on this same 1.7 CCW configuration. MSR has 4 configurations: 1.7 CCW. 1.7 CW, 1.3 mile (see above) and the 3.1 mile layout (combines 1.7 and 1.3 together). We finally got a membership earlier in 2021 so we can do even more testing here. The only track I have more laps at is Eagles Canyon (above right), but they repaved recently and reconfigured (from 2.9 to 3.1 mile) about a year ago, so none of my old laps there are relevant to compare to for current testing. Plus their new 3.1 mile course is a bit long for a small number of laps driven in a given stint - with long out- and in-laps.



I keep this list updated of my best laps at this track in various cars I have driven, and put this list into most project build threads to show how a particular car is progressing, compared to other cars driven by the same driver - me. Why just my times? Well simply put it keeps the "driver variables" to a minimum.

I am not claiming to be a great driver by showing "my list" of laps only - far from it, I know I'm a hack - but I have driven 50+ cars at this track and have set 5 or 6 NASA Time Trial lap records here. As "terrible" of a driver as I may be, my laps here tend to be fairly consistent when the tires/brakes/traffic line up, often running multiple laps in a row in the same tenth of a second. That consistency can at least help show a progression of performance for a car over different rounds of modifications driven at different times, even if my times aren't the absolute best that a given car could theoretically do.

This list of laps shows a spread of times for a range of cars under similar conditions, with both 200TW and Hoosier race tires, as noted. Each time we add a new Track Test for this C6 I will add it in bold into this ranked lap time list:

• 2013 Scion FR-S, Baseline Stock Lap Time, 215mm tires (Test #1), 8/31/16: 1:31.90
• 2006 Corvette, Baseline Stock Lap Time, 245/275 all season tires (Test #1), 4/9/21: 1:28.743
• 2016 Focus RS, baseline stock laps, 235mm MPSS, 6/15/16: 1:27.40
• 2006 Corvette, G-LOC R12/R10 pads, 275 Hankook RS-4 tires (Test #2), 4/18/21: 1:26.248
• 2013 Scion FR-S, AST 5100s, camber, bars, BBK, "not fresh" 315mm Rival-S tires (Test #6), 8/25/18: 1:25.978
• 2001 BMW 330i, NASA TTD prepped, 216 whp, MCS coilovers, camber, 245 Hoosier R7, 3/12/17: 1:23.789
• 2016 Focus RS, coilovers and camber, 275mm RE-71R, (Test #4) 9/27/16: 1:23.658
• 2012 Corvette C6 Z06, Carbotech XP10/XP8 pads, 285/335 MPSS, perf alignment, 9/16/16: 1:22.63
• 2013 Camaro SS 1LE, 305 Hankook RS-3, Bilstein PSS, camber, seats, brake ducting, 430whp, 9/16/16: 1:22.56
• 1992 Corvette, NASA TTC prepped, LT1, 288 whp, stock shocks, Hyperco springs, 245 R7s, 3/13/16: 1:21.90
• 2017 Corvette Grand Sport, Z07 aero package, 285/335 MPSS, perf alignment, 9/16/16: 1:21.89
• 2018 Mustang GT, "sort of" TT3 prepped, 305 RE-71R street tires, 474 whp, 3/10/19: 1:20.348
• 2018 Mustang GT, "mostly" TT3 prepped, 315 Hoosier R7, 474 whp, 3/10/19: 1:19.2
• 2011 Mustang GT, NASA TT3 prepped, 335/345 Hoosier A7, 447 whp, aero, 3802 lbs, 3/9/14: 1:17.310

This C6 is actually a bit slower than we expected, when compared to the red target times above - a nearly stock C6 Z06 and a C7 GS Corvettes that I drove on the same day. Both the C6Z and C7 GS had performance alignments and much wider OEM tires, so that explains some of this deficit - but not all. In the next post we will have more lap testing on our C6, hopefully moving this car's best time up the leader board - eventually ahead of the Spec Miata track record! #LapTimesMatter

PERFORMANCE ALIGNMENT

This is something we recommend for anyone to do to their car BEFORE they ever go do their first track event in any given car. The goal for most unmodified cars you want to autocross or track is to add as much negative camber the stock adjustment range allows - because the stock suspension will allow a LOT more body roll than one with a modified suspension. And excess roll allows the tires to wear abnormally fast on the outer shoulders. Adding static negative camber will mitigate this, of course.


The first autocross in our 2018 GT shredded the OEM tires. Look at that roll! With coilovers/springs/camber it wore the tires GREAT

We had intended to add a Performance Alignment to this C6 between Track Tests 1 and 2, to show that as part of the lap time progression. Why wait? I wanted the Baseline Stock track test to be the absolute "stockest of stock" for this base model C6, and also why we did that one with the all season tires and random brake pads (but with good brake fluid and oil - I'm not suicidal). As you can see (below left) the C6 had tons of body roll, even on low grip 245/275 all season tires.



Well timing didn't work out for this to happen until after Track Test #2. Since we moved our shop "out to the country" in 2018 we have been looking for a place nearby with a proper laser alignment rack. We don't own one of these $75-100K alignment racks and it's unlikely we will - because they would never pay for themselves. In our best months we had maybe 3-4 cars aligned using a partner shop (that little use would never pay the note on these machines). At our last shop location we had a nearby shop with a really nice alignment rack and we would take cars there with a list of measurements we wanted. After a while we had trained their crew to do performance alignments to our specs. I was "breaking in a new shop" the week before Track Test #2...


As a test for a new nearby shop, I had taken my shop truck (above) to check out their abilities on a state of the art alignment rig, and they did a great job. They do 10-12 alignments per day, but on the only open slot we had for the C6 (the day before Track Test #2) they were slammed and couldn't fit us in, so we did BOTH first tests on the crappy stock alignment. That hurt lap times, for sure.



Looking at the car in stock form (above) we could see that the alignment was as Plain Jane as the rest of the car - it never had a performance alignment, and this is likely as it came from GM sixteen years ago. After we finally got the car aligned we can see the "before" settings were pretty bad: -0.6°/-0.8° camber front and -0.4°/-.6° camber rear. Oof...



They hit the marks we set for them, but it took them longer to do than they expected. These Corvettes require a lot of shimming on the front suspension to get the camber set. At least track test #3 (later this week!) will have some proper camber, and that alone will help lap times. We will likely dial in more rear camber on the next alignment as well (there are two mods planned in the future that will require new alignments).

WHAT'S NEXT?

We have a LOT of things ordered for future rounds of modifications and subsequent track tests. If I have to go to the track once a week to test all of these, well darn, I guess I will do it!



Brad is in the middle of swapping all of the calipers and rotors for the larger (and different hydraulic piston sized) Z51 bits, shown above. Also the DeWitt radiator, new hoses, lower radiator support (old one is smashed), and more. We should be back on track later this week to see if this makes for any changes in Test # 3.



There are more planned upgrade parts already here or en route, but those will be for later rounds of mods. The MCS dampers coupled with real spring rates should make a substantial change in handling - and might even help with the rear brake locking situation (old dampers and springs allowing too much rear rise/brake dive?) We will see in the next track test if the Z51 rear caliper hydraulic changes help that situation. We can always "dumb down" the rear brakes by swapping in some really crap rear pads, too. Stay tuned for more!

Thanks for reading,

Terry @ Vorshlag

[Ando]

Terry and Vorshlag Team,
A couple of observations from corvette track cars over the years, I know you guys know most of this stuff already, but it bears repeating....

Suspension Bushings are crazy soft on the Vette and only poorly control camber especially once you get a really good tire on there. Delrin kits are available from a couple of suppliers and make a noticeable improvement in feel and control of the contact patch. Bearing kits are available but expensive. Polyurethane is also available, but with the obvious drawbacks....

Corvette Control Arm camber eccentrics are notorious for slipping, especially on good tires or when torqued to only the factory torque spec like an alignment shop is likely to do... Either crank down on those things or better yet switch to a "camber plate" system that locks out the lower bolts and adjusts alignment using shims on your upper control arms. Added benefit of making alignment adjustments with minimal toe change. A slipped eccentric will really ruin your day....

The oem single sided C clamp type brake calipers will always taper the pads, necessitating flips and rotations, but eventually the soft aluminum calipers will actually spread and wear very unevenly from top to bottom. The sooner you switch to a fixed caliper system the sooner you can save on pad costs. There are a few fixed caliper systems that use the stock cheap rotors, allowing for frequent inexpensive rotor changes.

Corvette brake force is electronically distributed. It seems to have a heavy natural rear bias and electronically reduces rear pressure. This is just one more aspect of the overall weirdness of gm brake systems, but there might be improvements to be made by upgrading only the front to add some natural bias especially with a square wheel set up.

The clutch throwout bearing slave system holds a ton of heat and cooks the fluid, suck out and refill the reservoir often. The oem clutch master cylinder has a lot of problems, adapting to an after market tilton or similar removes the return spring system and makes for a more natural clutch feel and to prevent a sticking clutch pedal.

Like with your engine oil, replace the power steering fluid with a quality ester based synthetic like Redline, or maybe Motul makes one?

Vent the hood to get enough airflow, add ducting to the front brakes, add oil cooling, you can see heat is already going to be an issue when the temps go up, after that start watching your trans temps.


Finally Thanks for all the great content and posts!

[Fair!]

Project Update for April 11, 2022: It has been an eternity since I updated this project build thread - eleven months! - but the shop has been super slammed and I am behind on all of my forum build thread updates, videos, blog posts, and the rest. Since May of 2021 we have done three more track tests in this Corvette, following lots of suspension, brake, and safety upgrades. Since last April we have upgraded the base brakes it to Z51 spec, swapped in a Mk60 ABS system, swapped in new hubs and studs, upgraded to a massive aluminum radiator, made custom seat brackets, added aftermarket seats, added a harness bar and harnesses, installed a carbon splitter lip, upgraded the power steering cooler, performed 9 ABS tests, then swapped in MCS remote double adjustable coilovers. Whew!



The stock braking system fought us for most of the last year, and we often tried things that did not work - some of it from "conventional internet advice", then other things we tried on our own. Massive changes were made, with more still to come.



In addition to all of these changes and upgrades, one stupid mistake slipped through - which changed the "balance" in Project New Balance, and handicapped lap times on track tests #3 through #5. Live and learn, I guess. Over several months of work many hundreds of pictures and videos were taken, and I want to share that with you - but it will take several forum installments to get all of that published. Each one of these forum updates takes me 6-8 hours to write & edit, plus many more hours of photo and video editing. Please be patient as I try to dig out of a massive "forum post" backlog on this project and a half dozen others I try to chronicle. We will share all we have learned, the good so keep tuning in. Let's get started!

BRAKE UPGRADE - JL9 (BASE) TO J55 (Z51)

This narrow body C6 had the worst possible brakes of many offered on the C6 from 2005-2014, and we aimed to make the next logical upgrade - to the Z51 option's "J55" brakes (we will just call them Z51 brakes to make it simpler). I purchased new rotors from Raybestos and calipers from Centric and AC Delco. Strangely there was only one front Z51 front caliper available from Rock Auto at the time, but the calipers were identical on JL9 to Z51 - the only change was in the Z51 brackets, which I found on RA also. These move the same caliper "out" to work with the larger diameter rotors.



We looked at LOTS of other brake upgrade options before going this Z51 route, and honestly the "Z51 upgrade kit" I found on eBay (below left) might have easier - but I still wanted fresh calipers. I also looked at countless other options including C6 Grand Sport/Z06 brakes, AP brakes, Wilwood brakes, and more. I wasted several hours and stewed on this decision for days, but ultimately I went with the budget "RockAuto" Z51 upgrade - to show that maybe, just maybe - you don't need to spend several thousand bucks to make a Corvette stop. This is a rather light car (3100) compared to the normal 3600 pound street car Mustangs we build.



The JL9 option code included dainty little rotors on both ends that we replaced with the larger OEM spec Z51 units, shown below. The Z51 rotors were not only larger in diameter, they were cross drilled. Now I wouldn't have bought drilled rotors, but that is how most of the replacements come, and how the factory did it. Of course you don't NEED cross drilled rotors, as it is simply a holdover from poor brake pad techniques (degassing) from the 1980s, and the OEM's did them for decades longer because it "looked cool".



This Z51 upgrade was done in May 2021 when we were still chasing the weird brake bias / rear lockup issues on the car. We'd only done the first two track tests and were hoping we could "trick" the known-to-suck GM Anti-lock Brake System programming into... sucking less. Lots of suggestions were made online about brake pad compounds, tire heights, rotor sizes - some of the many things were known to trip up the factory ABS. We tested all of those and more, and none of them fixed THIS particular car, which had serious rear lockup unless we crippled the grip level to 500 treadware tires (I will cover much of this testing in a later forum installment).



As hot as we got the brakes in the first track test, as poorly as they worked, and as old as these parts were, I felt it was a good idea to replace the old calipers and rotors. And I had hoped to get the braking to work as well as it had on our 2005 Z51, which I autocrossed several times and never had it lock the rear brakes up. So I chased down new PBR twin piston front calipers and the mating Z51 caliper brackets, which spaced them "up" to deal with the larger diameter rotors.



Now the larger brakes would come with a weight penalty, but that is to be expected. The Raybestos branded 13.4" dia Z51 fronts were 23.3 pounds and the (admittedly worn) JL9 12.8" dia rotors were 19.6, for an increase of about 7 pounds for both fronts.



The delta on the rear rotors was worse because the diameter jump was larger, going from 12.0" dia to 13.0", and the weight jumped from 15.0 to 20.7 pounds, a nearly 11 pound increase. But more importantly, this larger diameter change would likely make the rear bias issues worse - and it did, once we tested on track. We needed to ditch this base car's crappy ABS in any case, which we did (and I'll show next time). After the Mk60 ABS swap the brakes work GREAT!



The front "upgrade" was pretty simple. Remove the caliper and bracket, swap to the bigger rotors, then the new Z51 spec brackets went on, then the calipers and pads. On one side we re-used the base caliper temporarily, simply because none were available at the time. This was swapped out about a month later and had zero effect on performance.



The rear was the same, only you might have to retract the rear parking brake drum brake shoes to get the old rotor off. There was one new hub on this car, changed by the prior owner right before we bought the car. The Z51 rear brakes were installed without issue and the same G-LOC pads (R12 front / R10 rear) were reinstalled.

REAR FENDER LINER REPLACEMENT



A seemingly small item, the left rear fender liner was all busted to hell on this car when I bought it. I think a previous owner had a blowout and it tore this liner up, and it had some extra screws and "zip tie surgery" holding it together. I found a good one on eBay for $68 and ordered it (it would have been a lot more and many pieces to get it from GM.)



The rear fender liner is a larger assembly and includes the factory rear brake cooling within it. When Brad was doing the brake upgrades he swapped in this used but good fender liner and replaced the old busted unit.



After that was installed (above left), the replacement front fender liner piece I found on RockAuto (above right) was installed on the left front as well. Now all of the liners are good.

COOLING SYSTEM UPGRADES & REPAIRS

One upgrade that goes with virtually every track-centric build is a larger and more efficient radiator. When the OEM unit has plastic we replace it with an all aluminum unit, too. We normally look at Mishimoto / CSF for some cars, but when it comes to Corvettes we have used one brand and had perfect success: DeWitts.



The factory single core aluminum/plastic unit in this 2006 model car was ~16 years old at this point, and plastic parts heated to 250F all the time don't last forever. The massive, all aluminum DeWitts drop-in unit was purchased to replace it. The core thickness difference is shown below - it is massive. We have successfully used these in C5s before so it wasn't a tough choice getting one for our C6, but it wasn't an inexpensive upgrade.



Removal of the old unit starts in the engine bay from the top, but we had some other damage that needed to be repaired and the entire front bumper cover was removed for that step.



The lower radiator support on all C5 and C6 models is a fabricated aluminum structure - and it is the lowest thing on the car. With an aggressively over-lowered front ride height, this car's lower support was smashed before we bought it. This is common and the aftermarket factory replacements are not expensive. The plastic bits that attach to this were holding many broken pieces together on one side.



The replacement was raw aluminum, and we didn't bother painting it. As we have seen before these low cost replacements tend to fit well and include all of the factory installed riv-nuts to attach all of the lower bits and pieces. Brad swapped that on when doing the Z51 brake upgrades and the cooling system work.



All new radiator hoses and a new 205?F thermostat were installed at the same time as the DeWitts radiator upgrade and lower support work went in.



Since it is a part of the pressurized cooling system, the factory remote reservoir and radiator cap were replaced as well. I had bought one for my truck at the same time, so that's the second one in the picture above left.



With essentially a brand new cooling system and a massive radiator upgrade, I felt confident that the coolant temps wouldn't be a worry for future track test - and they have not been. An ounce of prevention is indeed worth a pound of cure.

FRONT AIR DAM REPLACEMENT

The C6 has a cooling system that is a "bottom breather" - meaning, much of the airflow for the radiator comes from under the front lip of the car. The lower grill feeds the ducting for the radiator with a section at the top that feeds the air cleaner. As you can see the front brake ducts are also under the car.




GM utilized a lower air dam made of three plastic pieces that kept the air going to the radiator (and brake ducts) instead of underneath the car, reducing lift. With the ultra low front ride height somebody dialed into this car the air dam took a LOT of damage and needed to be replaced.



I found the GM replacement piece online for a good price and Brad installed those when he wrapped up the cooling system work. This is technically part of the cooling system so it was a good time to do this.

continued below

[Fair!]

continued from above

FRONT & REAR TOW HOOK DESIGNS

While the front nose was off I pulled engineers Zach & Myles into the C6 project to develop some new, bolt-on front and rear tow hooks for the steel framed C6. Sure, we make tow hooks for a number of cars, but why make these for such a "mature" Corvette model like the C6 (which has been out since 2005)? Well the offerings we have seen from others aren't... great.



In 2020 we made some unique and new tow hook designs for the C5 Corvette (shown above) that were very far from a "copycat / me too" design, and they have sold very well. We looked at the existing C6 offerings and came to the same conclusion - we need to make Vorshlag versions. This is another reason why we bought this car - product development, when it made sense.



Like our C5 front tow hook design, this steel framed C6 front tow hook mounts between the lower radiator support and the frame rail. Our C6 design also has a "tab" that is bent up and "pushes" on the back of the bumper beam when the car is towed forward from this point. The tow hook has a bend down, then then passes through an unused section of the lower grill - which we add a slot to some plastic (see above right) for the pass through.



I have personally pulled this C6 into and out of our trailer a dozen times with this front hook - I'd confidently have a tow truck driver pull it up onto a flat bed from here. It is VERY substantial.



Out back our crew removed the black plastic lower valance and we took a look at how we wanted to mount the rear tow hook. Like all of our designs we never want to make a customer cut through painted body panels to install the hook, but the black plastic bits are fair game.



Like the front, our C6 rear tow hook has a 2.0" diameter hole and is made from 3/16" plate steel, which we CNC cut in-house. The rear frame rail and bumper beam have a height difference so we weld on a spacer to the hook where it touches the bumper. This hook bolts to the steel frame and bumper structures with 4 bolts. The lower black plastic valance needs to be slotted to allow the tow hook to pass through. Nice and clean, and removable.



Our prototype pieces shown that went onto our C6 were spray painted red, due to time constraints, but our production tow hooks are powder coated in gloss red for a long lasting finish. These are the strongest bolt-on tow hooks on the market and they have been selling well for the past year. We keep making our various tow hooks in ever larger batches and will keep expanding our designs to other car models over time.



Lastly, I had our crew modify an existing towing tie-down strap anchor point design into a a C5/C6 specific one. This 3/16" CNC cut plate steel part can be bolted onto the rear lower control arm / sway bar point at the rear subframe, as shown above. We are updating this design and will have it for sale soon, but the Tow Hooks have been selling for almost a year.



I have a pair of these on the back of our C6 and it makes strapping the car down in the trailer SO much easier now - just reach under the car, attach the hook end of the straps into the long slotted eyelets, and then anchor the rear. Easier than going through wheels or running an axle strap through the subframe, as I had been doing before.

TRACK TEST #3, MSR-C 1.7, MAY 27, 2021

I brought our narrow body C6 out to MSR on a Thursday member day to test this latest round of changes on their 1.7 mile CCW course. Weather was 79F and cloudy, and the track surface had been scraped and patched recently to repair some bumps in recent repaving work. A little rain the night before left a small wet spot on track entering Turn 9, but nothing impacting lap times.



Again, Project New Balance had a number of changes from Track Test #2, namely all new calipers and rotors (Z51 brakes), tow hooks, and a "performance alignment" (-2.5 deg camber up front, -1.0 out back) that we had a nearby shop perform on their laser alignment rack. We really needed more rear camber, as this could make for a slight imbalance in cornering, but we will address that the next time it is aligned. The alignment shop we used had never done a Corvette - and it turns out they made more than a few mistakes (more on that below!)



All told I was a solid 1/2 sec slower than test #2, with the rear brake lockup was no better than before, even with all new brake parts. I used the exact same 275mm Hankook RS-4 tires on 19x10" wheels and G-LOC R12/R10 brake pads. You can see my horrible, best lap here on YouTube.



This was a depressing day of testing, and I left the track in a totally foul mood. The rear brakes kept locking in all 1.0g stops, and I tried every braking technique known to man - the only way to manage it was to UNDER brake into every corner. Straight line brake, stay under 1.0g, and never trail brake. It was also twitchy as Hell - I've been doing this stuff for 35+ years and I cannot remember a car that was actively trying to kill me on track like this one.

THE GREAT MYSTERY - C6 LEFT UNBALANCED!

This third track test was the beginning of a downward spiral into me hating this car. I watched the videos from that track day and could not put my finger on why it was slower than test #2? It was the same tires, same brake pads, and similar conditions. In this test, plus track tests #4 and #5, it took everything I had in my 3+ decades of track experience to keep that car on track - and still went 0.6 sec slower! I spent months and two more track tests fighting this car before we had a EUREKA moment.



Yes, the ABS programming was garbage, and we eventually fixed that with a full Mk60 ABS swap (below) - but even then, the lap times still didn't improve; I never could beat track test #2's 1:26.2 time! Why???? I searched my brain, watched my videos and analyzed data, and it finally occurred to me. In track tests #3, #4, and #5 the car was super twitchy, mid corner, and would never take a set. Sometimes when you are stumped you need to step back and CHECK THE BASICS.



We didn't make the lap times worse with the Z51 brakes - the alignment did. The shop who did the "performance alignment" on this car was not at all skilled at motorsports alignments. They have screwed up every alignment we have taken them, badly, and we quit using them long ago. Sure, we noted the lack of rear camber after looking at their work sheet, sure, but we neglected to CHECK THEIR WORK first hand.

It wasn't until March 2022 when Brad was installing the MCS coilovers that he found something. I always insist that any car getting major suspension changes go through a "baseline measurement" session before the work, then another after. We check ride height, camber, and toe at each wheel - before and after. And that is when Brad noticed that the alignment shop had REVERSED my written rear toe request... they had put 3/16" of TOE OUT in the back instead of 3/16" of toe in!

Which explains why the car was so twitchy in corners and would never "take a set" after the turn-in phase of the corner. This is why the car kept getting slower and was so hard to drive. Sure, the lack of ABS function made turn-in challenging, but this was a mid-corner phase oversteer/unbalanced setup. Dumb mistake that I should have known to check. I'm mad at myself more than anyone else. How did I miss this??



This alignment mistake was unfortunate and wasted a lot of time on this project - we would have installed the MCS dampers a half a year ago if the car would have just... progressed. The piss poor lap times kept making me wait, stalling out the project, and it sat in storage for months while we worked on other projects. We kept going down the ABS rabbit hole and finally fixed that, but it was still slow and twitchy on track afterwards. That's when I knew it had to be something else. The wacky alignment was the problem for so long, but it was impossible to even see that small amount of rear toe out visually - but boy did it impact the handling!

WHAT'S NEXT?

There is much more to share to cover the work we completed from late May of 2021, but that alignment revelation came only recently and it impacted the next many months of work and two more track tests. I am going back to the track later this week, with a proper alignment scheduled on a rack at a real motorsports shop that understands the importance of rear toe!



Until then I will save the coverage of all of the other modification work we did in late 2021 and into 2022 for next time. That will include the new seat brackets / seat install, harness bar, harnesses, Mk60 ABS (plus another aborted ABS install), big wheel testing, and more.

Thanks for reading!

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Project Update for June 16, 2022: The last forum build thread update here only got us thorough May of 2021, so this is be big "catch up" post that covers our C6 work from May 2021 to April 2022. So much work has been done to this narrow body C6 since then - a seat upgrade, harness bar, 6-point harnesses, an MCS coilover install, ABS testing, two ABS swaps (one of which worked), a carbon front lip, baseline dyno run, wheel testing, brake pad swaps, alignments, wheel hub changes - as well as five track tests to verify all of these changes!



As you will see, there are several things we attempted in this series of tasks that did not work - and I label these in the headers of each section as FAILS. There were both wins and few fails on the C6 over the course of the last year, and while I'm not proud of choosing to go down the wrong paths, I don't hide my mistakes. As always, we try to share what works and also what does NOT work, so that you don't have to learn the lessons we did if you attempt to replicate this work on a similar car.



But we did a number of modifications that were solid WINS, which helped contribute to FIVE SECONDS of lap time improvement from our initial baseline lap times, all from the work shown here (and we have gone 2 more seconds quicker since, which I will show next time). We try to only add ONE VARIABLE per track test outing so that we can isolate what works and how time much it is worth. Who else does this level of testing - we're at 10 track tests to date - and shares that with everyone? If you can point them out to me, I'll buy them a beer.

TRACK TEST #3 - MAY 27, 2021

As I mentioned at the end of the last post, the "performance alignment" we had done at a local shop really jacked this car up - and Track Test #3 was the first time I drove it like this, and at MSR Cresson on their 1.7 CCW course as always. We always strive to test on the same track configuration / same driver / same tires / same conditions.



I brought the C6 out a Thursday in May, with weather at 79F and cloudy, and the track surface had been scraped recently to remove some bumps from a recent repave (it has since been paved again). A little rain the night before left a small wet spot on track entering Turn 9, but nothing impacting lap times.



This was the first time we ran the car with the upgraded Z51 brakes with new calipers and rotors, the same G-LOC pads from before (R12/R10), the new tow hooks, and the "performance alignment" with -2.5 deg camber up front, -1.0 out back. The rear toe out was not obvious, and of course it WRECKED the handling - and lap times suffered.



I was a solid 1/2 sec slower than test #2, as both the rear brake lockup issue was still bad and the rear toe out issue made the handling just TRASH. Ran the same 275mm Hankook RS-4 tires on 19x10" wheels. I thought the ABS was all of the issue here, but it was only partly to blame (but still a major hiccup).



Extremely frustrating day at the track - going slower while fighting both handling and brake issues. After many laps going nowhere I loaded up and brought the C6 back to the shop - we had a lot of work to do.

CORBEAU SEAT INSTALL + CUSTOM BRACKETS

This seat upgrade was eluded to in the last two updates, and we tackled this over early May through late July 2021. If that seems like a long time - it is. And we didn't install the second seat (passenger side) until June of 2022. This upgrade isn't exactly a "win", but it wasn't quite a fail either. I'm not going to release this seat bracket for sale yet because 1) it will ONLY work on THIS model of seat, 2) I'm not sure we've found every inch of room there is, and 3) I don't know if this is a viable product to release. I will explain more below.



Part of the initial delay on the first seat was because we designed and built several iterations of a bracket assembly for this "bottom mount" seat and slider, trying to gain both headroom and rearward travel in the cramped C6 cockpit (the C4-C7 Corvettes are all very small inside) while keeping the overall seating position the same as stock. To be honest, the seating position we have now is less than perfect for anyone over 6' tall with this bracket + slider setup.



The Corbeau seat itself is a VERY nice upgrade over the base C6 or even the C6 Z06 seats we have on hand. They have a lot more leg support, shoulder and rib support, and shoulder harness pass-thrus in the seat back. And the shoulder harness slots are above the top of my shoulders, which was a good thing - not all seats fit taller torsos. There is also a path for the lap belts but not a pass-thru for a 5/6/7 point harness anti-sub straps. The covering comes in several styles and stitching colors (not my favorite but she likes it!) and we ordered the driver's seat with an optional seat heater - its good for my lower back and Amy loves these things (we didn't hook that up until June 2022).



Like most Corvettes this 2006 base model came with a power driver's side (45.6 lbs) and a manual sliding passenger's side seat (35.8 lbs). The Corbeau is slightly lighter 28.7 lbs, without the slider or our final seat bracket. And while the Corbeau is considerably more supportive, with the external bracket and slider we had to build we did not gain any additional headroom - which was one of my major goals.



We started with the flat style seat base bracket design we have done for the C5 and other cars, but with this bottom mount seat we quickly realized we could never get the base tilted back enough to fit correctly in this chassis. Side mount racing buckets can be adjusted for tilt in the side brackets - not an option here (we needed about 7.5 deg of base tilt to match the stock seating position). Even with the "OEM style" brackets we started mocking up it visually it looked like the Corbeau would be shorter in height, but that was misleading.



After literally three months of tweaks we locked down the "final" design and put the driver's seat into the car. These went in raw steel and we made another set for the passenger side, that was eventually powder coated.



To keep the stack up height to a minimum we made the brackets separate front and back assemblies, which we CNC plasma cut in minutes, bent to shape, and TIG welded. And since this was going to be a dual purpose car we wanted to include harness attachments for 6-point belts as well as the OEM 3-point seat belts. We also ordered these Airbag Simulators (seat sensors) from Vetteworks Motorsports, which should keep the airbags working and the lights on the dash off. Plug these in BEFORE you turn the key on during your seat install.



Again, with the seat installed with our brackets AND a slider it sat a little higher than the stock seat, and a bit too far forward, due to the OEM brackets and slider being much shorter and sort of built into the bottom of the seat (the height efficiency is good). Our "anchor shelf" for the clip in harness anchors on the back of the bracket is keeping the seat from sliding back about an inch. I've been looking at this for 8 months now and still want to chase down a few other tweaks.



We also didn't save much weight with our Corbeau seat + slider + bottom brackets (40.9 lbs), vs the stock power seat (45.6 lbs) or manual seat (35.5 lbs). But for a tilt back seat with all of the bracket mounts for the 6-points it isn't bad. This design was a pretty "big ask" - to improve on the height of the stock seat using a bottom mount tilting aftermarket seat AND keep a slider AND add the additional 4 harness mounts. What we have now is not ideal, but the seats themselves DO feel really good and support so much better than the stock seats it is worth the less than perfect position - for now.

HARNESS BAR INSTALL

This upgrade is an unusual one for us - adding a "harness bar". Normally I am one to preach the benefits 4-point roll bars, for racing harness shoulder strap mounting AND rollover protection. But here, in the already tight confines of the C6 cabin with full interior, there's really not sufficient room for that - in my humble opinion.



The main steel structure of the base C6 is hydro-formed steel tubing, and that goes into the roof's "main hoop", shown above on a "naked" C6 Z06 chassis (which is aluminum). I feel that the factory "main hoop" structure of the C5/C6/C7 is adequate in 99% of rollover situations (which I have yet to experience in tens of thousands of track miles over 34 years of doing this). For a Wheel to Wheel car, of course you need a cage. And for not tall drivers that don't mind cutting up their Corvette, sure, get a roll bar. For the goals we have on THIS car, a harness bar is adequate.



I try to set the best example with my personal safety gear in whatever I am driving on track, and you will see me even on the hottest days wearing 3-layer SFI fire suit, the best helmets, HANs and more. But I'm not some "safety nazi" that says anyone "who tracks their car without a cage will die!" like some. There's always a balance, and only you can know your needs with respect to personal safety, the tracks you run at, etc.



Like many Corvette track rats we chose the Brey-Krause harness bar for the C6. This is a hoss unit and they are a very trusted name in the industry. The images above show the relatively simple steps needed to mount their anchors to the rollover hoop, then the hole trimming needed for the interior panels (if you reinstall those).


With the interior panels in place this harness bar looks right at home, and still allows access to the full rear cabin storage area. We left the carpet out once the MCS coilovers went in, but I will talk about that in a later section.

SAFECRAFT 6-POINT HARNESS INSTALL

With the harness bar installed and our lower seat brackets adding the 4 lower anchor points for clip-in harnesses (laps and anti-subs), it was time to choose the racing harness brand and style.



For many years we have been selling and using Schroth harnesses exclusively, but through a racing relationship that Tim here had with another Pro racer, we have started using Safecraft harnesses and nets. These are really and truly designed by a racer for other racers, and the feel of the buckles, the releases, the tensioners and straps is all "next level". I ordered these in red (of course!) and these use a hybrid 2" upper and 3" lower shoulder harness strap with 2" lap belts.



Installing the lap belts and anti-sub belts isn't easy on any of these composite cars, simply because there isn't much floor structure to bolt to or room behind the seat to place the anchors. We incorporated the anti-submarine and lap belt anchors into the lower / rear seat bracket portion, which again - cost us some rear seat slider travel. But the anchors are solid and work fine. The anti-sub portion slips between the lower and back portions of the tilt back seat and you sit on the harness and bring it up around your crotch. With a proper hole in the base of the seat you don't have to do that, but this is a compromised street/track seat - as are all tilt back seats.



How you wrap the belts around the harness bar matters - see the image above left, which should match the NASA/SCCA General Competition rulebooks. Again, without holes in the seat back it is nearly impossible to use harnesses, and GM didn't start making "track worthy" seat options until the C7 model. This upgrade is better than nothing, but not as good as a fixed back racing seat. And yet we can still use the 3-point retractable OEM belts.



Driving on the street with the 3-point stock belts is fine, and driving on track with proper 6-point harnesses is better than fine - but not yet perfect. We'll keep looking for that last inch of rearward travel and height, but it might not be there with a bottom mount tilting aftermarket seat. Stay tuned for more.

JONGBLOED WHEEL ORDERING & TEST FIT

Early on in this build I started making plans on fitting the widest tire and wheel package possible for a narrow body C6. Nobody ever runs these cars and I wanted to see how far we could push it with the stock fenders.



On a widebody C6 we've spec'd and built many sets of 1-piece 18x12 / 18x13 wheels and 335 / 345 tires, which is a tight fit but they work (some rubbing up front inboard) and makes MASSIVE grip. I knew we'd not get to those widths but I wanted to see how far we could push it. As I have preached for 30+ years, tires are almost EVERYTHING when it comes to autocross and track performance, and you can NEVER have "too much tire". We've proven this time and again on so many cars and all power levels. The C5 below left is one I have tracked and autocrossed many times and on the 18x12/13" Forgestar wheels and the 335/345 Hoosiers is is unbeaten in autocross across dozens of events.



On the same wheels and the 315mm Yokohama A052 street tires above it recently set Fastest Time of Day, over some tight competition - with only 425 whp in a tight parking lot! The FRS above right is our 2013 that we documented here with the same "make a change / track test" scientific method. The change from 215mm to 315mm tires was the single biggest change we ever made to that car on track, dropping 2.5 sec at the same MSR Cresson 1.7 CCW course.



Our two sets of 19x10" wheels were done to give us a "control set" to use across many track tests (9 so far) and the 275/35R19 Hankook R-S4 tire is very consistent over many laps also (the image above left is with a 295/35R19 Hoosier R7, which we mounted later - but haven't gotten a good lap on yet). We knew that 275 Hankook tire would hold back the car's on-track performance, and we wanted to be ready for whatever tire we could jump to beyond that little 275 for time trial or whatever competition.



In march of 2021 - before we had even received the first set of 19x10" wheels from TireRack - Jason measured the stock wheels and determined the maximum wheel we could fit, theoretically. Again, the aftermarket was not pushing the narrow body as far as we had hoped, so we "went for it" and came up with 18x11" front and 18x12" wheel specs that were "max fitments".



Normally this is where you'd see me talking about some custom spec'd Forgestar wheel... but their wheel blanks could not accommodate the massive inboard offsets needed to fit these sizes to a narrow body C6. So it was time for a 3-piece wheel, and we had been in talks with Jongbloed for many years - now was the time to get a set to test out.

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We ordered the wheels in 18x11" for the front and 18x12" for the rear, with red centers. If we got the numbers wrong we could re-order the rim halves and get them adjusted narrower or with differing offsets, but that's still a costly change to make. So in late July 2021 we mocked them up on the car without tires...



This is the best way to check a new set of wheels - before tires are mounted. Some wheel makers even put big decals on the wheels that say this "if you mount tires to these wheels you own them!" So we mocked these up on one side of the C6, with one front and one rear.



They fit pretty well straight away, but I was worried about some inboard clearance with tires mounted. Sadly the 315/30R18 Yokohama A052 "200 TW" tires I wanted were on backorder (and stayed that way for months) so we would have to wait to mount those up. Plus I wanted to complete all of our initial track test and ABS testing on the harder R-S4 tires. I figured this would be handled in a couple of months but that stretched out into early 2022... as did the backorder on the A052s!

BASELINE DYNO RUN - BONE STOCK LS2!

I dropped off the C6 for a baseline Dynojet rear wheel dyno pull on June 15, 2021 at True Street Motorsports. They don't really do much LS tuning anymore but they got me in for a few pulls, which I like to do on all race cars initially before any mods or annually - as sort of a checkup, or annual physical. Anything weird seen in the dyno, or unexplained changes year to year, are always worth exploring.



As I said in my first post in this thread our 2005 C6 Corvette 6 speed made 355 whp (I've long lost those charts) back in 2004, so I had hoped this 45K mile 2006 would make a similar number. And it did - it made 360 whp / 367.5 wtq with the harder SAE correction factor.


With the more generous "STD" correction factor it made 366.5 whp and 374 wtq - but nobody uses STD except drag racers. NASA and most road race groups use SAE, which is almost always lower. This baseline will be compared to later, after we installed long tube headers + Z06 exhaust + cold air intake and filter.

CARBON FIBER "ZR1" STYLE FRONT LIP (FAIL)

In July 2021, around the same time as the seat install was wrapping up, we received then installed this carbon fiber front lip from Extreme Dimensions / Carbon Creations. I ordered these + some ZR1 style side skirts and tire walls, and it was ... well, a mixed bag. I noted it as a FAIL in the header above for one reason (brake cooling blockage) but it had some good features, too. Let me explain.



Visually the part looked great, and it was marketed to fit the "narrow body C6" front nose. And it did indeed fit the narrow body nose - but sadly the inlet scoops were NOT lined up with the brake inlet ducts under the nose (see bottom right). So the scoop section has to make a detour outboard to shovel air to the brake cooling inlet (see above right).

And the bottom line is - THIS DOES NOT WORK well because this splitter lip effectively BLOCKS the brake cooling almost completely. I didn't want to believe this as I spent a decent chunk getting these parts, and we spent a lot of time installing the splitter, but track testing of rotor temps with the splitter on-off-on (A-B-A) proved this. Just took us several months to get to the point where the brakes even WORKED to be able to test that.



Above you can see the lower OEM deflector plastic sections on the ends we had to remove to be able to fit the splitter in place. It has zero instructions so you have to just fumble your way into finding this. Sadly these flaps help create a high pressure area in front of the brake cooling inlets (above right), and removing these outer lower air deflectors makes the brake cooling a lot less effective - but so does nearly blocking them altogether. On the plus side, removing these side flaps does make it MUCH easier to strap the car into the trailer without scraping the hell out of your arms. That might not seem like a big deal to you, but when you load or unload a car 30+ times, this adds up!



The C6 Corvette is a hybrid of two styles of front end radiator cooling flow - it is both "mouth breather" and "bottom breather", so this splitter has to accommodate both flow paths. And it does so rather well - we did not see any change in cooling efficiency with this splitter, and I was worried about that.

Normally on a purpose built track-only car you block the lower inlet, re-route all radiator flow to a front "mouth breather", and redesign all of the radiator ducting to make this work better. Which is a lot of work - this GSPEED cooling kit for the C5 starts at nearly $5800 and includes a plywood splitter.



The sad fact is, because it blocks the brake cooling, this carbon splitter should not be used by track folks - unless you are willing to completely redesign the brake cooling inlets. Zach here spent hours drilling holes and adding rivets to mount this piece, and it sure looks sexy, but the compromises to brake inlet ducts are real. I have some data from a later track test that will show how this raised front rotor temps by +250 deg F - for now, pulling this off was the right change. We might go back and re-add this at some later point but not until we really need a touch of front downforce or show car cred.

PANAVISE BASE + RAM PHONE / CAMERA / AIM HOLDER

The 2005 era C6 Corvette's interior has aged a bit, and one of the things it is missing for today's consumer electronics is a Apple /Android Carplay style radio. In place of that (and one of these is in the plans), it still needs a decent spot to mount a smart phone - and if you have followed my build threads you will recognize the giant RAM quick release 3-axis phone holder that I have in literally every vehicle I drive.



For the first 4 track tests I was using a suction cup mounts for the AiM SOLO DL lap timer / data logger, another for the Sony vidcam, and a third for the RoadKeeper dual 1080P camera system. All of these suction cup mounted devices were blocking my view forward a bit, so it was time to address this.



Jason here at Vorshlag turned me onto PanaVise, a company who's been around for ages (with the same 1998 era website) that make these little steel brackets that bolt into specific car and truck models without cutting or drilling. They tend to snake them between trim panels and radios, and bolt to a rigid dash mount for the radio. Brad installed the C6 Corvette version of the PanaVise bracket + a 4-bolt RAM 1" ball base, which the PanaVise is made for.



Ever since this late July 2021 install I have used this 1" RAM ball mount with a 6" arm to hold either the RAM phone holder (above left) or the AiM SOLO bracket (above right), which de-clutters the windshield view by one device. I have also settled on one main video camera (the dual vidcam RoadKeeper) for most of these events, because I scratched the lens on the Sony. I've since lost about 50% of the video taken with the RK camera, and will be moving back to the Sony soon. Long story there.

"LOWER BITE" REAR PADS (FAIL) & OTHER STOCK ABS TRICKS / TESTING

So by this point in July 2021 I'm really starting to hate this car, simply because we cannot even get a decent "baseline" lap with the stock suspension, upgraded 275mm R-S4 tires, and Z51 brakes. Why? Well ever since we added the R-S4 tires the rear brakes keep locking up - it happens on the street and into the entry of any corner that involves braking. If you exceed 1.0g braking force on any stop, the rears lock (for a long second), which makes the car violently tail happy, and if you don't let off the brakes the rear will come around. All I am doing on track is managing the rear lockup, not focusing on "driving".

One of the many "fixes" we heard from many "GM ABS Excusers" was that you cannot run a rear brake pad with any "bite" or higher friction coefficient in the rear. So after 2 track tests with the rather mild R10 compound G-LOC rear pads (coupled with R12 fronts) we swapped in these "Brake Best" parts store branded ceramic ultra quiet pads in the rear.



Of course this didn't fix a damned thing and the rear lockup continued. We left those on the car in for the next few track days as well as a half dozen ABS street tests - where we altered rear tire height, front tire grip levels, rear grip levels, etc. We spent hours and hours changing variables and doing street tests - but the rear brakes kept locking at anything higher than 1.0g stops (the rears would "only" lock for about one second, then unlock, then re-lock, and slowly pulse until you came to a stop). The only "fix" was to swap in the original 500 TW craptastic rear tires, which cannot generate enough rear grip to get into this "bad programming" area.

TRACK TEST #4 - AUGUST 20, 2021

I did track test #4 with these low bite rear pads and the harder compound, stock 500TW rear tires, and it DID make the rear brakes stop locking - but the rear grip and balance were so far off that it slowed down from our baseline lap on a totally stock C6!



The track performance was complete and total garbage - and nobody likes a car that slows down from stock, not after we had a 2.5 sec drop in test #2.



At this August track test I used some one-time-use temp strips on the power steering line and alternator showing the fluid getting VERY hot, and with more seepage at the rag / cap. The alternator also gets pretty warm, but so far that isn't causing any issues.



After test #4 (August 2021) we didn't get back on track with functional Mk60 ABS until March of 2022 - and I forgot to swap the G-LOC rear pads back in. Well the soft pads didn't last 3 sessions, and actually ruined one of my track tests (Test #6). Lesson learned there - don't listen to "the internets" and use the correct track pads at all times, unless you want to go very slow. There is no good "fix" for poor performing ABS. And yes, the ABS programming on this base model car was likely worse than most Z51 / Z06 / GS C6 cars, which I have driven on track without this issue (but I can still Ice Mode all of those in a parking lot.)

These brake locking issues occupied too much shop and testing time, and ruined months of work spent chasing ABS fixes. It was time to do something serious to correct this, and we started with an ABS swap right after test #4.

Z06 POWER STEERING COOLER

After almost all track tests I noticed noisy power steering pump and some fluid around the cap, which we had swapped out with Motul ATF ester based fluids early on. There literally isn't better fluid to try, so it was time to look at a better power steering cooler.



We found an OEM replacement cooler complete with lines from a GM supplier and it was about $200, if my memory serves me. Much easier than building an elaborate cooler, changing all of the lines, etc. So during one of our many ABS tests in October 2021 Brad swapped in the C6 Z06's finned power steering cooler in place of the base models' hard line "loop".



It all fit and plumbing was a breeze - you never get this lucky in most cars, but this is one of several Z06 upgrades we would do to this car over time. Brad said he had to tap the two mounting holes on the cradle to fit the brackets, but the holes were there. Ever since doing this upgrade the power steering noise, measured heat, and fluid seepage was way better.

S550 MUSTANG ABS SWAP (FAIL)

In October of 2021 we brought the C6 into the shop and started an ABS swap using a junkyard sourced 2015 Mustang GT brick, shown below. I wanted to try this swap on a car due to the exceptionally good braking I've seen in S550 Mustangs AND the low parts cost. The Ford ABS bricks tend to be sold for $90-150 complete, with all of the hydraulics, pigtails, and the computer. There are no external sensors needed.

I will fully admit now that this ABS swap was a bad idea - but at the time, I had some incorrect information that said the 2015+ Mustang system was a valid candidate for an ABS swap. Well it might indeed be - but not without a lot of CAN trickery.



To be honest we have been able to swap the earlier 2011-14 "S197" Mustang ABS brick into a C5, and it has the best braking of any Corvette I have ever driven. It took a LOT of work and a special Ford Racing computer to make it function without external CAN inputs. I had hoped the newer S550 ABS would work the same way, but without the special Ford computer, it was a dead end.



But I still had Brad waste dozens of hours making a custom brackets to mount the S550 ABS brick into the C6, then plumb it into the rest of the system.



Long story short, once it was wired up and proven not to work, and I had since learned better information from a racer more familiar with S550 Mustang's without CAN wiring who told me this was a dead end - there's not a path to an ABS swap with this brick at this time. I'm convinced with enough effort we could make it work, but we had just completed another BMW Mk60 ABS swap in another car, so at a certain point it was time to "punt" and go down a path that had more support for ABS swapping.



All of that time spent wasn't a complete loss (just mostly a loss) - as we did learn how to make the car start with the GM ABS disconnected. We documented it above with some good graphics and pictures, which we will include into a separate ABS swap thread on our forum, to act as a knowledge base for future use. Why my own forum? Because it has been up for over 20 years, as has my Smugmug gallery (50K images+). I trust it better than some random forum or free photo hosting site.

BMW MK60 ABS SWAP

I let the C6 sit from late October '21 to early February '22, because I was just disgusted with how badly the brakes were working, then the S550 ABS swap being a dead end. But after we had some room in the shop we brought the C6 back in for another go. I had been purchasing the parts needed to do the BMW E46 M3 Mk60 ABS swap on this car.



The components you need include the correct year / model of Mk60 ABS brick, two external pressure sensors, and a yaw sensor (the later S197/S550 ABS systems have all of these within the ABS brick). There's about $800-1000 in parts from the right sources.



You also need a stand-alone wiring harness made for this swap, which right now costs about $1200 from sources like Racing Harness Technologies (who we have used several times). RHT can also supply the pressure sensor adapters like the ones above, which is $150 but could be higher (they come from Germany and take many weeks to arrive).



We had to make a pedal switch to let the system know you are engaging the brakes. And of course this C6 wo9uld need different wheel speed sensors (active). More about that in the section below. Brad built the bracket above to mount the Painless Performance brake pedal switch.



The brake pedal actuation switch doubles up with the OEM clutch switch (top left) and the yaw sensor has to be mounted in a very specific orientation - which required another custom bracket.



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Brad was able to sneak this BMW M3 yaw sensor behind the ash tray, with some careful trimming. This is centrally located in the chassis, where it needs to be. The Mk60 system can be mounted pretty much anywhere, but it gets crowded under the hood. We spent some time looking all over the chassis for a spot to mount this, and noticed that some C5 / C6 Mk60 swaps were put back behind the LF wheel, where the windshield washer bottle normally goes.



So that's where Brad mounted the ABS brick, on another custom bracket he built with high temp isolator mounting bushings. On a pure track car / race car these are often moved inside the chassis, as a heavy crash could damage the ABS unit or lines. But on a street car this is a common spot.



The ABS brick is marked in German but it is easy to find the translation. Brad made new brake hard lines from the master cylinder (below left) to the brick, and from the brick to the 4 original brake hard lines under the hood.



After all 6 brake lines are connect it is time to splice in the 4 pairs of wheel speed sensor wires. Then add the two 30 amp fuses to power the harness, mount the OBD port, and then install the ABS trouble light (if it is "on" something isn't right).



That is a quick overview of the Mk60 swap on a C6 - we will put all of this and more into an separate ABS swap forum thread later.



We did our initial testing with the crappy stock wheels and 500TW tires, but quickly moved up to the Hankooks. We left the front fender off during the shake down testing on the street, and we did have one tiny leak that needed a new tube nut to fix. Now all you need to make this Mk60 work is the correct style of wheel speed sensors, which I will cover below, as well as a tiny bit of programming.

C5/C6 WHEEL HUBS + ABS CHANGES

The C5 Corvette had an integral wheel hub with a speed sensor built within, and that generation had a certain type of speed sensor type called "passive" (grey or black sensor wire), which carries over into some C6 models (like our base model 2006). The 2009+ Corvette Z51/Z06 model cars changed to an "active" type of sensor (yellow wire), but the wheel hub itself was physically identical. Well, there were OEM front and rear models - with the rear units having splined opening of either 30 or 33 splines.



In the above left pic you can see some OEM "front" hubs (grey wire) from our C6 without the splined center hole, and the "rear" style with the splined opening (yellow wire) - which can be safely used on the front without a halfshaft/stub axle holding them in place. And of course we always like to put ARP long wheel studs into these for various reasons - when ARP has them in stock.



In the same month we were doing the MK60 ABS swap / hub upgrades on the C6 we were also doing the same work on a Gen I CTSV, and it needed to move to these "active" hubs for the Mk60 to be able to read the wheel speed signal correctly. This CTSV needed 30 spline rears, as did our base C6... which was tricky to get the Active hubs for - and you cannot get SKF X-tracker hubs in Active sensors in 30 spline, it simply does not exist. So on the back of that CTSV and the back of our base C6, we had to use "off branded" active 30 spline hubs.



And that is the lesson we have learned - you ALWAYS want to use SKF X-tracker hubs on a C5 or C6. And yes, they cost 2-5x as much as the cheap China replacement hubs, but that's because they last 10x longer or more. The price shown above right changes WILDLY every month and the $210 cost for 33 spline X-tracker hubs has been as high as $300 recently. Just prepare to spend that amount or have constant failures.



I was "being cheap" and ignored the "only use SKF" advice on our C6, but we had 4 out of box failures with other brands. The bearings were either notchy/loose right out of the box or the speed sensor circuit was dead. We started checking resistance on each hub before we did the work of swapping the ARP studs and installing the hubs, to save time sorting through junk.



I bought one SKF 33 spline hub for the front and one "C-TEK" brand, and the C-tek lasted ONE DAY on track, then it had movement in the bearing. So now we have two SKF 33 spline X-tracker fronts on the C6, and two off branded rears. To swap to 33 spline SKFs out back we need to swap the rear axle shafts, and that is on the short list for the future.



Once you have all 4 wheel hubs changed to the yellow wire "active" sensors you need to connect to the OBD port that came with the Mk60 wiring harness, tell the ABS brick "you are a 2003-06 BMW E46 M3", then clear any fault codes. You can also rotate each wheel and see wheel speeds generated in real time, with the right scanner. Then it is time to go do some brake tests! That was a good day, once we had the C6 stopping reliably at 1.15g with zero lockups. Huge win!

TRACK TEST #5 - MARCH 24, 2022

Amy and I drove the narrow C6 for the first time on the Mk60 ABS and 1 year old 275mm RS4 tires. I also drove a customers 2022 BRZ with MCS TT1s and 245 RT-660 tires.



In the brief video below I explain the "feel" of the car, the performance of the brakes, and do a quick walk around. It was a very cold morning (34F) and it took a lot of laps to get the R-S4 tires up to temp.



That cold ultimately hurt my lap times until a later session when it warmed slightly (the AiM worked but the video camera took a crap). I managed a best of 1:26.4 in the C6 with the ABS working, but still the stock suspension - not what I had hoped, and while some 1:25.X predictive times flashed by I could never string the lap together. All of the video from the C6 was hosed, but I got the '22 BRZ down to a 1:26.9 on my single solo lap on some very hot tires.



Driving two very different cars back-to-back showed me several things about the C6 - and as you can see the BRAKE DIVE is a bit extreme now, since the brakes actually work. The car is wallowing around like a pig, and it needs REAL spring rates and REAL dampers (so we installed the MCS coilovers next).



The braking performance on the BRZ (see video above) with stock calipers and track pads was also better than what the C6 can do at this point - we needed a more aggressive pad on the C6. The BRZ on MCS coilovers was so much flatter in corners, under braking, and easier to drive too. The gen 2 BRZ at 2750 pounds, MCS coilovers, Falken RT660 tires, and making 200 whp, and it is damn near even on track with the 360 whp C6 Corvette! (on worse tires and stock suspension) The C6 is also still slightly slower than the Spec Miata lap record (1:25.9) at this point - we need to fix this, straight away!

MCS RR2 COILOVER INSTALL

Just a few days after track test #5 (March 29th) Brad started on the MCS coilover install on our little C6. These shocks have been sitting here patiently for nearly a YEAR while we sorted all of the ABS problems, but at long last it was time for the BIG upgrade that I felt would unlock a lot of lap time in this car, all by itself.



This mod is one we have done on countless cars and it typically unlocks 2-3 seconds per lap at MSR on the 1.7 CCW course. We utilized 700 #/in front springs and 650 #/in rate on the rear, with Vorshlag spherical top mounts at both ends. This is our softest coilover spring rate we offer, but with the spring rate of the OEM springs in the 150-200 #/in range, this is still massive change. Removing the transverse leafs removes a lot of "swaybar effect" (more on that later).



I was hoping for a small weight drop getting rid of the huge composite springs, but with the remote reservoirs the weight change was nearly a wash, with a 0.1 lbs change up front and 1.0 pound weight drop out back - nothing worth bragging about. We chose the remote reservoir double adjustables as I personally feel these give the most advantages of coilovers for the cost - the remotes increase shock travel, radiate heat away from the fluid, include separate Rebound and compression knobs, but without the cost of 3- or 4-way MCS dampers.



After checking / marking our "initial" specs (camber, toe, & ride heights at each wheel) the C6 went up on the lift and the stock transverse springs and shocks came off both ends. The front spring was a CHALLENGE to get off - Brad had to disconnect the lower arms to let them hang to be able to fish the spring out. The rear spring came off by compressing the control arm on each side, disconnecting, then letting the suspension droop.



We make spherical top mounts for both ends, but we have a unique way to gain "bump travel" and spring room on the front. We have MCS make the front shock inverted, with the body at the top and the spring on the bottom portion - we need that room to clear the upper control arm. Well we need a little more room, so we have a tool we include (top left) to mark the offset center hole to be drilled. The CNC cut plate is used to mark two new upper mounting holes, then those are drilled and the plate is bolted in place. Then the new center pilot hole is drilled offset to the inboard...



Then a hole saw is used with this 1/8" pilot hole to make a slightly larger diameter hole offset from the stock shock mount hole. This allows the bulk of our upper spherical mount to sit above the top of the "shock tower", gaining suspension travel and removing a rubber shock mount bushing from the damper load path. The offset nature of the hole kicks the top of the front shock inboard to help clear the upper control arm, too. It works really well on all C5 and steel framed C6 chassis cars, but not the aluminum framed C6 Z06/GS/ZR1 cars.



Out back we have MCS make the rear shock "non-inverted", with the shaft (and rebound knob at the top. We make our upper spherical shock mount to bolt into a "blind pocket" on the rear of a C5/C6, then ask our customer to drill a pilot hole then a hole sawed opening to be able to get to the rebound knob. We CAN order the rear shock inverted, with the Rebound knob at the bottom and no need to cut the access hole - but getting to that knob is so much hard, as you have to jack up the car to get to it.



In the rear I wanted to mount the remote reservoirs (with the compression adjuster) inside the trunk area to - also for ease of access to that knob. To do that Brad drilled a hole through the floor (which we mapped out carefully would not intersect with anything) to pass the reservoir and hose through. The "quick release" connector on the hose is deceptive - to disconnect that you have to discharge the 180-300 psi Nitrogen charge, then disconnect, then pass the hose through a smaller hole, then reconnect and re-charge. With this 1-piece aluminum spiral cover and small grommet we can just unbolt the cover and pull the whole reservoir through, when needed.



The finished install of the rear knob access hole and reservoir pass through hole + cover is shown above left. We left the rear carpet out for now, and just tied the reservoir to an interior composite protrusion for now. I can (and have) adjust the rear Rebound and Compression very quickly, just by popping the rear glass hatch. Up front (above right) the reservoirs were temp mounted to the stock airbox, as the hoses are long enough to snake under the frame rail and reach that "cooler" spot under the hood.



Brad finished up the install, ride height setup, and corner balance on April 1st. If you notice the front ride height is TALLER than it was before, as some previous owner had SLAMMED the front ride height on the stock spring adjusters. I drove the car to lunch a couple of times and really liked how it felt, how it cornered and slalomed, and the ground clearance was improved. We got busy but on April 13th I got the car back in the shop and Brad did a string alignment, to get the alignment in the ball park. Then we loaded the car into the trailer to do some more track testing the next day...

TRACK TEST #6 - APRIL 14, 2022

I drove the C6 on the 275mm RS4 Hankooks to test the MCS RR2 coilovers and newly installed Mk60 ABS. The string alignment Brad did found then fixed the wacky rear toe out issue (finally) that plagued this car since track tests 3 through 5. That rear toe out of a half inch in the rear had been making the rear super unsettled and loose. Coupled with the shoddy ABS programming it made this car a bear to drive, but all of that was better now with the alignment better and the new MCS coilovers in place. This was the day on track I began to hate this car a LOT less!



My plan was to start the morning off with a session on our "control tires", the 275mm Hankook R-S4s, then install some brand new 295mm Hoosier R7s on the other 19x10" wheels to throw down an even quicker time. And I chased a good lap time for 2 full sessions on the Hankooks, making driving mistakes and fighting rear brake issues.



I wanted to see the best the Hankooks could get to on the MCS RR2 coilovers and Mk60 ABS. I made a whopping 37 laps on these tires and put a tank of fuel through this car trying to catch the car's best lap time - saw 1:22.X predictive lap times more than once, but all I could complete was a best lap of 1:24.0 on the RS4 tires. I had a couple of weird braking issues that kept cropping up - now what had changed? I even had a couple of pretty big "offs" when the brakes seemed to weirdly just lose stopping power after 4-5 laps of driving.



I came in to both "take a look" at the brakes as well as swap over to Hoosiers, and that is when I noticed the issue - the "parts store" brake pads had been left on the rear and I burned those down to the backing plate, which was why I was fighting brake issues all day.



The weather was pretty cool and so was the track temp. This in-car video of my best 1:24.0 lap is in this video, linked above. At this point in the car I know something is going on with the brakes, but I hadn't pulled a wheel off to see the completely shot rear pads. I took a cool down lap after the 1:24 lap and then put in a hot lap, when I saw the 1:22.6 predicted lap pop up. I braked into the last turn (Big Bend) where I always do, but the rear pads were metal-to-metal by then and I went right off the corner. That's when I went in to change tires and noticed the pads, then I just loaded up and went back to the shop.

continued below

[Fair!]

continued from above

REAR BRAKE PAD + SMALL HYDRAULIC LEAK FIXES

The next week we brought the C6 in to swap out the burned up junk pads and put the R10 G-LOC pads back in, which seem to be wearing much better.



A small brake fluid leak was noticed at the Mk60 ABS unit, specifically at the ATEC sourced pressure adapters. Why this would have an O-ring is a mystery (it wasn't supposed to), so we removed both of those and replaced them with copper crush washers - and it has been 100% leak free ever since.



Considering how many lines / fittings / flares were changed this swap, it was remarkable how well this hydraulics work was. Thanks Brad!

TRACK TEST #7 - APRIL 28, 2022



At this point I am going to the track in this C6 pretty regularly now, and only two weeks after test #6 I went back to re-try my hand at that "best R-S4" lap time on the MCS coilovers. Once again I brought the Hoosier R7 set to swap on after I nailed that elusive 1:22 lap.



This time the car had rear brake pads on it, but the day did not go off without a serious hitch. I was on my third stint in the second 30 minute session and turning into Little Bend (a quick right hander) I heard a "pop" from the left front corner, then the car lurched to the left by one car length - putting my line in the dirt. Nothing hurt but my ego, and I came in knowing that a control arm bushing likely popped out. And that's exactly what happened.


I wasn't surprised as we have seen this happen on C5 and C6 cars regularly over the years, and we had planned to swap bushings after this track test anyway. This bushing issue cut my testing short with a best of 1:23.828 lap, only 2 tenths faster than the best at Track Test #6. I was just getting warmth into the tires and track surface but that 1:22 lap eluded me again! And once again I had video that was junk - no audio this time. I'm really getting sick of the RaceKeeper camera now.



Jerry was driving his car on the Michelin street tires and asked me to take a few laps with him riding shotgun, to see if I could find some time. Who says "no" to some laps in a C7 Z06 with the supercharged LT4 V8? This was just three fun laps, talking and joking with Jerry, where I pushed the tires and brakes maybe 80-90% and short shifted the engine by 500 rpm.



The on board "PDM" video logger showed a best of a 1:19.88 vs my AiM SOLO showing a 1:19.933. All in-car video taken in the C6 had no audio, so it is worthless. The above right video shows a quick sneak peak at what went wrong, as I was in the paddock looking for answers. Nothing I could fix that day, so it was time to head out.

LAP TIME PROGRESS - MSR 1.7 CCW

Over the last year we have taken this bone stock base model narrow body LS2 C6 - the worst variation they made in this generation - from a 1:28.7 lap down to a 1:23.8. That's a FIVE SECOND DROP with a pretty tame tire (275mm Hankook), coilovers, and an ABS fix. There is a lot left on the table (we've already gone 2 sec quicker - I will show that next time) but we're making real headway and got this coupe faster than the Spec Miata lap record... whew!

This list of best shows the progress on our little C6 from Test #1 to Test #7, with nearly each one on the same set of 200TW Hankooks. The 3 other Corvettes I've driven are shown in the ranking, as well as the 2022 BRZ I drove on Test #5, and all laps for this C6 are in bold:

• 2006 Corvette, Baseline Stock Lap Time, 245/275 500TW, stock pads tires (Test #1), 4/9/21: 1:28.743
• 2006 Corvette, G-LOC R12/R10 pads, 275 Hankook RS-4 tires (Test #2), 4/18/21: 1:26.248
• 2006 Corvette, G-LOC R12/R10 pads, 275 RS-4 + "Bad" Alignment (Test #3), 5/27/21: 1:26.823 (slower!)
• 2006 Corvette, G-LOC R12/Brake Best rear, 275 RS-4 / 275 500TW (Test #4), 8/20/21, 1:30.015 (even slower!)
• 2022 Subaru BRZ, MCS TT1 coilovers, 245mm RT660 tires, otherwise stock, 4/24/22: 1:26.927
• 2006 Corvette, G-LOC R12/R10, 275 RS-4, Mk60 ABS, stock suspension (Test #5), 4/24/22: 1:26.4
• 2006 Corvette, G-LOC R12/R10 pads, 275 Hankook RS-4 tires, MCS RR2 coilovers (Test #6), 4/14/22: 1:24.072
• 2006 Corvette, G-LOC R12/R10 pads, 275 Hankook RS-4 tires, MCS RR2 coilovers (Test #7), 4/28/22: 1:23.828
• 2012 Corvette C6 Z06, Carbotech XP10/XP8 pads, 285/335 MPSS, perf alignment, 9/16/16: 1:22.63
• 2017 Corvette Grand Sport, Z07 aero package, 285/335 MPSS, perf alignment, 9/16/16: 1:21.89
• 2017 Corvette Z06, Supercharged LT4, CCM brakes, cooling upgrades, 285/335mm MSC2 tires, 4/28/22: 1:19.933

WHAT'S NEXT?

I better stop there - this is already a MASSIVE update that took me nearly 3 days to write, compile and edit. We've already done two more track tests, upgraded to poly bushings, fitted the Jongbloed wheels and large 315mm Yokohamas, and dropped another 2 seconds. We have also had the car laser aligned at a motorsports shop, removed the carbon splitter lip, and tweaked the brake cooling. In the last two weeks we have added long tube headers / catted X-pipe, dual 3" Z06 mufflers, and a cold air intake, changed the thermostat - then had all of that tuned. More power and better noises are always fun!



We're also looking ahead to additional mods that are next, like a better fixed caliper brake upgrade - with lots of parts here to test fit and modify. We are keeping the "dual purpose" street/track theme as the main goal, so street legal and safe to drive around town. And we found a potentially decent class to compete with this car in SCCA Time Trial - their Tuning 2 class. I am going run this at ECR with the Texas Region SCCA TT this coming weekend in that class, so we'll know soon if we have made a winner or a loser!

Until next time,

Terry Fair @ Vorshlag

[Fair!]

Project Update for July 26, 2022: This update is only 6 weeks since the last one, but is still jam packed with work on our narrow body C6. The past few months have been a very productive with upgrades and work on this project - and it is where a bulk of track lap time improvement has been unlocked. The C6 is now a LEGIT fast track car, even competitive in a certain Time Trial class. I'm as shocked as anyone, with as hopeless as the first 10 months of this car went!



In this update we will cover work to this C6 on the following systems: upgraded control arm bushings, ball joints, a "real" alignment done by a Motorsports shop, 2 more track tests, an exhaust + header + cold air upgrade, custom dyno tuning, a second seat install, 6-point harnesses, a fire bottle, transponder install, and an SCCA Time Trial event. We also finally got the Jongbloed wheels and 315mm Yokohama A052s on the C6 - as well as some 295mm Hoosier R7s, but that Hoosier test was a hot mess, which I will explain.



We pick up here after Track Test #7, which was on April 28th, 2022 - where a 16 year old stock rubber front control arm bushings popped out. But first, I had a bit of an epiphany with respect to "what should we do with this C6?", specifically, what class should we build it around? I found a surprisingly good class to run it in a rather surprising series. And even more shocking - I won the first TT event we entered, by a healthy margin. Let's get started!

PICKING A TIME TRIAL SERIES & CLASS FOR THIS C6 : SCCA TT TUNER 2

After being out of the Time Trial game for nearly 3 years I was really missing some form of Motorsports competition. Sure, I'd done a few autocrosses in 2020, 2021, and even a couple in early 2022. Below are two events I won this year. In the C5 I won my class and set FTD at left, and won the class and set 3rd fastest time of the day in thew '22 BRZ at right. So while I don't totally suck at autocross, the limited amount of seat time in these parking lot events wasn't "scratching that itch", even with some solid wins. What I really needed was some road course competition, and the most affordable road course events I have found over the last 30 years are Time Trials.



If you have followed my social media and forum posts for a while you would know that over the past 15 years I have trended away from autocross (which I started in 1987) and towards Time Trial events (I did my first TT events with NASA in 2006 and other groups as far back as 1991). While I will always be an autocrosser at heart, and will continue to compete there, for business reasons and my personal driving skill set (or lack thereof) I think my time is better spent doing Time Trial.



My "go to" TT series NASA has over the last 15 years become much more focused around Hoosier DOT tires as the the basis for all TT classes, from TT1 to TT6, and showing up on 200 TW street tires will get you relegated to "class filler". I did two seasons of events with NASA Texas (2018 and 2019) in my '18 Mustang GT (above left) on 200 Treadwear street tires on Day 1 and would switch to Hoosier A7 and R7 tires on Day 2 of a NASA weekend. The difference in times was always around a second per lap, but I noted that without aero and gutting the car to get on the edge of the Power-to-Weight ratio, I was largely uncompetitive in NASA. On the other hand, from 2012-15 we ran our 2011 Mustang GT (above right) in NASA TT on the max width Hoosier A7s, with full tilt aero, and at the edge of the power-to-weight ratio - and dominated TT3 class, setting 16 class track records. NASA TT is really geared towards the super serious, not dual purpose street/track cars like this C6.



And while NASA has tried to offer parity with some "tire equivalency" power-to-weight modifiers for TT in 2022, it is virtually impossible to do this right. The breadth of grip levels within "200TW" tires is huge, and the difference between 200TW and R7s is also pretty large. We have seen 1.15g on the R-S4 and 1.30g on A052s, both marked and classed as 200TW tires. Hoosier R7s and A7s tend to make closer to 1.4g grip, which is another step up. NASA has seen unintended secondary effects from their "tire modifiers" in TT that added even more class instability and cost.

I'm not willing to play that game at the moment, especially with a legit street legal car like this C6 - which I have promised my wife and crew at Vorshlag that we will NOT do the following to: cut up, add aero to, gut the interior of, add a cage, or swap the engine. This was supposed to be an easy "tweener" track car build, to allow Amy and me to have some fun track time while our REAL cars are being built: her '13 FRS and my '15 Mustang. It has already gone past the "easy" but it is still streetable with a full interior, functional emissions, cold air conditioning, roll up windows, and yet monster improvements in suspension, brakes, and more.

The sad truth was that the lap times in this little C6 were pretty uninspiring on the 275mm R-S4 200TW tires, and the bone stock 360 whp engine was a little underwhelming as well. So after we tackled the troublesome ABS issue and got the MCS coilovers on, I started looking at places to race this in Time Trial. Looking at the power and weight of the car (3320 pounds with driver + 360 whp) it was pretty much doomed in NASA TT classing - just like my 2018 Mustang, it was it was stuck DEAD in between their TT2 and TT3 classes...



Each NASA TT class has a strict power-to-weight ratio you have to build towards - TT3 is 10:1 while TT2 is 8:1. Like the 2018 GT, this C6 was stuck almost exactly at 9:1, right in between two classes. I spent 2 years trying to get around that limitation in the red Mustang, jumping between TT2 and TT3, and was largely unsuccessful and frustrated. I found once again that to be competitive in NASA TT you have to CUT ON THE CAR to fit max width tires, GUT the interior to get the weight closer to the P-to-W limit, add REAL AERO that wrecks the streetability, and of course RUN HOOSIERS in widths that will cost $500-600 per corner.



Of course you can always "aim lower" and build towards a slower class. We could have run this C6 on 275mm wide Hoosiers and either ballasted up with weight and/or detuned the 360 whp engine to make the 12:1 p-to-w ratio required to run in TT4. But I've already done too many seasons in "slow TT cars", with my E46 330Ci (in TTD and TT4) and C4 Corvette (in TTC), above. I just don't enjoy driving slow cars, even if they are "more competitive in class."

So I wasn't down with making this C6 even SLOWER to fit within TT4, then running $2000/set R7s that would wear out more quickly because they were needlessly narrow. I know we can fit 315mm tires under the stock narrow body fenders, and by damn THAT IS WHAT WE WILL RUN. And I know there is some easy power we can unlock with headers and a few bolt-on tweaks, and I want to DO THAT TOO!



I had written an article in 2018 about SCCA Time Trial rules and suggestions (linked here), but I have updated my thoughts on that series in 2022 in this post. While I was a critic in 2018 when SCCA National first rolled out their new TT series rules, they have made some significant improvements over the last 4 years - and more pressing, my home SCCA club Region adopted the National TT rules for 2022. So while I had fun and success in my 2018 Mustang GT and the FRS running the regional SCCA TT (see above) for a few years with their unique Regional rules, if I wanted access to proper 200TW based TT events locally (Texas Region does 7-9 events per year - at tracks all local to me!) I would have to adapt to the National SCCA TT rules.



So we dove into SCCA's TT rules in 2022. SCCA TT has 4 categories: Sport, Tuner, Max and Unlimited, with classes within each. The base Sport category is far too stock for my tastes or our business, Tuner was like Street Touring autocross classing (which I ran competitively in from 2004 through 2013 in many cars, including the two above), Max was pretty wide open but still 200TW based, and Unlimited was anything on Hoosiers or other mods beyond Max. Due to some wild price increases with Hoosier during the Pandemic I am going to largely stick with running 200TW tires for a bit. And while Max looks like fun (full suspension, aero, gutting, flares, cages, and virtually unlimited power upgrades), I am trying to keep this C6 a street legal car and again, not cutting / gutting / swapping engines. Maybe one or our other cars being built will run in Max.



After weighing the 4 possible categories we picked SCCA's Tuner category for the Corvette, and the class where this narrow body C6 fits is called T2. T1 is for widebody C6 Z06 cars, and pretty much all non-supercharged narrow body C4/C5/C6/C7 cars go into T2. The T3-T6 classes are all for less powerful cars. Each class in Tuning has a Max tire width, and in T2 it is 315mm, and of course 200 TW tires. I have been doing a LOT of testing and driving on 200TW tires for the last 2 decades, so that fits. Mods allowed include common bolt-ons like headers, exhaust, cold air intake kits, seats, wheels/tires, big brake kits, and pretty unlimited suspension changes.



Luckily almost everything we had done to the C6 was all legal for Tuning 2 class, and the rules committee was open to making some allowances if you had good arguments. Like the transverse leaf to coilover swap - it wasn't legal in Tuner until after I sent a letter and made a case for precedent from SCCA Street Touring autocross class, which had allowed this swap several years earlier. And then the TT committee made a change within about a week - that was refreshing! One limitation in Tuner is around bushings - metallic busing replacements are NOT legal, like the Street Touring Solo classes, which influenced the decision below... (probably for the better)

CONTROL ARM BUSHING FAILURE & POLY UPGRADE

After track test #7 it was clear what failed, but unclear on which way we would go from here. We got to work on the fix right after that test.



There was one upper control arm bushing that had pushed out of the sleeve under heavy braking on the not grippy R-S4s, and this would only get worse the more we ran with grippier tires on this car. Replacing one bushing with another OEM unit would be beyond foolish, as this is a very common failure. We have had customers who tracked their C6 cars that had multiple OEM bushing failures when new, and replaced them repeatedly under warranty. The "common" fix is to swap to spherical bushings on all of the rubber bushings.



I spent entirely too much time looking at these options, as "everyone on the internet" goes with sphericals to replace the rubber bushings. Two grand for the spherical bushing kit and it is a LOT of work to install these, often including a step to send the control arms to the manufacturer to have them honed to precise size. The sphericals were not legal for SCCA TT Tuning class, so that option was out - but I didn't want to use these for other reasons. The Delrin bushing kit from Ridetech would be legal but at $1400 it is still as much work and likely will make the ride quality as bad as the metal sphericals.

The downside to both of the above options is increased NVH (noise / vibration / harshness) and a RAPID wear and replacement cycle. We had a customer stop by in his C7 last month who had been chasing a very loud rattle in his C7, which had spherical bushings that replaced the OEM rubber units. It took about 30 yards of driving for me to isolate what had happened. I got out, popped the left front tire's sidewall with my fist - BANG! BANG! BANG - and showed him how to replicate the noise. Yea, the sphericals were worn out after one year of use. The noise was LOUD. You see, unlike the sphericals we use in top mounts, Corvette control arm bushings are MUCH closer to the ground. As such, the unsealed metal spherical control arm bushings get sprayed with water/rain and mixed in with that is grit and sand. That EATS metallic bushings FAST. Luckily, Tuning doesn't allow this, so polyurethane or Delrin were our two options.



To keep this C6 from turning into a "miserable to street drive" car, plus the Tuning class rules, and due to the fact that the C5 above (that I have driven many times) got polyurethane bushings that we installed SEVEN years ago without issue, I went with the same Energy Suspension bushing kit we used on that car (the C5/C6 bushings are identical). The Energy Suspension bushings for the C5/C6 come in two colors (red or black, no functional difference) and there is a kit for the front (ENS-3-3176) and another kit for the rear (ENS-3-3177). All in you are looking at about $150 for all of the parts.



Normally I go for the RED to show the bushings better in pictures but that color was out of stock, so we went with black (add an R to the end of the part number kits above for Red, add a G for Black). They come with some small packets of grease but I'm going to show you a trick to make these poly bushings SQUEAK FREE for life - it involves adding grease zerks to each bushing.



This section of "installation tricks and tips" for the poly bushings got so huge that I pulled it out into it's own post, which you can read here. I recommend that if you plan to own a C5/C6/C7 Corvette. Long story short: any bushing upgrade is a pain in the ass but Poly has the least downsides and lowest cost (by a factor of 10), and this upgrade has been flawless for months of track tests and Time Trial events since.

NEW BALL JOINTS & CORNER BALANCE

During the control arm bushing upgrade above, I noted that several ball joint boots were cracked and falling apart. None of the ball joints were "bad" yet, which is why it was never noted in our pre-track inspections (where we wiggle and shake ball joints and wheel bearings), but it was time to replace several of these. Tracking the right part numbers down took a little time, and we had to order one of these twice - which set back my track testing schedule. See, I was eyeing an SCCA Time Trial at ECR on June 18th and this was pushing out my timeline.



With Jason's help we tracked down the right ball joints and Doug was able to replace all of the worn ones. Couldn't find just replacement boots, which is all most of these needed, but we replaced just the bad ones and moved on.



I picked Moog replacements, which is a brand we have used many times and trust. There were two front upper ball joints, one rear lower ball joint, and one tie rod that had a burnt boot.



These are usually changed with the control arms out of the car. The old ball joints on the C6 did NOT have snap rings retaining them in place, but some cars do. These just pressed out and the new ones pressed in. Doug used this massive C-clamp style ball joint press on some, and others were pressed in/out using out 30 ton air over hydraulic press.

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With the all important ball joints installed (below left), the arms could be reinstalled. These Moog replacements have an actual grease zerk for regular greasing, unlike the "sealed for life" OEM ball joints.



With the ball joints and bushings replaced it was finally time for the car's first Corner Balance, which we skipped after the MCS install due to track test scheduling and time.



Brad dialed in the corner balance on the morning of 5/17/22 using our digital scales and 175 pounds of ballast sitting in the driver's seat. He got the cross weights to 49.91% & 50.09%, which is pretty dang good (within 0.1% is as good as want to shoot for). The wacky thing is that the C6 weighs exactly the same as when we did our initial baseline stock weighing - 3117 lbs. It now has wider wheels and tires, bigger brakes, huge radiator, and some other upgrades. A little less fuel this time, though.

FITTING 295/30R19 HOOSIER R7 TIRES TO THE CAR

Right after the MCS coilovers were installed, a bit earlier in 2022, I asked Brad to test fit these 19x10" wheels t the C6. I assumed the wider 295mm tires would require some spacers to clear the shocks, and yes I know that this 295mm width size is "too big" for a narrow 10" wide wheel. But it was an extra set of very inexpensive 19" wheels I had for this car that we had set aside for this set of R7s long ago. In a perfect world these tires would be mounted on a 19x11" wheel, but that size wasn't available at the time for anywhere near what I paid for these 19x10s.



I also bought these Hoosiers for $300 for the set. Yes this set of Hoosiers should have been $1600 new in 2021, but I got them for a steal - after sitting for 3 years in storage I scooped up this "sticker new" set for a song after seeing them posted on FB marketplace. The long wheel studs that were installed on each corner would allow us to slip on some spacers as needed. It took a 1/4" spacer at each corner to make these work, nothing to worry about and the tires still easily cleared the fenders, as seen below.



I actually had these Hoosiers with me to use at both Track Test #6 on April 14th and Track Test #7 on April 28th, but unforeseen issues at both tests (rear brake pads disappeared at Test #6 and the control arm bushing popping out at Test #7) cut those test days short without any "Hoosier Laps".



Now that we had those issues fixed we could take then for Track test #8 - or so I thought...

BSP MOTORSPORTS ALIGNMENT - MAY 17-18, 2022



I called BSP Motorsports, a local motorsports install and alignment shop, and begged them to sneak my C6 into their alignment schedule. They got us in the same day that we finished the corner balance. The C6 was in and out in 24 hours and dialed in the maximum camber they could get with the stock eccentric adjusters up front, then balanced with an appropriate amount out back.


I was disappointed that even with this ride height on coilovers, all we could get was -2.3 deg camber on the left front (right front could get to -2.8, but again - had to balance to the low side), so that was what it was set to. The rear was set at -1.76 camber to balance the rear to the front. I asked them to set the front toe to "zero" and the rear to 0.28 deg toe in on each side (1/4" of total toe in). They got this dialed in, verified our corner balance, and I picked up the car with the trailer and loaded up that night to go to the track the next day...

TRACK TEST # 8, MAY 19, 2022

With the C6 loaded up I left at 5:30 am to head out to a Thursday member day at MSR Cresson. I was excited to finally get a session on the R-S4s with a proper alignment and the coilovers and bushings fixed, but also to run a session on the 295/30R18 Hoosier R7s. I had an outside hope of taking the C6 on these Hoosiers to a NASA TT event in early June at nearby Hallett, if the lap times looks halfway decent and the car felt sorted.



That was not what happened. I was the only car on track for the first session of the day, but I was fighting weird braking issues that were completely out of character for this car after we had sorted the ABS. What is going on on NOW?



After taking 3 thirty minute sessions and 24 laps on the R-S4 tires, I was not getting any faster. These 200TW tires just were not giving me much grip. After a string of high 1:24s I managed a 1:24.1, then a 1:23.4, then strung together a new personal best of 1:23.39 on the C6 with MCS RR2s, 275 RS4 tires, and new poly bushings.



I had a 60 minute delay during which open wheel cars and motorcycles ran 30 minute sessions, so I came in and started swapping onto the the 295mm R7 tires with the marked spacers. Didn't see anything weird (apparently I'm blind) as these went on then I was ready to go out at 10:30 am for a five lap stint. I needed to go out, scrub off the mold release, come in and check pressures, then do another quick stint to maximize lap time on the Hoosiers.



Right away I noticed an issue - after installing the R7 set the brakes didn't want to work, at ALL. Every time I stepped on the "whoa" pedal the ABS went into some weird hysterics and it wouldn't slow down. Was there a bad wheel speed sensor? Had the Mk60 gotten into its own sort of "ice mode" that I didn't think was possible?




It was getting warmer and my chance of running that "gold lap" on the R7s was dwindling. So I stayed out and limped the car to a new best lap of 1:22.933 lap, essentially not using ANY brakes. Then when braking into T9, the RF tire locked up briefly. Whoa... that was weird. I decided to come in, but I had just passed Pit In. So I limped the car around and at Ricochet I touched the brakes, and the right front tire locked up and stayed locked. I couldn't drag the tire around locked up like this, so I drove off the corner and parked it off the edge of the track in the dirt. The track workers had to send truck and trailer out and drag the car up onto the flat bed with a board under the RF tire. The brake would NOT unlock!



After unloading the car with the tire still locked, I quickly got to work trying to figure out WTF was going on. As soon as I jacked up the RF corner, the tire unlocked and spun freely. Removing the wheel it was then obvious that the front brake flex line was pinched between the front spring coils, and from the looks of the line it had happened many times before. This time it caught it just perfectly and once I applied brake pressure it locked that corner's caliper, hydraulically.



Once again the RoadKeeper camera had no audio on all video taken, so it is worthless. After I removed the brake line from the spring I drove around the paddock and it stopped fine, but that one Hoosier was trashed (now these cost $500 each) and I loaded up and headed to the shop for repairs. This was a complete sh!tshow of a track test.

BRAKE LINE REPLACEMENT, TIE ROD HEAT SHIELDS, CARBON LIP REMOVED

Later the same day as Track Test #8 I unloaded the C6 and we put it up in the air to diagnose what went wrong. Clearly I saw the pinched brake line but the ABS trouble light was on as well, so I asked Doug to connect the Mk60 to his Matco scanner.



With the ABS connected to the scanner he noted the usual logged errors - steering wheel sensor, VIN number issue, and CAN disconnected (which we have had ever since the Mk60 install) but there was also a logged error for a RF wheel speed sensor. That was likely from when the RF wheel locked due to the line being mechanically pinched. So the Mk60 noted it, which is good to know.



I had noted that the LF wheel hub that felt a little sloppy during my swap at the track to Hoosiers, and Brad also noted it. This was the non-SKF branded active hub we had on the front, so I ordered another SKF.



That took a week to arrive but we got that swapped out a couple of weeks later. Now the car would have 33 spline SKF X-Tracker hubs on both fronts and 30 spline non-SKF rears. I am still planning to upgrade the rears but I will have to buy 33 spline axles and swap those at the same time. Again - learn from my mistakes and if you are upgrading to a Mk60 and need the Active hubs, just buy all four up front (and swap the axles if you have to) and save yourself these troubles. Being cheap always costs money!



The brake line was once again pinched in between the spring and the upper perch, as I drove the car in. I guess this is a possible downside to converting to coilovers from transverse springs - there is no factory bracket to keep the stock line from touching the shock because they don't have a spring there. It keeps wanting to flop over that way on the RF corner, and it likely had a slight twist in the flex line that made it want to lean that way. So while we could have just twisted the line to not fall into the spring, I wanted to fix this right.



We also burned another tie rod. This is happening because we are seeing alarmingly high front brake rotor temps, approaching 750 def F, and the tie rod boot is very close to the rotor on these cars. So we ordered another new tie rod and I asked Brad to make a stainless steel heat shield. We keep 316SS sheet on hand for these things and it was a relatively easy design to cut, bend, and install between the tie rod nut and the spindle. Now we have an air gapped shield using metal that does not like to transmit heat.



A pair of Stoptech stainless brake flex lines were ordered and Doug made this little "deflective cover" out of aluminum sheet (softer than the line's jacket) that is clamped to the upper control arm. This will keep the line from getting into the spring again, but shouldn't damage the stainless flex line. We are keeping an eye on this every time the wheels are off, of course.



The brake rotor temps I logged at the last two track tests were really high up front, and it was obvious why - the Extreme Dimensions carbon fiber front lip was blocking the factory front brake inlet ducts. This lip was also quasi-illegal for SCCA T2 class, so instead of trying to modify this unit I asked the guys to remove it.



This is now how the front brake cooling flow should work, instead of the tortured and half-block pathway that the splitter lip caused. This also allowed us to reinstall the OEM air deflectors on the sides. I will continue to take IR gun temps from the rotors and should see a significant drop in temps by removing this - but could also see lower front downforce. We will see.



It was also time to install the Jongbloed 18x11" front and 18x12" rear wheels. These went on with a used set of Yokohama A052 tires in 200TW, but in a wider 315/30R18 size. I purchased these tires in 2020 to use on Koenig's C5 for the Optima autocross event but the durometer readings were still good and they only had about 5 autocrosses on them by this point.



And while I had planned to modify these nozzles on the factory brake cooling at a later point, the wider and taller 315/30R18 tire was rubbing the plastic here when the wheels were turned, so I asked Doug to lop these off. This gained clearance for the tire when turning AND possibly opened up the airflow from the brake cooling.



We ordered these max-fitment wheels a year ago, long before the coilovers were installed. The measurements were fudged with the expectation we'd run a small spacer to perfect the fitment.



At the end of the day on May 25th I loaded up the C6 with the Jongbloed wheels on for the first time. Sure, I should have left the "control tires" (19x10/275mm R-S4) on the car to get a proper updated lap in, but damn it I was tired of the slow ass Hankooks. They take too many laps to get up to temp and they just don't ever make more than 1.15g lateral. I'm ready for more grip, but the Hoosier set had that one flat spotted tire. So the 315mm Yokohamas are the new control tire. Let's see what they can do!

TRACK TEST #9, MSR-C, MAY 26, 2022

Only one week after Track Test #8, and ALL of the repairs and updates shown above, we were back at Motorsport Ranch Cresson for test #9. After the previous two track tests were scrubbed early due to parts failures, I really was looking forward to a less troublesome day. I also had two customers meeting me at the track, one to test drive his Cadillac daily driver and the other one was the new owner of my 2018 Mustang GT, who came back to have us T56 Magnum swap the car (along with many other upgrades). I was there to make sure the car was working well on track after a bunch of changes we made. I include a "guided track day" for every major build we do, and even though this one was a bit less than "major" I still wanted to be there to diagnose any issues and/or do some coaching at a track he had never driven at.



I arrived before 7 am and had the 7:30 am session all to myself. I fueled up the tank for several sessions and went out before the track really had a chance to warm up. I broke up each 30 minute session into two stints - because the tires were overheating after 3-4 hot laps. I was also adjusting tire pressures and checking the brakes, since I had such problems the last two track tests with those. I came in quickly after my first stint (1A) and jacked up the front to look for any tire rub, nothing worth noting.

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The two stints in the first session were all pretty cautious, listening for tire rub, feeling out the brakes, tweaking pressures. I a 1:22.759 but way out on my 4th lap of that 1B stint. The tire height was shorter than the 19" Hankooks and this required me to alter my shift points and made 2nd gear pretty much useless.



Stint 2A saw a 1:22.7 then a 1:22.3, then I came in the hot pits to alter tire pressures and let them cool off a tick. I went back out in 2B and ripped off a 1:21.9 and a 1:22.0 on the first 2 laps in the video linked above. I was still feeling out using 2nd gear in Rattlesnake vs 3rd, and it was pretty much a wash.



Lateral grip levels of 1.3g were much higher than before on the Hankooks (1.15g), but braking loads were still stuck at 1.15g (and still are to this day). I was happy with the 1:21.926 lap and saw a 1:21.7 predictive. I was also happy to have a track day without any "incidents". Braking still not exceeding 1.15g but lateral was 1.30/1.37g, so we're definitely needing more aggressive pads and/or better calipers. G-LOC R16s are inbound, so we'll try that next before throwing bigger money and/or time at a "Big Brake Kit" solution (the "cheap" front AP upgrade is $2500 nowadays).



Jon showed up with the Mustang after my second stint and we got him all signed in and ready. I took him for a ride along in stint 3A in the C6, then did some "lead follow" laps in stint 3B (which is why the times were slower). I then rode along with Jon in the Mustang using my helmet-to-helmet comms trying to get him acquainted with the track. We broke for lunch around 11:30 and I was loaded up and out of there by 12:30, but Jon and Dan stayed out for most of the day taking laps.



Dan was able to snap some pics of the C6 in corners, and these two show me that we need MORE NEGATIVE CAMBER and there is a LOT OF BODY ROLL. So some sort of camber kit is needed, as are aftermarket swaybars. Jason and I began researching options for these future upgrades later that day, back at the shop.

The brake cooling improvements were significant - after removing the "ZR1 lip" and un-blocking the brake inlets (and opening up the "nozzle" inside the wheel well), the front rotor temps to came from 750 F (at the last track test) down to 505 F (shown at the end of the in-car video above), which is huge; rears were stable at 400-450F. Just still not enough braking force on the friction circle to my liking. I am used to braking much later in corners in my old 2018 Mustang GT, which was 3900 pounds with driver (600 more than this C6) but it had Ford ABS and a big brake kit (it would make 1.3-1.4g stops). Still, it was nice getting into the 1:21.9 lap time range, but I felt like these tires should produce more lap time drop than that. Was hoping that with more camber and better brake pads we could see another one second drop on these same A052 street tires.

ABS PLASTIC FRONT LIP (FAIL)

After removing the carbon lip I began looking for an option that was both legal for SCCA Tuner class and that did not block the brake vents. There are SO MANY options out there and most of them for the narrow body actually do what this carbon lip did - they have the brake inlets set at the wrong width. I searched high and low and found a somewhat affordable ABS plastic lip (legal for Tuner) that looked like it was actually made to fit the narrow body C6.



This did indeed have right style inlets built into the lip that lined up with the brake inlets - that was a plus.



We did a quick mock-up on June 1st and it looks like it might fit? The side air deflectors once again have to come off to fit this up properly, which Doug tackled that day before diving into the header install shown below.



When the exhaust work was wrapping up a week later it was time to mount the ABS plastic lip for good. Now it was obvious that this part was a giant hunk of crap. While the brake inlet ducts did line up, the floppy plastic piece didn't fit the contours of the front end at all. After fighting with this for an hour and seeing that it was never going to fit properly, I threw this thing straight into the dumpster where it belongs. DO NOT BUY THIS JUNK. Just not worth the hassle.

PADS, ROTORS & A FRONT HUB

The 1.15g stopping data didn't impress me at Test #9 with the Yokohamas so I figured now that we had the ABS and brake cooling a bit under control it was time for a more aggressive pad.



We had ordered these R16 fronts and R12 rears, which was a single step up in track compound aggressiveness from the pads we had been running. And never wasting an opportunity for product pictures I shot these sets in our studio and put them on the website in place of the "generic" pad pictures we had for the C5/C6 PBR caliper pads.



The R12 fronts had seem some real abuse over 8 track days, and the drilled rotors were wearing these very quickly. The rears looked pretty good after 5 track days, due to the fact that the front brakes usually do 80% of the stopping work + some brake bias issues.



This C-Tek branded active hub had started to fail after one track test, and we had ordered this X-tracker SKF for that - now it was finally installed. Aaaand the speed sensor was bad. So now instead of just checking Ohms for a new speed sensor before we push in the long wheel studs and it is installed, now we hook up the Matco scanner, plug in the speed sensor, and turn the hub before we put them on. Sheesh...



So another SKF was ordered under warranty and that went on along with "smooth" rotors. No more cross drilled holes! We had to search around and pay extra to NOT get the dang cross-drilled holes in the fronts, but we found some from Centric. Of course I weighed them, and this should slow down some front pad wear. The rear rotors were left alone - the rear pad wear was already too good to worry about that.



Doug got the smooth front rotors installed, the second SKF bearing put in worked, and the front and rear G-LOC pads. The system was bled with fresh RBF600 Motul fluid and the brakes were ready for the next track test.

HEADERS / EXHAUST / COLD AIR / THERMOSTAT

This round of exhaust work happened later than I had hoped, with as much time we lost with the factory ABS issues, then the weird part failures at multiple track tests, but it was now time for more power.



I always like buying high quality, American made, properly designed, and well fitting stainless exhaust headers - usually from American Racing Headers, which we are a dealer for. I have purchased their 1-7/8" primary / dual 3" exhaust with a catted X-pipe systems for my 2011 and 2018 Mustangs, and they both fit great and picked up a big bump in power. Doug here at Vorshlag had a set of used stainless headers that came off of his C6 Z06, with the X-pipe, so I figured... well, they fit his car, and they were 1/10th the price?



Again, not what I would normally recommend or use, but we had a narrow window of time when the car was on the lift doing the brake pad / rotor work above, and Doug sold me these headers for almost free. I don't even know what brand these are, and I figured if they fit poorly or the performance wasn't there, I would punt and get the ARH versions - as there shouldn't be a lot of time and money invested.



The factory log style exhaust manifolds were pretty bad looking, so my prediction of seeing 25-35 whp peak and 30-50 whp mid-range power boost with long tube headers should hold true here (that did not happen).



These random import headers did fit the LS2 C6 well, surprisingly. They aren't pretty, but again, for this car they should work well enough.



Well the first thing that didn't fit was the X-pipe and mufflers, which were factory dual 3" for the Z06 / LS7 engine and dual 2.5" pipes on the LS2 engine. My mistake for not knowing that the LS2 came with smaller stuff. Looks like an excuse to upgrade the mufflers!



Doug found a pair of used C6 Z06 mufflers and pipes on Facebook marketplace for a few hundred bucks. These OEM mufflers have vacuum controlled "active bypass" valves that default to open, which is how we installed them initially. We will go back later and scavenge the factory Z06 vacuum canister & plastic tubing from my 2007 Z6 in the barn then put these on a switch to be able to quiet the mufflers down for street use.



The pair of stock LS2 mufflers were 10.4 pounds lighter than the Z06 mufflers, so we wiped out all of the weight drop gain from the manifolds to headers. Again, not what I had planned for this car, but these were available the same day and we didn't lose any time within this narrow window we had open on the lift.



The next thing that didn't fit, once the 3" LS7 mufflers were installed, was a missing piece of the X-pipe exhaust kit. Doug seemed to have lost these rear pipes, so I had him fabricate this 2 foot long section with mandrel bent stainless to join the headers and X-pipe to the LS7 exhaust. And add V-band clamps to that junction. Nearly two days of fab and welding later, and yea... I should have bought a new set from ARH. It costs money being cheap!



Back in 2021 I searched the entire internet for an aftermarket cold air kit to fit the short run 2005-07 LS2 C6 Corvette. Did not exist. There were plenty of options for the 2008-2013 LS3 Corvettes, so I bought this SLP C6 LS3 cold air inlet + filter kit - hoping it would fit this LS2 car. It did, and has more airflow potential than the stock airbox, but it did take some trickery to make it work. We had to switch from the LS2 style MAF sensor to an LS3 style MAF, but I will talk about that in the next section.



The filter and tube all fit, but the front mounts for the filter mounting bracket that was included for the LS3 car was off, so Doug redrilled those holes and added rivnuts to fit the LS2 car.



These rivnuts then helped these rubber nipple mounts that fit into the SLP air filter. As an experiment prompted by Erik Koenig at HPR, we pulled the stock 205F thermostat and installed a 180F. That lowered the coolant temps to 201F in the car, down from 210F.



The old spark plugs came out (they looked fine) and were replaced with NGK BR7 plugs. We also added BBK O2 sensor harness extenders, which is common for long tube headers.



I'm a little embarrassed that I didn't splurge for new headers, but overall the finished result was nice. The exhaust all tucks up into the tunnel and has the same ground clearance as stock. I don't love the ball-and-socket collector flanges, but I didn't want to invest the time to replace those with V-bands on a cheap set of used headers.

CUSTOM DYNO TUNE (LGM) + WIRING FIXES



On June 7th the folks at LG Motorsports had scheduled a slot to dyno tune our C6. The goals were simple: to fix the tune to work with the new exhaust + LS3 style MAF swap and get us a conservative "road race safe" tune. That is very different than a "drag race" tune, or a simple "street tune". When you spend 20-30 minutes at wide open throttle, the tuning needs change drastically over drag or street tunes.



The owner at LGM is Sergio, who is a well known tuner for HP Tuners, AEM and Motec systems. He was going to use HP Tuners to clean up the EFI tune on this C6 to make the LS3 MAF work (we did the wiring adapter - just needed some programming changes), and give us a 93 octane safe road race tune. They work on Corvettes almost exclusively and they are only 15 miles from my shop. I unloaded the car on the 9th and let them do their thing.



Two days later the car was ready, and was running great. I was disappointed with the gains, however, as it made 360 whp SAE bone stock, on True Street Motorsports' 248 series DynoJet chassis dyno. To only gain 22.5 whp with a cold air, long tube headers, a full 3" exhaust and a custom tune seemed down, but Sergio explained that his DynoJet 248 series dyno tends to read lower than others. Or was it the cheap headers we installed? Or not enough timing? I was second guessing everything at this point...



Sergio had done a good bit of street / driveability tuning as well as dyno tuning. He said there was some tuning funkiness that only showed up in 2nd gear pulls on the street; with enough acceleration something was losing contact. After shaking and wiggling harnesses it turned out to be the LS2-to-LS3 MAF adapter harness from Casper Electronics that I purchased. He had this connector zip-tied together to keep the contacts together for the remainder of his tuning, but once back at Vorshlag it was easy to see. Doug got to work repairing this.



We ended up buying a new connector for one end and Doug re-pinned all of the wires to make sure they were inserted fully. That fixed the issue and it hasn't cropped up since. I still think we are missing horsepower somewhere - I don't know where, but I'm going to keep looking.

BRAKE COOLING "SCOOPS", 2ND SEAT, FIRE BOTTLE, SEAT HEATER & CAGS BYPASS

This round of work happened right after the dyno tuning and just before the June 18th SCCA Time Trial. I had missed the NASA TT event the week before due to scheduling slip, but I don't think this car would have done well in NASA TT3 (it is several seconds off the pace with no Hoosiers for that series). Instead we would concentrate on the SCCA TT event prep, and hope that I don't get trounced...



The flat round opening in the lower plastic panels that feed the brake cooling duct were pretty sad. They only worked due to having the air dam wall behind these openings, but those really make it hard to run the straps to the front wheels every time I trailer this car (30+ times and counting!) I had envisioned these mini-inlet scoops in a dream, but we had made something similar on my C4 Corvette and they worked great. Jason and I spit balled some ideas then I worked with Doug on the template in cardboard, that he then turned to aluminum sheet and formed int he roller.



The overall size was minimized from the initial prototype and these barely stick down below the flat undertray, and above the bottom of the air dam section - so no loss of ground clearance. I was hoping for longer stints to be possible, as the SCCA TT at ECR coming up was on a course direction and layout I had never done - so I would need to run the entire 30 minute front session on the R-S4s to learn them.

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Now it was time to tackle the second Corbeau seat install and harnesses. I had foolishly been driving the car for over 14 months at this point with the stock 3-point belts. The support from these tilt back Corbeaus was better than the stock seats, but harnesses would still help.



We then dug up the original CAD files for the final bottom mount C6 seat brackets Zach made for the driver's seat, so we could make another set for the passenger seat.



Initially I asked Doug to install the passenger seat without the slider, and it did sit much lower - but the seat bottom cannot go back far enough at that low height and your knees end up in the dash. That would not work, so the quest for more headroom continues...



This car still has functional airbags, and I don't want to lose that safety feature. I also don't want to lose the "trigger" sensor in the bottom of the passenger seat, which turns off the passenger side airbags if nobody is sitting in that side. Doug removed this big white plastic sensor pad and slid it under the springs of the Corbeau seat, just like on the OEM seat. That way all of the factory wiring could be connected.



The anti-sub and lap harness belt anchors were added to the rear bracket, just like the driver's side. And the Safecraft 6-point harnesses were added to the passenger seat - with the sliders - before it went into place.



We also installed the hybrid 2" / 3" 6-point belts on the driver's side, using the harness bar installed ages ago. Now this would help a driver and passenger stay secured in the seats on track.



We had ordered the driver's side Corbeau seat with an optional seat heater, but never wired it up. Well since we had the driver's seat out to add the harness anchors, it was a good time to connect that. Doug added the Corbeau 2-position switch to the center console next to the ashtray, which we also modified to add a dual USB + volt meter gauge. The ABS trouble light is next to that. The seat heater now works and Amy is happy - she loves having these in every street car she drives. And with my back, so do I.



The seats are now both installed with the Safecraft harnesses and a functional seat heater. While these seats fit my butt and torso very well, I am lacking in headroom that just cannot be gained without sliding the seat further back. The slider has the travel but shape of the back of these Corbeau seats limits that additional rearward travel to the interior panels and console, so I am stuck driving the car with the seat back tilted excessively to gain the headroom - which is less than ideal. But again, this was supposed to be a car for Amy to drive, so I just grin and bear it.



As another nod to safety I wanted to add a 3 pound Safecraft Halon style fire extinguisher to the C6. This is not the same Safecraft company as the belts (although it used to be). This is an extremely well made part, with the handle and trigger assembly CNC machined from billet aluminum. Light years better than the cheapie Kiddie fire bottles I see in so many track cars, which often have plastic or stamped sheet handles and triggers. These Safecraft bottles can be refilled if you ever discharge them, and should be more reliable and have more volume to discharge than the cheaper Halon 2 lb bottles.



I asked Jason to design a small bracket that bolt to the factory passenger seat front studs. This .090" thick aluminum bracket was made to hold a with a Drake Offroad fire bottle quick disconnect mount. We then strap the bottle to the removable portion of the Drake mount, and it comes out with a simple pull of the red anodized handle marked "PULL".



We have put similar hand held fire bottles in dozens of cars in this same spot, even race cars with full fire systems. As we would see at this next TT event, sometimes you have a driving or car issue and have to pull off into the grass. There the hot exhaust can light off dry grass quickly. A little $250 or so investment in a 3 lb bottle like this, on a sturdy quick release mount, can save a car from going up in a small grass fire, or help put out a friend's car who is on fire. As always, let the track crew get to the scene of any fire and GET OUT of your car when it is on fire. But if its a small flare up, something like this can save you from a bigger fire. Hopefully I will never have to use it.



Last but not least is this CAGS bypass - that is a janky system GM used from the mid 1990s on for their 6-speed Tremec manual transmissions, which allowed the computer to force you from 1st gear to 4th gear on a low throttle upshift. Instead of grabbing 2nd gear you ended up in 4th, and it SUCKS. These "skip shift delete" kits were all the rage back in the day and I bought this a year ago, then finally found it and had Doug install it in this round of work.



The stock plug was a little melty, so when he went to put the bypass in I had him wrap the whole harness in DEI header wrap, then secure that away from the exhaust.

AMB TRANSPONDER MOUNTING, CLEAN UP, & ADD DECALS

The last things we needed to run an actual Time Trial were an AMB transponder + some class letters and numbers. But first, I did a full wash and detail on the exterior and engine bay...



After I got the brake dust and grime off the exterior and cleaned under the hood, I brought the C6 into the shop and Brad waxed the paint before the decals went on.



I won't get into it here, but I had started the quest for some class number/letter decals and Vorshlag logo stickers nearly a month sooner. Two previous suppliers both dropped the ball so I had to ask Doug to make these with his new CNC plotter he has at his place. There was a little miscommunication on the size of the number boards, so the "92" on the doors is big enough to see from space.



The transfer film that I had in storage for 5 years was badly aged, and I gave that to Doug to use. Brad and I tried to install the 2 layer number boards wet but had to call in the professional - Amy. She has patience I just do not possess, and over the next 24 hours of placement and drying she got them to lay down.



I took the car to get gas and the decals stayed on - success! We had the more than the minimum required "numbers and letters on both sides" with the addition of a front and back set, too. And some small Vorshlag logo decals.



Last but not least is the AMB transponder, which needed to be mounted "within 18" of the ground with no metal underneath". We found these MyLaps brackets from a random supplier for much less than most places, but I had to buy 4 to get a good price. They will come in handy for this battery style AMB transponder I have (my other is a wired unit). These stay charged for about 3 days so I needed to be able to mount this in a spot that was easy to access, but also without metal in the way of the transmitter. The left rear storage cubby under the rear glass worked perfectly - easy to get and only plastic underneath. Now its time to load up and go compete!

SCCA TT @ ECR 2.7 CW - JUNE 18, 2022

My experience with ECR goes back to when it first opened in 2008, and I ran there monthly through 2015 and still occasionally through 2018. I used to call this track home, and have 1000 laps here... "I used to rule these streets!" The thing is, I only ever ran the 2.5 mile course, and only ever ran it CCW. Well since 2018 this track changed hands and the new owner "started from scratch"... and changed the layout considerably.



Now the track is 2.7 miles long, with turns added from T6 though T9 and they changed T10 a lot. They also changed the curbing and run offs to allow the track to be run backwards - and that is what this June and the July SCCA TT events were running: the 2.7 mile course CW. I have ZERO laps on this layout and NONE in this direction. It might as well be an all new track for me. This is why we had the Hankook tires mounted for the first session - I fueled heavy and planned to run the entire session on these hard tires, to try to learn this new-to-me layout.

I was signed up for Time Trial, and the Texas Region SCCA had TT broken up into 2 groups. The faster folks were in the Red group and I was with the slower folks in Green. I took this as a bit of a snub and worried that I wouldn't ever get a traffic free lap, but the opposite was the case. This was the best thing that happened to me all day. With the big 2.7 mile course and a moderate number of entrants in my session, once I cleared a few folks that jumped ahead of me on grid in the first session, and was gridded by times for proceeding sessions, I had nothing but traffic free sessions all day.



Amy and Erik joined me for this Time Trial event, and I am glad because I really needed the help. This was a hot Texas summer one-day event and I got pretty dehydrated through the day. I was super nervous, not having run a Time Trial since August 2019, almost 3 years in the past. Almost nobody at this event knew me, as there had been a lot of "new member churn" during the Pandemic. A lot of the old racers haven't come back, so it is a lot of new faces.



When I got to grid for the first session, nobody knew that I set multiple track records on the old 2.5 mile layout, and when I asked the grid worker to put me at the front, she asked what I have run here... I said well, I used to run 1:55s on the old 2.5 course, but I don't know the 2.7 and I never ran it backwards. She moved me to P1 anyway, yet two other "regulars" jumped ahead of me on grid. Again, nobody knows who I am anymore, and heck... I could be slow AF...



And on the Hankooks I did feel VERY slow and only managed a 2:14 lap on my 7th hot lap, after I got around the two cars that jumped me on grid on the first lap. The tires just didn't make much grip in this coolest session of the day, but I needed to be out there the entire time to learn this track, and I got nearly 25 minutes of track time to learn. It wasn't nearly enough.



For the next session I had to swap to the A052 set, which should be 2-4 seconds faster. I wore my fire suit all day and was really sweating profusely, but Amy helped me change tires and we got the set swapped in under 8 minutes. Then made it to grid and parked in P1, due to having the fastest lap time in the Green TT run group by number of seconds.



Leading the group out I made sure to "bunch up the pack" so that I wouldn't catch the back of the field, then went "green" by Turn 3A on the out lap. This put me in clear sailing for lap 1, when I laid down a 2:09.542 before seeing a small grass fire and subsequent red flag 3/4 of the way through my 2nd hot lap, which was showing a 2:08 predicted time. We sat out there for 5 minutes while the track crew came out and put the grass fire out (the car had driven away safely after the smoldering started), then they brought us into the hot pits... after sitting idling for 10 minutes I was boiling inside the car and had to run the AC for a bit.



Then we went back out for 4 laps, but the tires were too hot to do better than a 2:11. That 2:09.5 was good enough for the class win but I was NOT happy, so I stuck around for after lunch - when it was 96 freagin degrees by then - to run session 3.



That session, starting at the front, on the A052s, and without a fire and red flag, allowed me to make a string of laps - still learning this course. My AiM showed a first lap of 2:11 (missing a 2-3 upshift), then a 2:10, then I did a cool down lap, then finally made a a hot lap 4 of a 2:09.19. The AMD loop showed a 2:09.396, and that was enough for the class win that day and 8th quickest overall for the event. I wasn't exactly thrilled but after a 3 year hiatus and being so lost I was happy. I was also massively dehydrated and I don't remember much after that...



The oil pressure CAN data stream was not in the video, due to a mistake in the video / gauge template I used - trust me, its not an issue. The video itself, well, I am hesitant to show this in-car video because my driving is so bad. I make numerous driving mistakes and never found the right braking points or apexes on a number of blind corners. I was so damned lost that I promptly went back to the shop and built a driving simulator just to learn this track for the following month - which made a HUGE improvement. But the next TT here had a lot more cars in T2 class, and some were a LOT faster.

WHAT'S NEXT?

I had planned to cover work after this June 16th TT event - we had Track Test #10 (with a new personal best for the C6!), a big change to the alignment, Track test #11 (a dud - the track was under construction and my laps were SLOW), we added new swaybars, the sim rig build and learning ECR, then another SCCA TT at ECR where we went faster on the same course.



I will coverall of that and more next time, but needless to say the C6 is getting much faster, easier to drive, and there are still things we can do in SCCA Tuner class that should improve things even more. I've got a few small tweaks left for power and will have the car re-dynoed soon to see if those changes help, too. Tune in next time for more crazy antics in our narrow body C6, #ProjectNewBalance!

Thanks for reading,

[Fair!]

Project Update for August 30th, 2022: It has only been a handful of weeks between forum thread updates but a lot has happened with our little C6 here and we have some real ground to cover. The C6 now has a little break until the next track outing so it is a good time to catch up.



In this update we will cover a "camber kit" we added along with new swaybars, then another Motorsport alignment, two more track tests (#10 and #11) at Motorsport Ranch, and two more SCCA Time Trials: Spoiler alert: this little C6 now has 3 TT wins in a row! I never could have predicted that last year.



Before the 3rd TT event in August we did another big round of work: fluid cooler updates and other leak fixes, underdrive pulley, oil/air separator, some brake caliper testing, we bought another set of 18x11" wheels that we thought would fit the narrow body C6, then a new shifter install and tested another seat. Let's go!

TRACK TEST #10 - JUNE 23, 2022

I went out to MSR Cresson on a Thursday morning to test the changes we had done in June which included: steeping up to more aggressive G-LOC R16/R12 pads, the long tube headers + Z06 dual 3" exhaust, cold air, and dyno tune (power went from 360 to 382 whp). I was hoping to improve upon Track Test #9's best lap of a 1:21.926.



I drug along Erik Koenig - engine builder at HPR and a friend of 30+ years. Erik took his first laps in 2+ decades in the C6, after riding along with me. He took 8 laps and had a ball. All testing this time were on the 2 year old Yokohama 315/30R18 A052 tires, as we left the "control" tires at the shop.



We drove the car over 4 sessions, but I put my fastest laps in the first stint. I managed a 1:21.127 best lap, but it was on lap 7 on boiling hot tires - These A052 tires work best on lap 1 in any kind of heat, but I couldn't get my brain in gear until lap 7. I saw a 1:20.6 predictive lap in there, but couldn't get it done. Saving that for next time!



The Vmax of 124.9 mph (see above) was a new high for this car, and 4.4 mph quicker than the Vmax at Track test #9 of 120.5 - the extra 22 whp must have helped. I think there is still a bit more power in the tune, as it was ultra conservative with only 20 degrees of total timing advance. I might go back after we add a few more parts and see if we can step on the timing a bit (we only ever use 93 octane in this car).



Koenig took some pics of me driving in the first session and I analyzed those for quite a while. There is a LOT of visible body roll (see above and in the section below) that we need to address. I can also see positive camber on the outside loaded tires in bog corners.



The video above is my best lap of the day, that 7th lap in session one. There are still a few nasty driving mistakes in there, but that's just how it happens some times. Not my best driving, but we found 0.8 seconds from test #9 to this #10 test, and there's a solid half second more in it (the 1:20.6 pred kept popping up). I had ZERO cars on track with me in the 1st session, so I have nobody to blame but myself. The temps were warmer than in May and would only continue to climb in July and August - I am thinking about a suit cooler.



I am still struggling with gearing - the slow Wagon Wheel corner is between 2nd and 3rd gears, and the quick Riccochet corner is between 3rd and 4th. I keep trying those both ways and do not know which is better - but the 2-3 upshift is still a challenge with the stock shifter, and we will need to address that in some way later.

CAMBER KIT + SWAYBAR INSTALL

At track test #9 in May we finally had the car aligned and the 18x11/12" Jongbloed wheels and 315/30R19 A052 Yokohama 200TW tires installed, and the C6 broke into the 1:21.X range with a best of 1:21.926 lap, then at test #10 we dropped to the 1:21.1. But the amount of body roll and loss of camber in corners was painfully apparent - this was slowing the car down and wearing the outer shoulders of the tires.



It was time to address both of these issues - with some research, trial and error, and even machining some custom parts before going for another alignment at BSP.

CHOOSING AND INSTALLING THE SWAYBARS

There are many swaybar offerings for the C5/C6, and we don't really get attached to a particular brand. We say we are "swaybar agnostic", and I mean it. Sure, if a certain brand has more adjustments, or better endlinks are included, or its a brand we know and have used (and can resell), we tend to go that direction. When it comes to C5/C6 swaybars, we had a few listed on our own website that we can get "wholesale" and resell. The smart move would be to go that route - promote what we sell!



Sadly the two brands we had access to - pFadt and Hotchkis - are getting really squeezed with supply chain issues. Hotchkis (above) has been in the weeds for 2+ years with some orders taking 6-12 months or longer to fulfill (we have cancelled / refunded virtually of those orders). The Hotchkis front and rear C6 bars were $540 and their endlinks were another $328. The front was 1.25" non-adjustable and the rear was 1.0" dia but at least added some adjustments. And out of stock "indefinitely" when we were looking to upgrade.




The Puff Daddy stuff is both out of stock and HEINOUSLY expensive - the swaybars and endlinks were $2100 + $500 for the rear pillow ball rear mounts, and all of that was out of stock, too! We have used their parts before (I took the pictures we have on our website) and they are very slick - splined hollow bars with billet aluminum ends, with a 1.50" dia front and 1.25" dia rear and plenty of adjustments at both ends. But at $2600 that is more than 13% of the purchase price of this car. This is a bit of an extravagant option for this car. Hey, if you have the budget, I recommend these, but this is supposed to be a "temporary" build for us. They are really just a hunk of steel tubing that twists - they aren't magic.



Back in June of 2022 I was at LG Motorsports for a little tuning work and dyno testing (which I showed last time) I went ahead and bought some of their G1 swaybars, both front and rear, and the optional endlinks. The bars were $780 and the endlinks are another $245, for a total of $1025. That's not out of line for hollow bars and adjustable endlinks, and the rear was adjustable (like the Hotchkis). They were also in stock - which our other two options could not meet.



Our base model C6 had some wimpy little bars, and the 50% larger diameter LG front bar should make for a big improvement in front roll stiffness. It came with new bushings and weighed 15.7 pounds. The stock front bar weighed 8.3 lbs.



The stock rear swaybar on our base C6 was a tiny little thing at .682" dia and weighing only 3.7 lbs. The LGM adjustable hollow rear bar weighed in at a meaty 8.0 lbs and measured in at 1.070" diameter. The endlinks looked beefy and adjustable. This install would be adding about 12 pounds, but getting the body roll under control should be worth it.



As with every swaybar install we do, we always measure for "pinky finger effort" to rotate the bar within the mounts. This video explains what we do and it is done to keep the swaybar from being bound up in the mounts. Almost every single aftermarket bar we have ever installed needed to be shimmed, trimmed, or tweaks to allow the bar to freely spin in the mounts - and this front bar needed some shims on the bracket shell to not bind. Brad knocked that out and installed the front bar with some good grease. It is a rubber bushing so we were not able to drill that for a grease zerk in the shells as with the polyurethane bushings that come in most kits. We will keep an eye on that and test for rotation any time the endlinks are off.



The rear bar was a tick easier - this one rotated freely without needing the mounting shells shimmed or tweaked in any way. That is RARE. Also greased the rubbing bushings and I asked Brad to set the adjustment on full soft out back ad I would tweak it at the track as needed to adjust turn-in (we changed it later to the middle settings).

ADDING MORE NEGATIVE CAMBER WITH A CAMBER KIT

Back in May when we did the poly bushing install, using the stock eccentric washers and bolts at the lower control arms we could only get to -2.3 deg front and -1.78 rear camber, with BSP Motorsports cranking them all the way when they aligned it back in May. We had already maxed out the eccentrics (see below right) and paint marked them - and they had not slipped with track use - yet - but it was a worry.



I can tell you definitely -2.3 / -1/78 deg setting with the stock eccentrics THIS IS NOT ENOUGH CAMBER and it was time to get a proper camber kit on this car to dial in more. And I know the internets like to argue for lower camber settings for every car, especially Corvettes with "superior suspension", but that's all just garbage. This is literally what I do for a living, and we test and race and look at long term tire wear and the data just shows it needs more.



There are memes we have to point out how ridiculous some folks' camber suggestions are - more than I have room to share here. Yes, even "double A-arm" cars need more than -2 deg of camber when you are tracking with tires making 1.3g - and these Yokohama A052s exceed that. When it comes to C5/C6 Corvettes, the method of getting more camber (what parts to use?) is where my knowledge ran a little thin - until now. Boy did we learn some lessons! We had done research but missed some of the options and skipped some others, and chose this LG Motorsports kit below.

LGM C5/C6 CAMBER "LOCK OUT" KIT

The tech around the LGM $369 kit was a little thin, but in June when I was there to have the C6 tuned they showed me how it works on a spare subframe they had on site and said it would "gain about another 1 deg of camber adjustment" which would seem ideal. It is billed as a "lock out" kit, to prevent the camber from slipping - and the mating sawtooth plates make sure of that. But the extra degree of travel just... isn't there.



This kit is built around part of another bolt-to-stud conversion kit from Vansteel and their own toothed adjusters, that allow for fixed amounts of change. The idea here is to not allow the stock eccentric washer to "slip" under high loads, esp. with a curb jump on track. That never effected our car, but we just couldn't get enough adjustment range - and I had hoped this kit would add more.



On July 5th we had the C6 in the air for this camber kit install (and the swaybar install) and I helped rummage around until we found the old set of "shims" we had on hand from another C4/C5/C6 alignment years earlier. I wasn't quick enough to spot the offset hole slugs in that "shim" bag, above right...



Brad got to work and swapped the bolts for the Vansteel studs, shown above. This makes it so the alignment shop can slide shims behind the upper arms to dial out some camber and/or to set caster. That went quickly and looked useful. Now it was time for the saw tooth "lock out" inserts to go in...



Brad got the first sawtooth plates installed with the bolts in the lower front arms - both of which had a slotted hole in the subframe and are adjustable for camber - and set them to the max outboard / negative camber position. The rear, strangely, only has one adjustable lower bushing - the front lower, as shown above.



But Brad quickly noticed that this LGM kit doesn't allow more camber adjustment than the stock eccentrics. The first image above shows the extreme "negative" camber travel allowed with their lockout kit inside the unmodified front cradle. The second image shows how much more travel the cradle slot has - its another .100" of movement that their kit cannot achieve.

THIS ONE GOES TO 11...

Now .100" of travel might not seem like a lot - but it is. It was worth almost a degree of additional camber travel up front and .7 deg more out back, once we had the car aligned. Read below to learn from our mistakes further.



The images above show how much travel the lock out kit is giving up - and the top right image is with the bolt pushed to the limit of the factory slot. I'm not saying that this is a "bad kit" because it only allows for the same camber extreme as the stock eccentrics, and it does stop any slipping - so it is a "Lock out" kit. It just doesn't add any more camber than stock, and that doesn't work for me. I wanted this car with max camber, and we'd make something if needed!



We had to push forward for an alignment appointment the next day, so made our own slugs for that slotted opening. Jason whipped up a simple CNC program and had our CNC crew cut some sluts from .500" thick aluminum plate we had on hand (from camber plates). The rough outlines were CNC machines and then cut out on the band saw - we quickly produced some fixed slugs with offset holes that maxed out the cradle slots. Brad took the rough cut pieces, prettied them up, tweaked each one for maximum camber, and installed them onto the six lower control arm bushing spots (4 of the front locations and the 2 rear).



Brad got all 6 slugs finished and fitted to each spot on the cradle and wrapped up the camber change, swaybar install, and it all looked great. The problem was... there is already a kit to do this exact thing. And we had it in our shop the whole time.



So if you want more camber than the lock-out kit can get you, the Puff Daddy 450-401009-A camber / shim kit for the C5/C6 is what you want. And the Vansteel stud kit. The Pfadt kit has offset slugs in various camber locations, so your alignment shop can dial in the camber/caster you want (its time consuming so plan on a slightly more expensive alignment). We had essentially copied their most offset slug, without knowing this kit existed - and was sitting on our bench with the shims in a bag. (facepalm) Oh well, we only lost about 2 hours making the custom slugs. Learn from our mistakes!

continued below

[Fair!]

continued from above

There is also a kit from AMT ($350) that is a more complete and better version of an eccentric adjuster - it comes with the six lower adjusters, new lower bolts, and an assortment of shims for the upper arms to use at the alignment shop. And it can get ALL of the camber.



And they sell an even nicer upper stud kit for $70, too. This AMT kit makes for TEN fixed levels of camber changes and cannot "slip" like the round OEM eccentrics. AMT says this DOES allow all of the slot room to be used on the C5/C6 cradle, too. Even easier - just buy this kit!



Brad installed the 19x10" wheels and Hankook street tires and I loaded up the C6 and took it to BSP the next morning. We could have driven it there but they need a few hours to do the install and the trip there is 1.5 hours round trip, so I didn't want to have someone follow me each time I went to drop it off or pick it up. We installed the "NB" graphics at this step also!

ANOTHER BSP ALIGNMENT



BSP needed about 3 hours to dial in the upper shims, and I had them bias everything to get as much camber as possible - caster be damned! Lots of RED numbers means it MUST be a good alignment.



The initial settings with our maxed out lower slugs was pretty impressive up front - -3.2 on the LF and -3.85 on the RF. But the rear was holding everything back with only -2.5 deg of camber. They sent me the screenshot above and asked me what to shoot for. I worked with Jason here and we asked them to dial back the front camber (adding shims to the upper arms) to better match the rear camber.



This was the final compromise, which yielded even -3.3 deg front and -2.4 rear camber. We have the front toe at zero and .28 deg total rear toe in. We'll see how this works, but I will be looking for ways to get more rear camber so we can dial in more front. This battle isn't over!



Still, this was closer to my "ideal" camber setting and what we had run on other Corvettes, so I had some hope we could find some lap time with this change.

NEW MOUNT FOR AIM SOLO - MORE RAM MOUNT PARTS!

I'm still struggling with what video camera to use, and finding a better spot to mount the AiM Solo DL lap timer / data logger. I've had both on suction cups for a while.



We have upgraded the suction cup mount for the AiM to a RAM 1" ball mount on the PanaVise dash bracket, and that worked well enough - but it wasn't perfect. We could put a RAM quick release 3-axis phone holder onto the 1" ball for street use, but then swapped it to the AiM SOLO mount for track use. Strangely enough I've needed the phone in the car on track more than a few times - sitting in paddock or stuck out on track during a red flag to talk with Amy. Putting the phone into the center console simply COOKS it - literally puts it in "overheat" mode within minutes.



Secondly, with a simple 6.7" RAM arm and 1" ball mount at both ends angles the AiM unit off axis, and you cannot rotate it enough in the two balls to get it to align perpendicular to the centerline of the car. Its nice that it points towards the driver from the PanaVise, but it makes for skewed lateral g load data. So I bought a bunch more RAM mount arms and ball mounts to see if I could fix both issues...



And.... this 2 headed hydra is the result. But with the weight of the AiM SOLO and the giant Apple 13 Max Pro XL BBQ phone and holder, its just too much weight for a 1" ball on the PanaVise bracket, and it flops around and is unusable. It was a neat idea but it just didn't pan out. I was hoping to slip the Sony HDR-MV1 camera on a third arm from this junction, but it isn't going to happen. So I will contemplate cutting holes in the silver plastic dash surround to mount two more RAM ball mounts, maybe in the future.



At track test #11 (above left) I figured out pretty quickly that the multi-headed hydra was not going to work with the phone + AiM, but I still managed to get a "twisted" two piece RAM arm setup to hold the AiM solo "perpendicular" with the chassis centerline. And now the left/right lateral loads finally equal each other. I used that setup again at the July SCCA TT (above right) and that will be the AiM mount for now.

I will keep using the lackluster dual 1080P Road Keeper camera suction cup mounted to the windshield until I find a way to mount the Sony camera near the windshield (without a suction cup) or find a better narrow angle, vibration resistant, remote mic equipped camera to mount to the harness bar behind me.

BUILDING A SIM RIG TO LEARN ECR 2.7 CW!

I felt so lost at the June SCCA TT event at ECR for a number of reasons. I haven't driven at ECR since 2015, on the old 2.5 mile CCW configuration - but from 2008-15 it was my home track and I was there at least once a month. I set several NASA TT class records on the 2.5 but never drove it Clockwise. The extra 5 turns and new configuration for the 2.7 mile track, plus running it backwards, really put me on my back foot.



The next SCCA TT event was scheduled to be 4 weeks after the June event but using the exact same 2.7 CW configuration, and I didn't have time with our build schedule to get the C6 out there - and couldn't find another event that was running the CW config in that time frame, either. So I started asking some Sim Racing buddies for suggestions, ordered a really crappy frame on eBay (don't get this one!), then went to Micro Center, and spent a bunch of money...



When I found out that some local programmers at #HashtagRacecar worked with the management at ECR and got their GPS scan of the entire track, down to every curb, building, wall and shrub. They created the 2.7 CW and 2.7 CCW tracks for a game called Assetto Corsa, which is on Steam for like $20. I bought a nice PC with a big video card, three 32" curved monitors (2K), and tried two free steering wheels and pedals (thanks Facebook friends).



The free steering wheels and pedals were all too old so I went back to MicroCenter, bought a Thrustmaster force feedback wheel (TS-XW) and pedal set, a Thrusmaster remote gated shifter, Tony Kannan mouse pad, a good seat of headphones, and a badass TK triple monitor stand. This stand is a HOSS and made a world of difference - and the triple 32" curved monitors are the best part of this rig. I'm into this rig now for "more than I like to admit" but it's looking GOOD.



There are all sorts of tricks to load custom tracks and cars through a 3rd party program called Content Manager, but with some tech help I got the track loaded and a base C6 car installed (it was terrible). After many hours fiddling with Content Manager, some remote support, I finally got the game to work. Got the beta ECR maps loaded, fired up the 2.7 CW course, and started driving with various original content and modded / aftermarket cars.



I eventually gave up on finding a car similar to our T2 classed C6 and just drove dozens of laps with a GT3 prepped BMW Z4 using the flappy paddle shifters on this wheel, and not the remote shifter and clutch that I had purchased (there were more tweaks needed to the settings to make those work correctly - and apparently the pedals I have are "total junk" according to the sim snobs!) Just getting dozens of sighting laps helped, as you will see in my July SCCA TT write-up below. Going three seconds faster there after these sim laps was no accident! My wife Amy got in some laps (above left) and now my friends are bugging me to come by and make laps (above right) - and a friend on the #HashtagRacecar discord channel made a custom modded C6 that is pretty close to our car, too! I need to work on my ECR 2.7 CCW course now...

C6 TRACK TEST #11, MSR-C, JULY 14, 2022 (BUST!)

I took the 2006 Corvette to MSR Cresson on July 14th, 2022 to test out the latest round of updates - namely the alignment with -3.3 deg front and -2.4 deg rear camber, plus added swaybars from LG Motorsport. I got out there super early and was once again the only car on track in the 7:30 am session. Sadly I was the first car on track since some track repairs on Tuesday...



Unbeknownst to me the track management had dug up and laid down a big patch of asphalt in "Rattlesnake", a series of esses after the Start/Finish. To allow this patch to "cure" they covered this patch in a generous cover of lime dust (this spot has been patched before but kept coming apart). This patch was done Tuesday and I was the first car to drive on the track on Thursday, so it was fresh and powdery. The lime dust was like talcum powder - super slippery, and it took several turns to clear from the tires. It would take days to clear the dust off the track, without any rain or other action by track workers.



I went out and took 8 laps to try to eek out a little time from last test - I wanted that 1:20.X lap badly but it was not happening on this day with a major compromise to grip. Took another 4 laps in the next session - nope, it was all junk. I worried that maybe these tires had "gone off" but 3 days later we won our class at an SCCA Time Trial - so it wasn't the tires, it was the track issues, Test #11 was a bust.

SCCA TT @ ECR 2.7 CW - JULY 16 , 2022

This was to be our SECOND ever Time Trial competition in this narrow body C6, and at the same track as a month earlier! Fearing that the tires had fallen off a cliff (due to the slow times from Track test #11) I was more than a little nervous going to the second SCCA Time Trial at ECR on the 2.7 CW course.



I had driven many laps on the ECR 2.7 CW simulator in faster sim cars, but would that translate to more lap time here? We had also made the alignment and swaybar change - but had not verified that on track at MSR Cresson yet, so who knows if that would help.



This time Amy and I arrived right at 7 am, quickly unloaded the car at the lower paddock (where trailers have to be parked), and rushed the car up to the upper paddock before all the good spots were taken.



There is a section up top under a huge mesh fabric shade, and I snagged a spot to setup our paddock. We got too much sun at the June event and being down at the lower paddock we were out in the heat more than I needed to be - now we'd be staged closer to the air conditioned clubhouse and could hang out inside most of the time between sessions, or else in the shade in our paddock spot. This is as close to perfect as you can hope for on a July summer day in Texas.



I thought I got to the session 1 grid early enough to get a good grid spot (first come / first serve in session 1), but as am still "the new guy" a bunch of people leap-frogged me at grid once again and I started the session in P10. Several cars that ran slower than our C6 last time were ahead so I figured I would be mired in traffic again - and I was. Fought with a few cars for 3 laps and finally got a 2:09.143, which moved me up the grid to P6 - not great, not terrible. At least the folks ahead of me weren't that much slower, but I knew I had several seconds left in the C6...



The above video shows my best lap in the second TT session. You can see that I held back from Stan's new 2022 GT500 on the out lap by a solid 1/4 mile, building a huge gap that I would then use to put in a 2:06 lap, which ended up being my fastest of the day and 2nd fastest of the entire event. I caught him at the end of lap 2, but my first lap was quickest. Which is sad as that first lap was riddled with mistakes. Lap 2 was much cleaner from a driving perspective, but at 84F ambient and with track temps over 100F, the tires were slowing down considerably (2:07.3) in every lap.



We stuck around after lunch to try another lap in session 3, when ambient temps were up to 92F. Again, drove better and got it done on Lap 1, but it slowed down further to a 2:07.9. It was only getting hotter so we packed up, loaded the car, and were out of there by 2:30 pm. Fairly confident that we had secured 1st place in T2 again, we skipped the 4th session but watched live timing - nobody up front got any quicker in the higher heat of the 4th sessions.



I was pretty happy once I saw the results and realized the only quicker car was a C7 ZR1 with AP brakes, good tires, and a member of ECR who is always fast (he was quickest at the June TT event here, too). After a 3 year hiatus I was finally getting better at Time Trial competition again, and couldn't wait to dig into the rule book and see what else we could do to our narrow body C6. The 279F oil temps were concerning, as was my own body temp in a 3 layer fire suit.

Since that event the C6 was largely unchanged, with only new swaybars and more negative camber, it all came down to the sim racing rig time. With the help of #HashtagRacecar map developer Justin, I was able to drive this track in Assetto Corsa for hours and finally learned the layout. I still have 1-2 seconds of time left just in "driving", but at least I wasn't fumbling around in the 2:09s like in June.



I still need to work on my "first session gridding" technique, as this has hurt me two events in a row. I don't wanna be "that guy" that claims he drives FLAT OUT and needs to be at the front... but it is becoming obvious that our little LS2 C6 is ending up at or very near the top of the time sheets.



If you haven't driven at Eagles Canyon Raceway it belies the typical "Texas tracks are all flat!" stereotype with a lot of elevation change, hence the "Canyon name. Really fun track to drive, once you learn where you are going. I am still learning!



I had a bit of a "moment" in session 1, using a little too much of the inside curbing in Turn 1, based on advice from the track manager. Amy snapped a few pics of the "driftoro" moment there, which was 100% my fault - but it still deserved a meme. Managed to catch that drift and not damage anything other than my pride. Amy was a big help all day, keeping me hydrated, shooting pics, and helping load / unload the trailer. Someday soon SHE will be piloting this in TT and I will be in another car, but not today.

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[Fair!]

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COOL SUIT COOLER MOUNTED + WIRED

We started this install before the July SCCA Time Trial event above, but a borrowed cooler's pump was dead so we had to punt for that event (GROAN). Coolshirt.com makes 3 sizes of coolers with internal pumps: 13 quart, 19 quart and 23 quart. The middle size is the most popular and what we built around. The smaller one fits tight confines and the bigger one is more suited to longer stints like endurance racing.



I had our crew make a mounting tray to show off our fab skillz - don't do this! Just buy the damn tray from the cooler supplier. We wasted several hours making this to save ounces. Anyway, this shows the steps we did to make the mounting tray, which is taller on the front side than the typical ones. I marked the outline for what I wanted on the cooler in tape and Doug began making the tray mock-up in kraft paper.



With the template completed it was transferred to CAD, then that was input into our CNC plasma table the we cut out the shape from a .080" thick piece of aluminum sheet, including the slots. Then it was marked and hole sawed for dimple dies then those were pressed in. Now it went into the box and pan brake and 3 of the sides were bent up at 90 degrees. The final side needs to be done on the fab table with a slightly custom backer plate to make that last bend.



The finished box was now bent to shape, then TIG welded along the edges and the final weight was... 2.1 lbs!



Then we looked at the Coolshirt 19 qt mount and it was only 2.6 lbs. Really regret not just buying this ahead of time, ugh. Well we got it mounted ans strapped in and realized the pump was dead on the loaner cooler. So we ordered a new one.



The wiring for the pump needs to be on a 5 amp circuit, which is pretty low. We used DW plugs to make connectors for everything on the lower console "ash tray door" which is now our control panel for the seat heater switch, USB connector, volt meter, and the new suit cooler pump switch. We opted for the simpler on/off switch rather than the speed controller panel you can buy from Coolshirt for $250 (but after using this, I now see why that is used so often!)



Jump ahead past the SCCA TT at ECR and the new cooler and hose kit arrived, the mounting tray was painted red, and the cooler was attached with the little Velcro straps. This is a slick setup and I will be using this in multiple cars in the future!

BIG ROUND OF UPDATES!

After two TT event in a row, and none of our other "real" race car builds even on the schedule for work, it was time to "come into the pits!" and "finish" the C6 work, by fixing last lingering issues I noticed noticed. We had exactly four weeks until the next SCCA Time Trial, which was to be at my home track of Motorsports Ranch Cresson on the 1.7 mile CCW course I have driven on for twenty years. I wanted the C6 to be both fast and reliable there.



The rest of what we are allowed to do in SCCA Time Trial Tuner 2 class didn't amount to much, so we did almost everything in this round. We tackled several fluid temperature issues with coolers, fixed many fluid leaks that were bugging me, and added a tiny bit of power (and slowed down the power steering pump!) with an aftermarket SFI rated balancer, which is 10% under driven.



It takes a bit of work to add these additional coolers and meet the Tuner class rules, and those same rules restricted the oil / air separator also. All of this work below was done in the 4 weeks between the SCCA July (ECR 2.7 CW) and August (MSR 1.7 CCW) Time Trial events. Let's dive into each sub-section!

POWER STEERING FLUID COOLER + PUMP + RESERVOIR

The hydraulic power steering on this C6 straight out of the 1980s. It has a small reservoir, a tiny cooler (if at all), and starts to overheat quickly - that heat froths the fluid, which saturates the rag we wrap around the cap before each event. The howling pump and constant leaks - a leak AT the pump, one at the Z06 cooler (we had already upgraded to last year) and another at the reservoir - made for the trifecta of leaks!



I had this novel idea of placing a large high efficiency "plate and fin" cooler under the car - stuck up in the long and skinny spot that the transverse spring used to occupy. This would, in my opinion, get plenty of airflow from under the car without adding to the heat load of stacked heat exchangers up front (radiator + air con condenser + soon to be added engine oil cooler).



We picked this extremely wide 26" x 4" unit from Setrab, as that fit the strange confines of our transverse leaf spring pocket in the front undertray. We ordered some vibration isolators and Doug built aluminum brackets to fit the cooler and existing subframe holes.



These brackets mount the bottom of the Setrab cooler flush with the bottom of the car, with the isolators keeping vibrations down at the cooler. The power steering lines were built from Fragola -8 sized (1/2 inch) braided lines (these are all relatively low pressure). The high pressure line is still the stock metal hard line from the pump to the rack, so the pressure worries of changing to a soft line is not there.



We had debated and researched going to a TurnOne or other aftermarket pump, as the 16 year old OEM power steering pump was leaking at the front seal. We found out that the TurnOne goes to a higher pressure than stock, which we definitely don't need, so we bought a new OEM replacement. The stock pulley is re-used and that all went on without issue.



We thought that was all of the leaks - not so! The reservoir also had a hairline crack at the molded in seam, shown above left. That replacement was overnighted when it was shown to be leaking, and the new one went on with a fresh rag around the cap. Hoping for 100% leak free at the next TT event!

THERMOSTATIC TAKE-OFF, OIL COOLER + PLUMBING

Engine oil temperatures were getting somewhat alarming, with 280-290 deg F and higher temps. This was with rock solid 205-210F coolant temps behind our DeWitt aluminum radiator but NO factory oil cooler in many previous tests and the June + July TT events.



Another large Setrab (23.5" x 6") cooler was slated to be added for the engine oil cooling, and after looking at several positions the only viable choice was stacked in front of the radiator. Getting the oil out of the engine and back in - in a safe and controlled manner - was the trickiest part of this oil cooler install.



We started initially with this thermostatic bypass oil filer sandwich plate from Improved Racing. That looked like the best option - on paper - until we installed the 90 deg adapter ends for the -12 AN lines, and that hung down lower than the oil pan. Not safe, time for Plan B!



This improved Racing oil pan mounted thermostatic bypass unit is much lower profile and the lines come out and can hug the block, and we can keep the stock oil filter or even run a longer one without ground clearance issues.



Another set of brackets were fabricated by Doug to mount the Setrab in line and in front of the DeWitt, with isolators used at all four mounting points one again. Only slight trimming of the factory radiator shroud plastics was needed, but this will add more heat load to the AC condenser and radiator behind. Due to class rules for SCCA TT Tuning 2 class we could not cut holes in the body to keep from stacking the coolers, and the itty bitty coolers I've seen people try to run behind a fog light hole just aren't going to do it.



Giant -12 AN sized Fragola braided lines were built to run to and from the oil bypass, which only opens after the oil gets above 185F. We filled the system with Motul 5W50 ester synthetic oil, and the cooler added about a 1/2 liter of capacity.

ATI 10% UNDERDRIVEN BALANCER + OIL PAN LEAK FIX

One of my pet peeves is leaks - and the oil pan has been leaking since we bought this car in Spring 2021. Just a drip here, a drip there, but still. With all of the work we had planned I asked Doug to drop the subframe to get the oil pan out. I then took the pan to HPR and ran it through two 15 minute cycles in the sonic cleaner and got it looking like new. There is no baffle kit for this oil pan so we are leaving the pan alone, which went back in with a new GM oil pan gasket, leak fixed.



Another thing that worried me was the 16 year old stock balancer. I've seen bad things happen with old rubber isolators falling out or slipping and wiping out bearings in an engine. The SCCA TT Tuner rules allow for all different pulleys (except supercharged cars) and ATI made 3 sizes: stock, 10% under driven and 25% underdriven. For a pure race setup the 25% unit would likely be the best but that would compromised things like the alternator, power steering and AC use at idle. And I damn sure use the AC in this car at idle speeds, in the grid!



After talking with the folks at HPR and our crew I picked the 10% underdriven unit, which should unlock a little power and slow down the power steering pump (which can only help). I ordered the ATI917278 with a 4 rib AC pulley, made for the C6 pulley arrangement. Well...



The inner hub is supposed to press onto the crank snout with a .002" press fit (meaning: it should be about .002" smaller ID than the crank's OD). Problem was there was an .008" difference. So Doug chucked it up in the engine lathe, cut it to the exact size we needed, and pulled it on with the ATI balancer installer then secured it with a new ARP bolt.



Last thing I will mention here might save somebody some time. The ATI catalog lists all of their LS balancers, with part breakdowns for the shell, hub, and even has notes for what belts to use. But the AC belt they recommend to work is wrong - what we used was 1.5" shorter (4040395) - and the part numbers for serpentine belts is "smart" - the "395" equates to 39.5", and the "4" at the front is for 4 ribs.

OIL/AIR SEPARATOR & PLUMBING

The last piece of this round of updates has to do with adding an air / oil separator. We had noticed after the last TT event that there was engine oil DRIPPING from the cold air, and it covering the bottom of the front of the C6. Oil was also pouring out of the intake due to excessive crank case pressure / high engine revs - I had to actually clean up an oil spill in our paddock spot at the July TT event from this!



In normal use the PCV (positive crankcase valve) system opens a check valve attached to a valve cover when up under engine vacuum, that then allows crankcase pressure to travel via vacuum through a hose that dumps into the air intake tube, and is then burned as part of combustion. That crankcase pressure is both exhaust gases and unburnt fuel that gets past the piston rings, as well as some oil vapor and even water vapor. BUT at higher RPM the crankcase pressure can get a little high and it carries some liquid oil with it (especially the frothy foam that can happen with an LS engine on track) and you get liquid oil pouring into the intake, which causes detonation and in this case, oil dripping out of the aftermarket cold air kit.



It was so bad we actually pulled the stock LS2 intake manifold and cleaned it and the throttle body out, cleaned out the cold air tube, and also cleaned the front radiator shroud. It was time to act, but we have to keep the emissions system "street legal" for SCCA TT Tuner class, which means the PCV must still function, so we cannot just add a crank case breather / catch can like we do to most race cars...



For street cars a sealed catch can plumbed in-line with the PCV system is what you want. Above is from my 2011 Mustang GT, which we raced in NASA TT3 class for years but always kept it street legal (for various reasons - not because that class mandated it). We install a JLT oil separator on the car early on, but these came with cheap plastic fittings and hoses that tended to crack or leak, so we re-engineered the whole system with new hoses, hardware, and an actual mounting bracket - not relying on the hoses to hold it. We had to drain this after each event, as it would catch some oil.



On a race car, like the ST2 classed Mustang above, we tend to go right for a Peterson vented oil catch can. This just has a feed hose (or two) from the valve cover(s) that allows excess crankcase pressure to go into this can, then the oil is "trapped" by the open cell foam filter media inside. The excess vapors then exit via the vented top, and you can drain the oil out after events (like this).



But for Tuner class, we need a SEALED system that relies on a functional PCV system, as we now have (see above). This is where you keep the PCV (positive crankcase valve) system intact - which opens when up under engine vacuum, then crankcase pressure can escape, and instead of dumping right into the intake tube it travels through a "filter" inside the air / oil separator... then onto the air inlet tube and can be burned via combustion. This keeps stinky exhaust fumes or unburned fuel out of the atmosphere.



We bought this TFS sealed air/oil separator (above left) but it was made wrong - none of the mounting holes were tapped, and the plumbing looked a little sketch. The only other sealed system we found was this one from Lingenfelter. Their plumbing also looked a bit janky, then Jason recognized the actual tank / filter they were using.



He found this same exact tank / filter unit online for about $45 and we rounded up some better plumbing bits (without any brass fittings, yuck!) and then I picked a location in the engine bay for it. Then Doug built this bracket to hold it off of the factory battery tray. Yes there are dimple dies!



The engine bay is getting a bit tight so this spot allows for it to be mounted high and out of the way. Jason spec'd and ordered some black Fragola fittings that Doug then epoxied into the large openings for the crankcase inlet and outlet.



We ordered some HPS 5/8" diameter heavy duty silicone hose to use for the catch can plumbing - we have had sealed systems that had enough vacuum to collapse weaker hoses. One hose went to the valve cover (PCV) and the other to the cold air intake tube. A third line went from the BOTTOM (drain) of the catch can down through another hose to the 1/2" stainless steel ball valve, shown above right.

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