Vorshlag Motorsports Forum

Vorshlag Motorsports Forum (http://www.vorshlag.com/forums/index.php)
-   Vorshlag Project Cars (http://www.vorshlag.com/forums/forumdisplay.php?f=39)
-   -   Vorshlag Budget TT Build: Project DANGER ZONE (http://www.vorshlag.com/forums/showthread.php?t=8341)

Fair! 01-16-2015 11:55 AM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued from above

http://vorshlag.smugmug.com/Projects...DSC_5574-S.jpg http://vorshlag.smugmug.com/Projects...B61G3586-S.jpg

The factory seat mounts are reinforced with extra steel from the factory, but we added more. 1/8" thick steel plate wraps around the stock stuff and was stitch welded to the floor as well as wrapped around up into the tunnel and frame on the sides, where it is bolted or welded for more support. The harness anchors for the lap and anti-sub belts are from G-force. These eyelets allow the clip-in ends from a Cobra/Schroth 6-point Profi-2 harness to attach. These are my favorite harnesses and made by Schorth in Germany to FIA specs. This set has 2" upper shoulder straps to better work with he NecksGen HANS device I will be wearing this weekend.


As usual, any "pretty" pictures you see here were shot by shop manager Brad with his Canon gear. The rest of the pics are from my "potato-cam" Galaxy S4 camera phone or my Nikon D90, which I can't seem to use worth a damn. The shoulder harnesses were wrapped around the harness bar tube with the proper wrap technique as specified in the diagram on page 42 of the NASA CCR.

http://vorshlag.smugmug.com/Projects...DSC_3510-S.jpg http://vorshlag.smugmug.com/Projects...B61G3603-S.jpg

Last but not least, a 2.5 pound fire extinguisher was added. This is a small "Halotron" (Halon replacement) hand held fire bottle that can be used to put out small electrical, oil or grass fires and doesn't leave a big mess of dry chemical or foam residue behind. We add these things to every track build possible, even when they have a full fire "system" with multiple nozzles. No need to blow a big bottle when all you have is a little grass fire under the car after pulling off track into dry grass. We used the Drake quick release mount here, which we have used a half dozen times. CNC aluminum, roll bar or floor mounting with the same kit, and one pin can be pulled for fast bottle removal but it stays tight and rattle free when racing. Good stuff.

Weight Check!

Now you've seen how crazy I am about dropping weight and weighing everything in this and other build threads. Weight is the enemy! Lowering weight helps all acceleration vectors, be it braking, forward acceleration or lateral acceleration (cornering). We do a LOT to lower the weight on any race car build, and this car has gone from about 3300 pounds stock (we never weighed this car with the interior but that's what my 1994 Corvette weighed) down to about 2720 pounds. This weight drop was from lighter wheels, no interior, no passenger seat no side or rear glass, and no HVAC bits. The air conditioning compressor has been removed as have the headlights. The lighter wheels and tires help, too.

http://vorshlag.smugmug.com/Projects..._ballast-S.jpg http://vorshlag.smugmug.com/Projects...t_driver-S.jpg
Left: 2841 pounds with fuel but no driver or ballast. Right: 3200 with driver, fuel and ballast

We have added about 60 pounds in the roll bar and about 120 pounds of fuel (its nearly full) and the heavier J55 brakes and it was sitting at 2841 pounds. That's a solid 700 pounds lighter than our TT3 Mustang was without ballast or driver! Sadly we have to weigh 3203 pounds with driver (or else we have to burn points to run lighter), so ballast went back in in the above right picture to get us there. The plexiglass hatch should help remove about 30-35 pounds out of the 46 pound OEM glass, but it might not arrive in time, so we will save that 3rd 45 pound plate for then.

Classing Sheets, Dyno Test and Custom Tune

So we haven't built "letter" class car for NASA TT or PT before, but have helped a number of people class their cars. The base classing + mod points thing is nothing new to us. Just like TT# (numbered) classes, the TTx (letter) classes have an adjusted power to weight ratio. In TT3 the class has a 9:1 ratio but we were able to get ours to 8.8:1 with the adjustments. Likewise, TTC's base 12:0 pounds per horsepower limit has some adjustments as well, namely with a smaller tire...


Using the 245mm tire has had so many benefits and this is just one more - we get a 0.8 ratio bump for this small tire. That might not seem like a lot, but when you are at 3203 pounds it is nearly 20 extra horsepower allowed...
  • 3203 pounds / 12 = 266.9 whp (267 rounded up, in favor of the driver)
  • 3203/11.2 = 285.98 whp (286 rounded up, in favor of the driver)

Which is a good thing, as it was going to be hard to only make 267 whp even with a dead stock engine, manifolds, cats and muffler. We had the car over at True Street Motorsports yesterday and they were able to coax 284 whp and 331 wtq out of this 24 year old, bone stock iron block LT1, through the stock cats, manifolds and exhaust. Not too shabby. It even sounds better after the tune.

Above: Video of the stock LT1 motor at idle and revving, after the dyno test.

We have our dyno plot and classing sheet attached below. As you can see we've started with TTC + 7 penalty points, which left us with 12 points to play with. We got one back for running 245mm tires (-10mm below base class tire) for 13 points total. We burned 10 on the Hoosier R7 and still have 3 points to play with. We will be very stingy how we spend those this season, so stay tuned to see what we invest these points in to make Danger Zone faster.

http://vorshlag.smugmug.com/Racing-E...%20Sheet-S.jpg http://vorshlag.smugmug.com/Projects...y%20Form-S.jpg
Left: The SAE corrected dyno plot making 284 whp. Right: TTC classing sheet with points

Last Minute Tweaks and Fluids

The Moroso oil pan for this motor is huge and the motor now holds 8.5 quarts of Mobil 1 synthetic oil (15W50 is my preferred weight for track cars), with a fresh Wix oil filter. Olof went over the car and filled out a NASA tech form but we still need to get a Logbook issued for the car at the event, so the plan is to leave Dallas early and make the 4.5 hour trek to south Houston on Firday and get there before dark. Then I can set-up the trailer, unhook, unload the C4, get the logbook tech and weighing, and make sure we have our ballast set correctly.

http://vorshlag.smugmug.com/Projects...DSC_5585-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5589-S.jpg

I couldn't leave the massive openings in the hood where the pop-up headlights used to be so I asked Olof to make some aluminum brackets to bolt to the inner hood structure and to the existing holes in the headlight covers. Those went on and now forms a fairly seamless clamshell hood surface. The front turn signal and corner light assemblies were also reinstalled to fill holes. We will go back and make flush mounted aluminum covers later, when we have the time.

http://vorshlag.smugmug.com/Projects...DSC_5586-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5592-S.jpg

Brad jumped into the Danger Zone this week as well and did a lot of wiring and some light fab work to the Corvette. He used to race a C4 himself and knows the car all too well. The wired AMB transponder from our TT3 car was moved to the C4 and Brad made some brackets for that, wired it up to a lighted switch (sometimes its handy to turn off the transponder - if we want to make another entry in the same car with the 2nd battery powered transponder we have). He also got the rear brake lights to work, after repairing some cut wires.


He made an aluminum panel to mount the switch in the center dash area as well as the 3-port "power panel" shown above. This was a cheap Amazon.com purchase which arrived in only a few days for $31 shipped. This panel has waterproof covers over a 12 Volt cigarette lighter port, a volt meter and a stack with dual 5 Volt USB ports (one a high amp and the other a low amp draw - see detail image above). Very slick little package that should prove handy when it powers my onboard vidcam and AiM SOLO timer. I will report back with how well this worked, or not.

http://vorshlag.smugmug.com/Projects...DSC_5594-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5599-S.jpg

The formed, lightweight, plexiglass rear hatch we ordered a week and a half ago arrived this morning so there's no time to fit it, so we reinstalled the OEM back glass. Order Desk Manager Jon wrapped the "ugly" mis-matched door with white vinyl. He also designed, cut and mounted graphics for our logos, "DANGER ZONE", Hoosier and Bilstein decals, and some class/number decals for all sides of the car.

http://vorshlag.smugmug.com/Projects...DSC_5596-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5597-S.jpg

Its time to load up so I didn't get the final pics... tune in next week for the post race update to see the final look, or look for it on Facebook with this hashtag #DANGERZONE.

What's Next?

The only thing on my RADAR right now, outside of cutting metal next week on our new CNC machines (tooling is FINALLY here!), is the race this weekend at MSR Houston. I will be paddocked with Costas, Matt White and other friends probably near Turns 16-17.

http://vorshlag.smugmug.com/Racing-E...IMG_2369-S.jpg http://vorshlag.smugmug.com/Racing-E...n%202013-S.jpg

We are running MSR-H in the Clockwise direction this time (they alternate the direction for NASA events every other year), so I haven't run this track layout since 2013. The video above shows the lap record I managed in the TT3 car 2 years ago, on the skinny 315 tires. The lap record for TTC is currently a 1:50 but I think we might be able to manage a 1:46 if everything manages to stay together on the car...


We have a pretty crazy class lined up: Our 92 Corvette, a 2003 Mini Cooper S (fully race prepped) and a 2005 Mazda RX8 (fully race prepped). Talk about an odd mix... and we will once again be the heaviest yet most powerful car in class, just like we were in TT3. I will post up more details after this weekends race. Until then...


Fair! 01-26-2015 11:34 AM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
Project Update for January 26th, 2015: Our first race for Project DangerZone has passed and this is my "post-race report" along with some analysis of what went right and wrong.

I Need To Apologize for Trash Talking? Really?

Before I get into our first event results or talk about what we're doing to this car next I think I need to address some of my "pre-race performance speculation", aka: TRASH TALKING. Some say it was unnecessary or disrespectful, but it was done mostly in jest. Getting people to notice our projects takes some extra effort when its a 24 year old ghetto jet, so I took a gamble and "bench raced" my way to some predicted wins and track records. Where's the harm in that?

This was how the car looked right before we loaded up to tow to Houston, sans NASA decals

This sport isn't an "everyone gets a trophy" kind of competition. There are winners and there are losers - that's kind of the whole point. Sure, racing is still fun when you lose, but winning is more funner. Since when do racers need to apologize for a little harmless trash talking? To those that were offended by any of that in my previous posts, all I have to say is "that's part of racing". If I chose to I talk up this project a bit and had it flopped the first time out, I would have looked like an idiot and had to eat some crow. That was the risk on my part, but this whole build is a calculated risk...

The Gamble: An Old Car And A New Tire

Building this 24 year old car into my primary race car for 2015 is a big risk, as it didn't really fit into the "typical cars we work on here". I've picked the wrong horse a few times but normally we can look at a rule book and class listings and see several underdogs that have unseen potential.


But honestly, this car isn't magic. We could have picked a number of other low cost cars that could do very well in this class (TTC), like an E36 M3 or an S2000, both of which are proven winners in TTC at the highest levels. The point of this build wasn't to find the End All Be All car, but to show that as long as the classing is equal the car you choose doesn't matter as much as how it is prepped and driven.

http://vorshlag.smugmug.com/Vorshlag...SC_0231a-S.jpg http://vorshlag.smugmug.com/Vorshlag...SC_0341b-S.jpg

Am I saying the class could be won with any of these cars? Yes, I am. This 1992 Corvette isn't some super ringer, and we've prepped/won with both S2000s and M3s in this very class, with our own cars and customers' builds. Anyone can win if they start with a fairly classed car, prep the car to the limits of the class, test their set-up to maximize performance, use the best tires available (*tires are the biggest factor in any build!) and drive it well.


Another reason why we chose this car (other than it was a sweet deal that fell into my lap at the perfect time) was to show some variety for our business here at Vorshlag. We have unfortunately become "known" for BMWs and Mustangs and Subarus, but the reality is we work on anything that can be classed for road course, autocross, rally or other racing uses: new and old, Domestic, Asian, and German, you name it. People didn't "know us" for Corvettes but we have owned, raced and worked on a lot of them, and use the drive trains from Corvettes in a number of V8 swaps for all sorts of chassis. Having owned this same model Corvette in the past I knew it has potential to handle, brake and accelerate well. To me this C4 was a fairly safe bet, but the fact that it was a 24 year old car made for the biggest gamble. Any number of "old-car" things could have failed at the first event and shut down the weekend before the car ever turned a lap.

http://vorshlag.smugmug.com/Projects...DSC_5575-S.jpg http://vorshlag.smugmug.com/Racing-E...8_120911-S.jpg
Left: The R7 tires were new when we got to the event. Right: After a race weekend with 5 sessions and 3 drivers - tires look great!

The tire was another unknown - the Hoosier R7 was relatively new and we had zero experience with it (I ran the 2013-14 seasons on the A6 in much larger sizes). We also chose to go with a narrow tire width (since there weren't many R7 sizes to choose from yet, as more sizes are being rolled out as the R6 sells out of inventory). Would a 3200 pound car be able to survive on a 245mm tire? It was another gamble. If the tire didn't hold up, we would have to revisit our choices.

http://vorshlag.smugmug.com/Racing-E...DSC_2543-S.jpg http://vorshlag.smugmug.com/Racing-E...6_094849-S.jpg

Some folks sent me links to this build thread discussed online and apparently a few racers were upset that a "big money shop" was coming into the "grassroots" TT letter classes and bringing a purpose built race car against their TT cars they drive to the track. To them I say: the NASA TT rules don't have any wording about this set of classes being for daily driven cars, and in fact the TT division shares the same rules as NASA Performance Tuning - which is for wheel to wheel racing cars - just without the safety regs. We already see PT cars running in TT all the time, because the contingency is good and the PTB-PTF classes are direct crossovers to the TTB-TTF classes. The same holds true for TTU/1/2/3 and SU/ST1/2/3. Time Trial is a haven for race cars but also allows cars without full safety gear to enter.

http://vorshlag.smugmug.com/Projects...DSC_5367-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5362-S.jpg

As for this being a "big money build", that is hilarious and absolutely not what we have done here. This was a last minute option, "Plan B", eight day long race car build - that isn't finished. We had no other car ready for 2015 season, this deal fell into my lap, from a friend who I had brain stormed this car build with three years earlier, and I took this gamble - to have something to race. We have about $5000 dollars in parts/car purchase and about 60 hours of shop work (we log all jobs to the 1/100th of an hour) in this build so far. We worked on this car between regular customer jobs and only spent 8 days actually working on it, but it held together for the first race weekend (barely). We spent our time almost completely on the safety aspects the car needed and left everything else stock for this first event.

If the "speculative talk" in my first few posts here have people fired up to come join us in TTC - that's good! I'm hoping people look at how little money this car costs to buy and prep, how it has proven itself already, and "get the bug" to build a car for NASA Time Trial letter classes or Performance Tuning! This set of classes allows a lot of freedom to choose what you want want to concentrate on: suspension, tires, horsepower, aero. The rules are structured to limit your overall mods which in turn does limit your spending. Its a great series and I encourage people to look at the TT rules/PT rulesets, check out the car "base classing", and start hitting CraigsList looking for something fun to start with. It doesn't need to be a brand new car or an expensive car - look at the past and see how some of the best cars from the last 2-3 decades are classed.

As you may remember, I had proclaimed we could win TTC with this car its first time out, reset the lap record, and even predicted some bold lap times for our first event at MSR-H (1:46 clockwise). So, how did it all play out at our first NASA race weekend? Do I look like a stooge talking out of my hat, or was our guess work correct and did we prep the car in the limited time available in the right areas?

NASA at MSR-Houston, Jan 17-18th, 2015 - The Debut Event!

The old TTC lap record was a 1:50 here was set in 2013, which I showed in my last post on the Friday before the race. I had predicted a lap time of 1:46 but had privately hoped for a 1:45 lap. Let's back up to where I left off in my last post and get caught up on this debut weekend of racing for Project #DANGERZONE.

Friday January 16th, 2015 - Unloading and Tech

After Jon finished installing the decals and I fired off my pre-race forum post, we loaded the trailer and I left Dallas a little late, at about 12 noon - wanted to leave at 10 am. Took me a little over 5 hours to tow 300 miles to the south end of Houston, where MSR-H is located. Google maps has gotten better of late and it re-routed me around 3 construction zones or crashes, on a goofy route, but I never had to stop. It would re-route me on the fly, ask me to verify, then I'd go... which was nice. I got to the track at about 5:30 pm, at dusk, and Costas had a paddock area set-up with his trailer plus both of Matt's trailers. It was pretty far from grid so we did a lot of walking back and forth all weekend. We squeezed my trailer in near Turn 17 and I unloaded the Corvette and rushed to tech as the sun dropped.

http://vorshlag.smugmug.com/Racing-E...6_172019-S.jpg http://vorshlag.smugmug.com/Racing-E...7_110923-S.jpg

The tech guys got me in fairly quickly, right as it was getting dark, and they went over the car with a fine toothed comb. The only thing they could find were the side post battery terminals were uncovered... now normally I'd agree that a top post battery ALWAYS needs plastic around the terminals in case something gets dropped on them, but these were buried on the side and covered by the fiberglass body. Some duct tape and I was legal for this event. I will add the rubber terminal covers soon.

http://vorshlag.smugmug.com/Racing-E...7_161030-S.jpg http://vorshlag.smugmug.com/Racing-E...8_122640-S.jpg

Any time you have a new car teched for NASA Club Racing classes or NASA Time Trial for the first time you have to get a NASA Log Book and a NASA annual tech sticker. The log book cost me $20 and the annual tech decal cost me $10. From here on it would only need the annual $10 decal, as the Log book is good for the life of the car. We're working with NASA to be able to issue log books here at Vorshlag, which should happen soon.

They didn't have the scales set-up Friday night, due to a mix-up with the ramps, so I left the ballast in the car a bit on the heavy side (about 25 pounds over by my calculation) and figured I would weigh the car in the morning before we went out on track. Nobody likes to get a surprise weighing and end up underweight, so I ALWAYS try to weigh the car at the track on Friday or Saturday to make sure our scale numbers match up with their scales.

Reloaded the car back in the trailer, said hi to everyone hanging out, and shared half of a pizza, which I scarfed down on my way to Matteucci's at 7 pm. Crashed out at his place and dreamed of this track layout all night...

Saturday January 17th, 2015 - Race Day 1

I hastily made the TT map (below) for Motorsports Ranch Houston (MSR-H) right before leaving town Friday, which shows not only the track layout and direction we'd be running this weekend but also two special cues for the TT group. First is the "Bunch Up" line, which is between Turns T7 and T6. On the out lap in each session TT drivers can drive somewhat erratically to scrub tires and warm brakes from Pit Out to this line. When cars approach the Bunch Up line they need to quit screwing around and form a single file line with tight spacing. This is done to keep the field from getting spread out and hopefully prevent the front of the field from catching the tail.


The second line to note for the out lap is the "Go Green" line, where the leader of the pack should get up to speed, this time so the field isn't bunched up too tight going into the first braking zone. Starting to go green too LATE only keeps the field bunched up on the first hot lap, usually making that lap slower than it should be for everyone. The TT field should be gridded fastest to slowest, in that order, and this order changes all weekend if a driver goes faster (but not if they go slower).

We had our TT meeting at 8 am Saturday right before our first TT session, called "TT Warm Up" scheduled at 8:45 am Saturday morning. In the meeting we met all the new TT drivers, talked about safety aspects, and went over two areas that will be policed as "out of bounds" and counted as a 4 off if the driver is caught with 4 wheels past outside curbing in two spots that are paved beyond the track limits. Its a long story but there's a shortcut going CW at Turn 1 if you drive inside a curb and knock over the cones they have there to separate the Pit In lane. Another area is between T16 and T17. Each Race Director (RD) makes these decisions and declares out of bounds for each Race Group. Our RD for Time Trial is Richard Wootten.

http://vorshlag.smugmug.com/Racing-E...DSC_6127-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_5898-S.jpg

Saturday's "TT Warm Up" is a unique TT session for the entire weekend. We grid ourselves by guesswork (since nobody has any lap times yet) and then the times from this session are what are used to grid the field for the first "real" TT session, TT session 1. Times from the TT warm up do not count for competition, but gridding well is important. Lastly, Saturday counts as a separate competition from Sunday, and each day we have 3-5 sessions to get our best single lap time in. The goal is to have the best lap time in class, and a first place finish in a given day nets you 100 points for the regional championship. Hopefully you win your class with enough competitors entered to score contingencies. The only one I care about is tires: to win Hoosiers you need 5 in class per day to score 2 tires for 1st place. With 7 in class they will additionally pay 1 tire to 2nd place. That's assuming the 1st and 2nd place drivers are signed up ahead of time with the Hoosier contingency program, and run Hoosier tires and decals all weekend.

http://vorshlag.smugmug.com/Racing-E...7_091916-S.jpg http://vorshlag.smugmug.com/Projects...B61G3572-S.jpg
Left: The R7 looks good after the first session. Right: The hope is to buy the first set and win 4 more each weekend...?

I got to grid fairly early at Warm Up and slotted in about 8th in line, behind Alan Page's TTB prepped E46 M3. Alan is a customer we know from previous work we've done to his car and he's also fast, with several wins and track records to his name. He was shooting for the TTB track record, set 2 years prior by another E46 TTB racer KenO. A lot has changed in the last 2 years, both to the prep level of cars in NASA Texas as well as the track and that day's conditions. Two years ago was COLD yet all of the old MSR-Houston CW records were set that year. We felt like many TT records would fall at this event, especially the TTC record of 1:50.534.

Video of first laps ever in DANGERZONE - the Saturday TT Warm Up session

If you watch the video above you will see me learning to drive this car while taking it easy on a new set-up. Before that session I had never driven the car more than 100 feet. I guess I know MSR-H fairly well, having driven it maybe 5 previous weekends in the past 6-7 years, but its by no means an easy track. It is also run in both directions and the two courses are quite different, and I think I've done this config 2 or 3 times. The 2.38 mile course was run ClockWise this weekend.

http://vorshlag.smugmug.com/Racing-E...DSC_5966-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6208-S.jpg

So I went out in the Warm-up and tried to follow Allan's TTB E46 M3, who had been there testing on Friday and was dialed in. He was also wearing his fancy newly painted helmet livery! He was on a sticker set of 245mm Hoosier R7s so I figured our grip levels would be similar, but his power-to-weight ratio should exceed ours so he'd probably pull away from me - which he did. Luckily I gridded early and got ahead of most of the field, including the other three TTC cars.

continued below

Fair! 01-26-2015 12:17 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued from above

http://vorshlag.smugmug.com/Racing-E...DSC_6155-S.jpg http://vorshlag.smugmug.com/Racing-E...7_122842-S.jpg

The other TTC cars included BJ Mayer's 2003 Mini Cooper S, from Clown Shoe Motorsports, above. This was his beefed, up daily driven, TTC car's debut. It has a better power to weight ratio due to the 205mm tire he runs (>245mm tire = +0.8 ) as well as it being FWD (+1.0), for an unadjusted ratio of (12.0 - 0.8 - 1.0) of 10.2:1 pounds per whp. This car had GAZ coilovers, Vorshlag camber plates, a header/exhaust, supercharger and engine engine mods to help it make more power. I think his race weight was 2550 pounds or so? He told me but I forgot. He was on the SpecMiata tire, which is a 205mm "SM7" Hoosier (essentially an R7).

http://vorshlag.smugmug.com/Racing-E...DSC_6188-S.jpg http://vorshlag.smugmug.com/Racing-E...7_122701-S.jpg

The TTC regular for the Texas Region was Herberto Ferrer in his 2005 RX8. This car is pretty well prepped and he runs the Hankook R-compound race tire, but I am unsure of the rest of his mods. This is a dedicated race car, though, and he is at almost all of the NASA Texas events running TTC. We also had Bryan Leinart who brought his CMC 4th gen Camaro into TTC for two sessions (Warm up and TT session 1) on Saturday and Sunday.

The ugly side of the Corvette. We're working on it.

I took my first two laps pretty easy in the TT Warm-up and tried to follow Allan, as planned. I was still feeling out the car, shift points, brakes, and tires when I botched a downshift going from 5th to 4th into the Courusel, T2, on hot lap 2. Instead of grabbing 4th as I had hoped it went into 6th, but I didn't realize that for a few hundred yards. The motor made all sorts of grumbling noises and had ZERO power. I coasted for about 400 yards around the long 270° corner dubbed the Carousel (Turn 1) and even past the start finish line. I had seen a 1:49 on predictive timing flash by on that lap, but with the long period of coasting it made for only a 1:50.692 lap. I finally figured out what happened by T17, downshifted into 3rd and set-up for another hot lap. Then I caught the back of the field pretty quickly and started smelling some oil smoke, so I came in early.

What I had found when I went into 6th was what the engine tuner warned me about - there's a massive dead spot in the engine between 2000-2200 rpms. Nothing happens - it makes no power. This makes the car drive poorly at these low RPMs, as when you hit 2000 it wants to die. So I made a note to keep the revs above that range, even on the warm-up and cool down laps, and it didn't happen again all weekend. Kind of freaked me out when it happened, though. "Old car stuff"... probably a worn out sensor or something, but the 1992-only engine computer is really limited and hard to diagnose issues with.

http://vorshlag.smugmug.com/Racing-E...7_092551-M.jpg http://vorshlag.smugmug.com/Racing-E...7_092542-S.jpg

Once I came in I went back to my paddock spot and Matteucci and I looked at the smoking issue. Just as he had warned me it was the rear main seal leaking. He had already replaced the RMS once, so I figured it had to be something else. After power washing the bottom of the car to clean all the oil residue off, it never leaked another drop when idling at the shop... but after a few hot laps on track it was clearly a leaking RMS. After we let the car cool for 20 minutes with the hood up we moved the car to get it in the air, and the oil spot (see above) was the extent of the puddle. Not much, about the size of my hand, but every drop that leaks out while driving on course hits the exhaust 4 inches away and made for a SMOKE screen. Luckily this only started after two hot laps.

Times from TT Warm-up - I was in 4th out of 4 in TTC!

I thought we would be sitting up front of the class, even with the 1:50 time, but that was wrong - I was in LAST PLACE out of 4, ouch! I quickly got some text messages from people who weren't at the event asking me why I was so slow, hehe. It's easy to armchair quarterback something when you are hundreds of miles away. The fastest TTC car was the CMC Camaro (1:48.069), followed by BJ's Mini (1:49.768 lap), then Herberto's RX8 (1:50.324) then my coasting time of 1:50.692 bringing up the rear. I suspect my first session times may have lulled some folks into thinking we'd be eating dust all day, but I honestly wasn't worried. Much.


So Matteucci and I got the car in the air on two jack stands and I crawled underneath to clean off the accumulation of engine oil, which wasn't much. A bit of brake parts cleaning and some blue shop paper towel and it was spotless underneath after 5 minutes. It wouldn't drip once the engine cooled off, but this was also wasn't something we could properly fix track side. The RMS repair would require removing the transmission, clutch and flywheel back at the shop. Once all that is out we could then assess the issue and probably install a "seal saver kit" for what is likely a ring scored around the back of the crank.

We went over the rest of the car and it all looked great - including tire wear (perfect) and oil level (still totally full). Brakes felt a little spongy but not enough to bleed yet. Warm tire pressures were 34-35 psi, which is right where the Hoosier A7/R7 "Tire Care Tips" article said to shoot for. After I noted that I had a bit of syncho "snick" going onto 5th gear, Brian adjusted the clutch pedal travel stop that he built, moving it a hair to allow for more clutch dis-engagement. These 3-plate clutches are tricky to set-up and a bit of a chore in the pits... I stalled it a few times until I got the hang of it. The release range is VERY narrow and with almost no flywheel mass the motor has less momentum - making it easy to stall at low speeds. But once at speed? Oh, yea it was worth it! You actually have to shift pretty quickly to allow the revs to match, otherwise the engine slows down too much and lurches even on upshifts.

http://vorshlag.smugmug.com/Racing-E...7_160106-S.jpg http://vorshlag.smugmug.com/Racing-E...8_101121-S.jpg

After checking multiple times that day the NASA scales were still not operational and we were told they would be down for the rest of the day. Knowing that we could have pulled all the ballast out but that would have been a douche move, so we left it all in and even topped the fuel tank off after each session, to keep the tank full and to count on the 120 pounds of fuel ballast. Limiting our runs to 2 hot laps, plus the out- and in-laps, the car was using 1.5 gallons of 93 octane gasoline per session. This was good to know since we were using extra fuel as ballast. I always wanted to be ready if the scales suddenly became operational - weighing under your declared minimum weight (3203) will DSQ the times from the session you just ran, as does a 4-wheel off or spin on course.

Matteucci was signed off for his TT license, since he had extensive SCCA club racing experience. Our "tactical plan" at the start of the day was that I would drive the first two sessions and he would drive the last two. But with the oil leak he declined to drive at all, and I changed my own plans to only take one or two hot laps per session, thereafter. The weather during the warm-up session was cold and I knew the track would get quicker once the sun beat down on the asphalt a bit, so I got geared up for the second TT session of the day, "TT Session 1", which I had hoped would also be my last for Saturday.

http://vorshlag.smugmug.com/Racing-E...DSC_6135-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6134-S.jpg
Just part of the 32 car Saturday TT grid, lined up for session 2

I was 12th on grid, right behind BJ's Mini, and was anxious to knock out a better lap. I still felt that the 1:46 lap I predicted was possible, I just needed to put it together and avoid any mistakes. I left a pretty big gap to BJ on the out-lap and didn't do any tire scrubbing. The R7s don't need any warming on this car, and they just work. I really REALLY like this compound and I am glad we made this choice. They wear well and grip was well past 1.2g lateral, in the data logging. Dyson Pham had something like 22 heat cycles on his R7s and still won TT3 on Sunday.

Went out and the first lap was a 1:47 and gobbling up the gap to BJ pretty hard. I went ahead and took a second hot lap and finally nailed the speed into and out of the big Carousel, which plays a big part in any lap at MSR-H. The speedo was showing 110 mph at the "Launch" (T13-14), 119 mph entering T6 on the back straight, and 113 mph entering the Carousel (T2) and 86 mph though that crucial turn. When I saw the AiM SOLO show my second lap at a 1:44.956 I knew that had reset the old lap record by nearly 6 seconds, so I took a cool down and came in.... with the biggest smile on my face in months. :D

Saturday TT Results: http://timingscoring.drivenasa.com/N...ston/Saturday/

After seeing the times from that session I noted that our car was the 7th quickest TT car out of 32 entrants so far. But then I noticed we only had 4 in class, so I went looking for a TT driver and instructor who hadn't run TT yet that day. Once you declare a class you have to stay there for the rest of the day. An old college friend Chris Ramey had been having fun in his TT1 Corvette on street tires, running in HPDE4 that morning, and jumped at the chance to take a ride into the #DANGERZONE! Ramey owns 4 Corvettes at the moment, including a C6 Z06, a C5 Z06, an '87 Z51 C4 and a Callaway Twin Turbo C4. Our TTC prepped C4 would be one of the slowest cars he had driven in a while, heh.

http://vorshlag.smugmug.com/Racing-E...7_142830-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6132-S.jpg

After getting the car reset to drive (jack up, clean oil, etc) and adding his registration as 192 TTC, attaching my second (battery powered) AMB transponder to the car and switched off the primary AMB, we had our 5th unique TTC entry. He strapped into the car and asked me what the target lap was. I knew Chris would be fast, and he has a tendency to go "Faster than you'd expect" so I told him to run a 1:46 lap. And asked him to only take one lap, due to the smoke. He got to grid for the 3rd TT session of the day and promptly put in a 1:46.165 time on his first and only lap, watching the AiM SOLO predictive timer closely. Normally I'd have told him to go for broke but he wasn't signed up with Hoosier contingency and I was, so we held him back... Chris told me he felt a 1:43 was possible. Yikes!
End of day Saturday TT Results - #DANGERZONE takes P1 and P2!

The rest of the TTC class didn't get much faster and the sun went behind the clouds right after that session, which cooled the track down. I felt fairly confident that the times would slow down in the 4th session and we sat out the last chance to put in a lap that day. That always makes me nervous but the cooler temps did indeed slow everyone down and my one timed hot lap for the day was enough to win the class, and Ramey's handicapped lap was still good enough for 2nd. BJ and Herberto got quicker after the Warm-Up and beat the fastest entry from that session, the CMC Camaro of Leinart, and every single TTC entry that day clobbered the old class track record.

The TTC win with 5 entries netted us 2 tires from Hoosier and 100 points for the regional championship. The Mini's time was still pretty close to Ramey's but about 1.4 seconds back from my time, so we were definitely keeping an eye on the Mini and the RX8 for Sunday. Anything could happen tomorrow, which was a whole new race.

http://vorshlag.smugmug.com/Racing-E...7_164303-S.jpg http://vorshlag.smugmug.com/Racing-E...7_164339-S.jpg

After Ramey's lap was done we got the car cooled off, up on jack stands, cleaned up the oil residue again, then bled the brakes (in the strange order you are supposed to on a C4) with some RBF600 and rotated the tires. We didn't need to do that last bit, but it didn't hurt and took no extra work. Chris had complained of a long brake pedal and he was right - the pedal felt like mush. Bleeding it didn't help much so it was something we'd have to keep an eye on all weekend and address back at the shop. The fluid looked perfect and the 4 corner bleed produced zero bubbles. Hmm. Matteucci found some RTV and pookie'd up the bottom of the bellhousing, hopefully slowing down the smoke - he was covered in black RTV when he was done, though.

http://vorshlag.smugmug.com/Racing-E...DSC_5923-S.jpg http://vorshlag.smugmug.com/Racing-E...7_180401-S.jpg
Left: The smoke looked like this after 2 laps, time to come in or risk a black flag. Right: Sunset Saturday at MSR-H

Very happy with the first result considering how little we did to the car. The tire wear was phenomenal even with only -2° front/-2.5° rear camber. Toe was 1/8" out up front and 1/8" toe in rear - Matteucci had strung the car himself and we left the alignment alone. The 34-35 psi pressures worked perfectly. The car was neutral if a bit loose, which is just how I like it. The brakes were far from perfect but replacing the 24 year old rubber brake lines might make a huge improvement, as would some real brake cooling (there just wasn't time).

The regular Saturday NASA party was great, with excellent bar-b-q and beer, trophies for the class winners, and pictures for the NASA newsletter. Dozens of people asked about the build and were amazed at the 1:44 lap time,and we had dozens more stop by the paddock both days wanting to see the car and admitting that they followed this build thread. After we had our fill of food we went back to the VERY dark paddock to load the car in the trailer... the trailer door was blocked. Hmm, car has no windows and I couldn't find anyone. After we left I texted Paul Costas and he added a blanket to the car to keep moisture/dew out - which we dubbed his "woobie". It looked hilarious the next morning, for sure.

Sunday January 18th, 2015 - Race Day 2

http://vorshlag.smugmug.com/Racing-E...8_072947-S.jpg http://vorshlag.smugmug.com/Racing-E...8_083233-S.jpg
Costas' woobie kept project #DANGERZONE warm and dry, hehehe

Matteucci was going to work on his C5 Z06 all day so I was on my own for Sunday, but Jaaon Toth planned to help me with the car in the paddock, plus he took a bunch of pics with my camera. I got to the track by 7:30 am, had tons of time, so I ran down to Buc-cee's and got breakfast burritos for everyone in our paddock area, a giant bag of ice for the coolers and filled up the F-350 with diesel. Was back by 8 am with the first session scheduled for 8:50 am.

http://vorshlag.smugmug.com/Racing-E...DSC_6174-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6243-S.jpg
Left: TT3 racer Joshua Garcia brought his Toyota 1UZ V8 swapped AE86 and had a blast. Right: An E46 330Ci which used to be mine

Figuring the first session would be cold again, and still needing an extra TTC entry, I asked TT driver/instructor Jason Toth to take the first session in the Corvette as TTC 192. Since Sunday and Saturday are separate races, using the same number as Ramey did the day before isn't a conflict. We strapped the extra transponder back on and he got to grid for the chilly first session. I was again hoping the same cars from Saturday would enter and give us five in TTC so the winner would get two tires, whoever that might be.

continued below

Fair! 01-26-2015 12:18 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued from above

Jason's lap was a bit compromised due to a TT3 car that spun right in front of him on his first and only hot lap, shown above. He backed off but drove through the smoke and took a sedate lap, putting one in the books and keeping out of trouble. He said he felt a bit rusty and jumping into a strange car with such a crazy clutch was a challenge. I appreciate the effort and it would probably only take a few laps for him to be right there on times, as I've raced with him for many years.

http://vorshlag.smugmug.com/Racing-E...DSC_6216-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6220-S.jpg

As the temps rose it started to smoke and it was dripping a bit when Toth went to the scales. The tech guys wanted to see the car again before we went back out so I took the car back to paddock, did the raise/clean/reseal trick after the car had cooled off. Once it was back to tech it wasn't leaking a drop and they cleared me for laps once again.

At this point I wanted to only take one lap and head home. A headache was starting (probably from sniffing brake parts cleaner for two days!) and looking at the weather it seemed that session 2 on Sunday might be the "golden session" where the best lap times of the weekend would end up. Got up to 70 degrees in the afternoon but was still low 60s for session 2.

Allan Page had run a 1:41.013 for a new TTB record in the morning but he also felt like session 2 would be faster. We weren't scheduled to go out until after 11 am, so we had a long break to reset the car. Meanwhile the sun did come out and warmed up the track. I got the transponders swapped back, got my suit and gear on, and went to grid sitting in P8 overall for this session, ahead of the rest of the TTC field and even some TT3 cars.

I was going to be putting in ONE hot lap, for the day, and it needed to be as perfect as possible. The goal was to go fast enough to ensure no other entries could touch the lap time for the rest of the day, so I could leave early with a little confidence. Ramey had predicted a 1:43 the day before but with the spongy brakes I wasn't sure. After frantically searching I realized that BJ had left Saturday night, apparently with a broken exhaust header. That left us with just 4 in class - Oh well, whoever won TTC today wasn't going to win any Hoosiers.


In the video above from this session you can see that the front of the field was really slow to take the green flag on the out lap and it bunched up the whole field badly on the straight before the Carousel. I was behind Dyson's TTB S2000 (running light and racing in TT3 for the day, trying to beat my old TT3 lap record and win that class). I wasn't sure about his power levels or times, other than he was gridded ahead of me so he had to be running quicker. Still, I backed off a bit on the run up to the Carousel.

Sunday TT Results: http://timingscoring.drivenasa.com/N...ouston/Sunday/

I had talked with the TT3 driver gridded behind me, telling him I was going to be taking ONE hot lap than I'd get out of his way. But he saw me back off of the S2000 on the out lap and passed me. Technically we're not supposed to pass on the out lap (double yellow) but it wasn't a big deal... other than I had to back off a lot into that turn before we began the hot lap. I tried to gap him enough to avoid this, but as we took the start/finish I was gaining on him and had to brake early into T17. Crap, I figured my lap was ruined, but then he nearly spun off track in T16. He had some spin issues that weekend and I was ready for that. Once he got it straightened up he was way off line and I snuck inside him with a clean pass and got on with my lap. I probably lost only a half second there, at worst.


That lap was great and the car felt hooked up everywhere. I still had plenty of driving mistakes like early braking into "the Launch" and probably the T6 corner off the back straight as well, but it was still my quickest lap of the weekend. As I came around for the start/finish on this first hot lap I felt like it would match Saturday's time but instead it was a solid 1.2 seconds faster with a 1:43.733. Booya! Thinking the pass slowed me down I took a second lap but it was slower at a 1:44.3. I didn't try to push my luck with a black flag for smoke so I backed off after that and came into the pits. Wootten was watching and sent me to the scales, warning me that this entry was under "special scrutiny" from the National level and if I was light my times would get bounced (which is normal).

http://vorshlag.smugmug.com/Racing-E...8_104105-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_6246-S.jpg
Before my session (at left) and afterwards (at right) in Impound, where I was scaled

I wasn't worried and just as expected I was 25 pounds over our minimum weight of 3203 pounds at 3228. That's exactly what I was shooting for - a big, safe margin of 25 pounds for this first event. For my first time to scales all weekend I was damned happy that our weighing and ballast had been perfectly in line on our scales as on NASA's. With constant fuel top offs after each session, this means we can run a good 15 pounds lighter next time (I'll always leave a 10 pound safety buffer over our minimum weight, at least).

http://vorshlag.smugmug.com/Racing-E...8_120855-S.jpg http://vorshlag.smugmug.com/Racing-E...7_160120-S.jpg

After I got back to paddock and changed into my street clothes I let the car cool down and then looked at the results and decided to skip the last two sessions. I still had that pounding headache and a 5 hour drive home to look forward to, so I started loading up the trailer. When the car was cool enough I drove it inside (which itself was a huge win!) and strapped it down, then said some goodbyes and hit the road. With a pair of wins, a track record reset by 7 seconds, two tires won on Saturday (only 4 in class Sunday means no tires were available), 200 points towards the class for the regional championship, and knowing that I was able to back up the smack talk. Whew, what a relief!


Allan ran his best lap of the weekend in his E46 M3 and reset the TTB record to a 1:40.805, which was almost exactly 3 seconds quicker than my new TTC record. The overall results for that session are here and it looks like we were 7th quickest for the day, out of a total of 38 TT drivers for the weekend (we had several new TT drivers added after Saturday check-rides). I'm very happy with that lap time, and never thought we'd only be two seconds off of our old TT3 lap record in this old heap, but the track was fast that weekend and 6 new TT lap records were set - many of them on the Hoosier R7.

New MSR-H CW lap records set this weekend:
TTE - Team Black Armor - 1:49.525
TTC - Team Vorshlag - 1:43.733
TTB - Allan Page - 1:40.805
TT2 - Bill Woods - 1:38.550
TT1 - Raymund Guerrero - 1:37.114
TTU - Paul Costas - 1:34.301

Only the TTD, TT3 (our's) and TTF records remain unchanged from 2013.

So that was our first race report - probably too detailed and boring for everyone, but I wanted to explain the extra entries/drivers in our car, the challenges we had with the brakes and rear main seal, as well as show some of the competition we're up against. It should be a fun year!

Thanks Go To...

Big thanks to the Vorshlag crew for busting ass and getting the prep done in such a short time frame. Also thanks Matteucci for helping me at the track Saturday and letting me crash at his place both Friday and Saturday nights. He never got to drive the car due to the smoke and I feel bad that he didn't get any seat time. Sucks more because as he has a WRL race at MSR-H soon coming up.

I also need to thank him for the top notch car prep he did on the car for the years before we bought it. Matteucci owned, built and tested this car for three years and did all of the non-safety prep that wasn't detailed in my previous posts here. So much "old part replacement" maintenance, gutting the interior, got the car light, the crazy 3-disc clutch, the oil pan, the new Opti and more. We were damned lucky to get a car this well sorted to start with, as the work he did would have taken months to knock out.

Event picture and video gallery: http://vorshlag.smugmug.com/Racing-E...-MSR-H-011715/

Five years ago Jason and I had seen the potential of this car and wondered why nobody had built one for TTC. When Matteucci wanted to build a TT car two years later I told him about the LT1 C4 in TTC and he jumped on it, found this car for a steal, and did all of this work to get it ready. After doing one RMS he found that it was leaking once again and just didn't want to mess with it - and neither did I, but I wish we had! I foolishly assumed it was something else, but was wrong. Would have been a much more enjoyable weekend without the smoke screen. ;)

What's Next + Remaining 2015 Race Schedule?

These are the remaining Time Trial competition events we want to enter with this car in 2015:
  • February 14-15 - SCCA Club Trials @ TWS
  • March 14-15 - NASA @ MSR-Cresson
  • April 25-26 - NASA @ TWS
  • June 13-14 - NASA @ Hallett Summer Shootout
  • July 31-Aug 2 - NASA @ Laguna Seca - Western States Championships
  • September 4-6 - NASA @ VIR - Eastern States Championships
  • September 26-27 - NASA @ MSR-Houston Counter-Clockwise
  • October 17-18 - NASA @ "TBA" (???)
  • November - NASA @ "TBA" (???)
You may notice that I have removed the USCA and Goodguys events from our season schedule. After some rules changes I strongly disagree with (that were actually aimed at our car), and what I felt was a botched Optima event in Vegas, we won't be trying to sneak Project DangerZone into these "street car" events - even though there are much more gutted, purpose built race cars racing in both. I'm going to give USCA another year to get the bugs worked out in their series before we jump into that circus again. We had only planned to do Goodguys in this car to test for USCA, and without a set of different wheels and 200 treadwear tires, the C4 isn't legal for either series at the moment.

Even though people think all we do here at Vorshlag is "work on Terry's cars" that is not at all the case. We had to squeeze in this prep in between customer jobs or after hours and only had time to do the basic safety prep, the brakes and tires, but just ran out of time to investigate the RMS, upgrade brake lines and fabricate the brake cooling this car obviously needs.

http://vorshlag.smugmug.com/Racing-E...IMG_3219-S.jpg http://vorshlag.smugmug.com/Racing-E...B61G5660-S.jpg
A dedicated track test like this is a MUCH better way to try out a new car BEFORE it is ever run in competition

And while this MSR-H NASA weekend was a great "Test" for us, and it was successful, the RIGHT way to do this would have been to get the car ready WEEKS before any competition event and test the car at a track somewhere, to work out the bugs and see where failures happen. Please don't take this one LUCKY example of us getting a car prepped in 8 days and winning/setting track records as the norm. It is not. Normally this quick-build process sans testing is a guaranteed way to look like a jackass and FAIL. But I'd rather be lucky than good...

The next event on our schedule is the SCCA Club Trials event, which we will likely miss. While I'd love to enter the Feb 17-17th event at TWS, which would be a great way to help that club grow it's PDX/Trials program and to test for NASA at TWS later this year, we're just too booked. We have some V8 swap projects we HAVE to wrap up for customers, plus the CNC machines are finally cutting metal, so Jason and I will be buried building hundreds of bits we need to fulfill backorders. There's no way we can work on #DANGERZONE in the next month so I have it stashed in my trailer for the time being. I will make NASA @ MSR-Cresson, however, and we will HAVE to do the RMS repair before that event.

http://vorshlag.smugmug.com/photos/i...-csJgmX5-S.jpg http://vorshlag.smugmug.com/photos/i...-kbDhKQk-S.jpg

We had talked about swapping the metal-puck triple disc pack for a Kevlar twin disc pack while the trans was out (for the RMS repair) but I kinda like the metal clutch now and I think we'll keep it. Front brake cooling and a new set of BrakeQuip flex lines will be built, for sure. We have found some clever ways to cool the brakes on a customer's C4 and we will employ similar tricks on this TTC build.


I'd like to address the body roll and brake dive this car has (see above), due to the stock swaybars and springs. The OEM replacement Bilstein shocks were also very "floaty" over the launch and anytime we touched a curb. The car handled like stock because it still had all the stock bits, but with 24 years of deterioration in many areas. The OEM rubber suspension bushings are disintegrated but we can replace those with non-metal bushings for zero points and $0 (Matteucci included a full set of poly bushings with the car). We still have 3 points left for mods - what do YOU think we should do with them? Here's a list of possible mods we might use the remaining points in TTC for:
  • Springs +2. This could be aftermarket or OEM springs outside of the BTM 1992-96 Corvette options
  • Swaybars +2. Burning two points would allow us to go with any aftermarket swaybar at both ends, providing its not cockpit adjustable
  • Shocks +3. This is an expensive way to burn three points considering we have stock bars and spring rates
  • Cold Air / Hood Venting +1. This is an unusual mod rule which allows all sorts of holes in the front bumper cover and hood for both cold air intake inlet as well as engine bay venting.
  • Headers +2 points. As much as I'd love to do this its almost impossible to add real headers without taking +1 for moving/removing/replacing the cars and +2 for after-cat exhaust changes. And we're already at the limit for power at this weight.
  • Adding 10mm of tire is +1 and adding 20mm is +3. That's tempting but I felt like we had more than adequate grip and tire wear was very good.

Give us your input - we'd love to hear what you think would make DangerZone faster. Remember: we have a very tight budget for purchasing parts and only 3 points left to play with in TTC. While I'd love to go nuts with an expanded TTB build of this car (and another 20 points of mods), that isn't in the cards this year.

Low Profile Build? Not So Much

This build thread has exceeded my hopes as far as how many people have read it (many thousands). We're posting it on 5 forums now (GRM, NASA Texas, SCCAForums, Corner-Carvers and Vorshlag) and I had probably 50 people talk to me at the NASA event and say they enjoyed reading it. One piece of potential bad news is that we now have some extra scrutiny at the highest level. We heard that the National PT/TT director Greg G has noticed our little build, as well as one other recently built Corvette TTC entry - Dave Schotz. Greg even called our TT director at the track and asked about our car. Uh-oh...


We know Dave from both his owning SCCAforums (one of the places we are posting this build thread) as well as his many previous wins in SCCA and NASA. We found out that he quietly built a 1991 Corvette and ran it in TTC for the first time a week before we ran our car. He told me he has always wondered why nobody built a C4 for this class, and when the tire points changed this year he decided to build one to replace his TTC Camaro (shown above in 2013, when he won THREE national titles in the same week!). With minor race prep and a set of 275mm R6 tires he has already racked up wins and a TTC track record at his first event. I won't say any more than that as Dave is likely to run his car at NASA Nationals West and he doesn't have "public build threads" like we do. If we can, we'll run our car at NASA Nationals East and hopefully NEVER have to run head-to-head with Dave... because he has a LOT of national championships. :D

Unfortunately this car Dave built, and our car if it does well, will probably get the C4 Corvettes a lot of scrutiny at Nationals and if either one does well, it might get these cars re-classed next year. I hope that isn't the case, and I expect that Greg will look at Dave's previous wins in a number of cars as well as the work we're doing before he makes any big changes. This car has been classed in TTC (and even TTD) for 5+ years without any alarm bells going off. Just a fluke that two serious C4 Corvette TTC builds happened to debut one week apart... what can you do? I'm just hoping we can make it through this season without any road blocks or rules changes... I like the car and want to continue developing and racing it for this season.

Until next time,

Fair! 04-09-2015 06:31 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
Project Update for April 9, 2015: Wow, I started writing this about 3 weeks ago (March 18th) and never finished. I lost the last 3 weeks to our new CNC machines, which I have been manning non-stop 24/7, trying to build a lot of parts to fulfill backorders. Somewhere in the last month - and I'm having trouble remembering back that far - we ran NASA @ MSR-C, and the weekend before that (COTA). We also prepped and took 11 cars to the Optima event March 28-29 at TMS, where I raced a C5 Corvette. Anyway, we took the TTC C4 and our TT3 Mustang to the NASA event, but I will break up the "race report" into another post. Let's look at the prep work that we managed to sneak into the C4 before this latest NASA race. It was a lot of work, but maybe not quite enough...

Roll Cage + Nets + Dash Rework Completed

About 3 weeks before the MSR-Cresson event I pushed the C4 onto Ryan's plate and he took over the front half of the roll cage fabrication plus the remaining safety gear that needed to go into the car before the next event. It took him less than 30 hours to do all of the work below. I wish this could have started sooner but our schedule is always packed and we can only squeeze in work on our shop cars when we get a small gap.

http://vorshlag.smugmug.com/Projects...B61G5233-S.jpg http://vorshlag.smugmug.com/Projects...B61G5258-S.jpg

The "back half" of the cage was built as a bolt-in roll bar, since we ran out of time to fully cage the car before the January event.

http://vorshlag.smugmug.com/Projects...B61G3496-S.jpg http://vorshlag.smugmug.com/Projects...B61G3494-S.jpg

We noted that my helmet was in a tough spot when making the 4-point roll bar in January, and as you can see above, any roof cage structure that was kept inside the window frame would be INSIDE my helmet. As it was the targa structure was touching my helmet - this car is narrow inside, up top. I didn't think me leaning at a list to starboard was the safe way to drive, so we pushed those upper cage tubes outside the window track.

http://vorshlag.smugmug.com/Projects...B61G5325-S.jpg http://vorshlag.smugmug.com/Projects...B61G5352-S.jpg

Will this affect airflow? Maybe. Will this positively effect drag reduction and top end speed? I highly doubt it, and nothing short of wind tunnel testing could prove it either way. Is it safer this way, keeping a piece of 1.75" steel tubing away from my helmet? OF COURSE IT IS. So we did it - its the safest, most common sense routing for this car and this driver. It looks a little odd, but its the right solution - this side of getting a shorter driver. My seat is already touching the floor - which we cannot alter.

http://vorshlag.smugmug.com/Projects...B61G5419-S.jpg http://vorshlag.smugmug.com/Projects...B61G5427-S.jpg

The front, upper cage tube near the windshield surround also follows that contour closely, again - to keep it away from my head. It sits as high up as possible, to prevent the cage from restricting my forward field of view. The unusual angle of the upper tubing junction there was later gusseted with more tubing, shown lower in this thread.


An "FIA" style vertical crush prevention bar is also added, which narrows the side door opening but makes the heavily raked windshield and A-pillar structure much more "pancake" resistant in a crash that put the car on the roof. I would like to keep my head and spine as delivered, thank you very much.

http://vorshlag.smugmug.com/Projects...B61G5444-S.jpg http://vorshlag.smugmug.com/Projects...B61G5542-S.jpg

Note the tight joint fit-up in the above right pic. After this point in the cage build (we missed taking pics of the door bars) pretty much everything was built and tacked in place, then the cage structure was completely pulled out of the car, in sections, to do the final welding.

http://vorshlag.smugmug.com/Projects...B61G5846-S.jpg http://vorshlag.smugmug.com/Projects...B61G5838-S.jpg

Sub-assemblies like the NASCAR-style door bars and load plates (above) were welded on the fab table, for easier access to get to the bottom of tubes. The FIA bar was welded to the A-pillar bar, things like that. Standing on your head to weld upside down inside a car is the suck.

http://vorshlag.smugmug.com/Projects...B61G5874-S.jpg http://vorshlag.smugmug.com/Projects...B61G5881-S.jpg

After the roll bar and cage sections were removed the B-pillar roof hoop was cut out of the car, lickity split. Yes, this was deemed necessary to gain access to the upper tubing joints for welding. The cage structure far exceeded the OEM rollover protection of this piece, and it was welded back in later. Luckily there was a body seam there that covers up the outer fiberglass cut. It won't have to be body worked.


The picture above skips ahead a bit, where the cage is almost fully welded and back in the car, and the roof structure hoop was welded back in place. At this point it is getting close to being done. The upper front corner gusset tubes are shown here, and yes, they do land on the FIA bar. It was another compromise to keep from having to cut a giant chunk of the already weak windshield frame away at the A-pillar. The roof diagonal is also shown in this top-down shot.

http://vorshlag.smugmug.com/Projects...B61G6292-S.jpg http://vorshlag.smugmug.com/Projects...B61G6297-S.jpg

The tubing above ties the front downbars into the firewall at one of the few places that has any metal. This is still a mostly fiberglass car, and the front half of the floor pans, trans tunnel, and most of the firewall is all just thin fiberglass. Can't exactly weld or land metal tubing onto that structure. So Ryan picked the farthest outer edge of firewall, which is metal at the base of the A-pillar, and tied some short pieces of 1.5" tubing from there to the main cage. This is to prevent TIRE INTRUSION into the cabin in a heavy crash, and for a car like this, well worth it. It doesn't pass through the firewall or tie into any major structure there. The upper OEM A-pillars are still free floating, since there is no roof structure (its almost identical to a convertible in this respect). With the OEM targa roof removed and the windshield out, the windshield surround is surprisingly weak and flexible. Oh well... we cannot tie into the A-pillar in any substantial way without taking more performance points for TTC/PTC.

http://vorshlag.smugmug.com/Projects...B61G6427-S.jpg http://vorshlag.smugmug.com/Projects...B61G6430-S.jpg

The door bars are pushed outwards to almost the skin of the fiberglass doors, and the factory impact beams were removed. This is to give a lot of ROOM to the driver's arms, and the extra room is appreciated. These bars have a lot of curves in them, to fit this crazy chassis, so they were tied into the outer frame rails in 2 additional spots, as shown above. This makes them stronger in a side impact, and the bars and frame would both have to deflect a lot to touch my arms. I'm rather fond of my arm and would like to keep it attached to my body.


Another thing the upper side cage bars do is go UPWARDS from the B-pillar joints/factory roof structure hoop, to give me more head room in a rollover. The seat is bolted right down to the floor, without a slider or any risers, to increase headroom. The only other trick left is to lower the floor - which costs performance points in TTC, which we don't have to spare. Everything in racing is a compromise.

Non-Cage Stuff + Safety Upgrades


Our friends from Titan Auto Glass (above) came out to re-install the windshield after the welding was complete. They had already been out a few weeks earlier to remove the new windshield they had installed in January - an added expense of doing the cage in two different time periods, with a race in between. Always, always get the windshield out of the way for a cage job.

http://vorshlag.smugmug.com/Projects...B61G6451-S.jpg http://vorshlag.smugmug.com/Projects...B61G6552-S.jpg

The 14" wide panoramic mirror from Longacre was mounted to fit my driving position. With the driver's side mirror I have an unobstructed rear view. The passenger side door mirror is broken and useless, for now.

continued below

Fair! 04-09-2015 06:31 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued from above

http://vorshlag.smugmug.com/Projects...B61G6275-S.jpg http://vorshlag.smugmug.com/Projects...B61G6313-S.jpg

The targa top was modified to fit around the cage. The metallic structure of the 22.6 pound assembly was removed, leaving just the outer skin. This wasn't ideal but necessary. The skinned plexiglass panel has the right curvature and was mocked up to make sure the windshield frame and B-pillar structure still fit.

http://vorshlag.smugmug.com/Projects...B61G6361-S.jpg http://vorshlag.smugmug.com/Projects...B61G6450-S.jpg

The roof panel mounts shown above were fabricated (and logged under the cage work) and welded to the top of the factory windshield surround and the top of the B-pillar roof structure. On top of each is a poly bushing, machined to the correct angle, bonded to the steel mount, and with a thru-hole for the mounting bolts. Mounting the plexiglass to the cage at only one end could allow the flimsy plexiglass to buckle under load, so the "flexible" OEM roof structure that was left was used instead.

http://vorshlag.smugmug.com/Projects...B61G6565-S.jpg http://vorshlag.smugmug.com/Projects...B61G6563-S.jpg

This plexiglass top mounts with flush mounted stainless bolts in 5 places and keeps the airflow going where it should, but that's about it. The top is still somewhat translucent, which isn't ideal, but it wasn't worth the time to fabricate this complex curved roof panel out of aluminum or even skinning the plexi in vinyl film. Yet.


While adding the cage, it made sense to add the nets and other safety gear required for wheel to wheel racing; this car could be run in PTC (W2W) as well as TTC (Time Trial). A Schroth center net was added first, and it passes through the dashboard surround that we added. As I showed in my first post, this car came to us with just the gauges attached to the fiberglass inner dash structure, but I wanted more of the original dash pad and gauge binnacle installed. It looks more complete and professional, plus provides better anti-glare protection. Ryan managed to save what he could from the old dash pad that came with the C4, clearanced that and the inner structure to clear the roll cage dash bar, and mounted the gauge cluster back in the original binnacle.

http://vorshlag.smugmug.com/Projects...DSC_5367-S.jpg http://vorshlag.smugmug.com/Projects...9_172746-S.jpg
Left: Before, with no dash pad or gauge "binnacle". Right: OEM binnacle added as well as about half the dash pad

A metal panel was added for a section and a toggle switch for the OEM traction control defeat was added. This really needs a momentary on/off push button but this works for now (it simply grounds a circuit) to disable the ASR. The driver's door net was a bit more complicated, as they always are. Ryan made a lower frame that has a slide-thru mount that can slip down and out of the way when unlatched, but gets rigid when the net is latched in place. The upper frame pivots at the back on a spherical, to allow it to swing down and in/out a bit.

http://vorshlag.smugmug.com/Racing-E...5_140504-S.jpg http://vorshlag.smugmug.com/Projects...3_170140-S.jpg

We added padding at the last minute, as the car was being loaded onto the open 2 car trailer - in the rain. I had hoped we would have time to paint the cage/interior at Heritage but we started about a week too late, as our shop schedule was just too overloaded. So we got to this point for safety...

Suspension Upgrade

After the cage work was completed by Ryan, Olof tackled the oil leaks next, starting about 3 days before the race weekend. In my last update I asked folks what they thought we should spend the remaining 3 points in TTC on: springs, shocks, exhaust, etc. We took this input and looked at the (somewhat limited number of) lap data from MSR-H and went ahead and decided: SPRING UPGRADE would be worth 2 of those 3 points.

http://vorshlag.smugmug.com/Projects...B61G6722-S.jpg http://vorshlag.smugmug.com/Projects...B61G6707-S.jpg

This base trim model 1992 C4 has the original FE1/FX3 springs (417 #/in front, 227 #/in rear - with wheel rates that are lower than that) with longer lowering bolts out back. Matteucci had already added the aftermarket shims/tricks to lower the front. It still sits very high up front, too. I was hoping to stick with Hyperco C4 springs at both ends, since we are a dealer, but their mold to make the C4 front spring was damaged last year and it would cost $70K to replace it. So yea, Hyperco is out of the C4 front spring business. I next called Paul at Vansteel and had a good conversation with him. He had better Hyperco data on the C4 than Hyperco, and recommended the Vette Brakes Products (VBP) "Xtreme" front spring, shown below.

http://vorshlag.smugmug.com/Projects...B61G6712-S.jpg http://vorshlag.smugmug.com/Projects...B61G6715-S.jpg

This VBP front spring is different from the OEM C4 style front springs, in that it is flat and has adjustable ends like a C5 front spring. He told me of a number of racers using this successfully and it was the one he used on most C4's like ours (track use). McCall also had good luck with this spring on his 1989 Corvette LT4 he runs in BSP class autocrossing. I've driven that car and it WORKS.

The C4 rear spring mounts with adjustable bolts at the ends, so you can alter ride height stock. Here are the OEM 1992 + 1984 rear springs

So then I called VBP and the guys there helped me narrow in on a spring rate for their front spring - which can be built from 1000-1250 pounds/inch. We decided on 1200 and they custom built a spring for us that measured out at 1170 pounds/in.

http://vorshlag.smugmug.com/Projects...B61G6630-S.jpg http://vorshlag.smugmug.com/Projects...B61G6623-S.jpg

For the rear I had picked up a 1984 Z51 rear spring from Matteucci with the car purchase, and it turns out to be the stiffest OEM spring ever offered on the C4 at 500-510 #/in. That end is easily ride height adjustable with these lowering bolts, which come in various lengths for extreme lowering. We stuck with the ones that Matteucci had and got to the ride height shown below. This is about 3" lower than stock up front and 2.5" out back, which lowers the CG significantly but doesn't get the rear suspension into any funky geometry (going lower can).


In case you were looking at the math, we increased the front spring rate by 2.8 times (417 to 1170 #/in) and the rear by 2.25 times (227 to 510 #/in), which is fairly typical of where we start for most IRS cars. Sometimes we don't go quite as far in the rear as we did here, but our spring choices were limited and I really like a car that "rotates well". I was not disappointed with the handling on track, either.

Oil Leak Fixes!

So our debut with NASA @ MSR-H had very limited laps due to massive smoke from leaks at the Rear Main Seal (RMS) and oil pan gaskets. We were limited to 1-2 lap blasts before the smallish oil leaks started to get on the exhaust and caused smoke. The oil drops stayed off the track - until you stopped, then it would miss the exhaust and drip straight down.

http://vorshlag.smugmug.com/Projects...B61G6630-S.jpg http://vorshlag.smugmug.com/Projects...B61G6623-S.jpg

Matteucci warned me before I bought the car that he thought both the RMS and oil pan gaskets needed to be fixed. He did the clutch job and Moroso oil pan install on jack stands, and it is nearly impossible to do those two things correctly on a C4 without a lift. The big Moroso oil pan has kick-outs for extra oil capacity and trap doors for better oil control while cornering - strongly recommended for LT1 motors on a road course.

http://vorshlag.smugmug.com/Projects...B61G6640-S.jpg http://vorshlag.smugmug.com/Projects...B61G6638-S.jpg

To get to the RMS the transmission has to come out, and that's no small task. Olof spent about 2 days doing this repair + the spring swap above, and it was finished at the last minute - we didn't load up and leave for MSR-C until 5:30 pm Friday (had planned on leaving by 12 noon to get a good spot).

http://vorshlag.smugmug.com/Projects...2_101954-S.jpg http://vorshlag.smugmug.com/Projects...2_102022-S.jpg

The C-channel/torque beam, driveshaft, shifter then trans were removed. Next the complicated QuarterMaster triple disc 7.25" diameter clutch pack and flywheel was removed, then the 3 pound starter flex plate. The weights are shown below.

http://vorshlag.smugmug.com/Projects...B61G6672-S.jpg http://vorshlag.smugmug.com/Projects...B61G6675-S.jpg
This is how you remove over 50 pounds from your flywheel/clutch mass. And this is what makes the motor rev!

We replaced the locking nuts on the clutch pack but put the sintered bronze plates back in, as the wear looked great. We had thought about swapping to their twin disc Kevlar "rally clutch" set-up, which uses the same cage and flywheel. This set-up is supposed to be more forgiving on slow speed driving (paddock, between rally stages) but I have gotten used to the triple disc and we decided to stick it back in since it looked good.

http://vorshlag.smugmug.com/Projects...B61G6649-S.jpg http://vorshlag.smugmug.com/Projects...B61G6657-S.jpg

The oil pan had some NASTY funk in it, which made us all VERY concerned. We found a hole in the intake boot that might have let some dirt past the air filter, but more than likely this is just normal wear. The grit was very fine, grey in color, and magnetic/ferrous, so probably indicative of worn piston rings. Well it made great power a month ago on the dyno, how bad could it be? We didn't have time to do a compression or leak down test, so I had Olof clean out the pan and slip in a fresh FelPro gasket and get it buttoned up. With the car on the lift and two removable subframe members removed it was easier to install it straight and true.

http://vorshlag.smugmug.com/Projects...2_102645-M.jpg http://vorshlag.smugmug.com/Projects...2_164208-M.jpg

We used the $300 LT1-specific RMS installation tool and got the new $10 seal installed square to the crank as well. Both the RMS and oil pan gasket had small rips in them, allowing the oil leak to happen. The exhaust went back on, fresh 15W50 Mobil1 oil and filter went in, and it fired right up. Runs much better with the hole in the intake boot and TPS sensor fixed, it seems.

Yep, the Throttle Position Sensor (TPS) and intake boot were both replaced. The TPS repair removed the dead spot I noticed at about 2200 rpm/light throttle, so that was money well spent. The factory intake boot is unique to the 1992 model year, and is no longer made. The closest thing we could find was the $50 silicone boot from Mid-America Corvettes, which isn't exactly like the (now out of production) stock piece, so we have to (temporarily) take a 1 point hit for Cold Air Modifications. We may or may not revisit that point later.

I updated the classing sheets for both the Corvette and the Mustang while the guys weighed the C4. We picked up about 45 pounds in the front cage structure (1.75" x .095" wall DOM) so they pulled one 45 pound plate out of the ballast box and away we went. We kept the same brakes, tires and other bits on the car from the previous race in January. No time to swap the rear hatch to plexiglass or anything else - go go go!

Time & Parts Budget To Date

I've been promising to show the hours and parts costs from the beginning but I write these posts when I have time and I have been very busy lately, trying to run the business and make CNC machined parts (feed the machines!). I finally stopped long enough to add up some costs. Let's look at hours first...

Hours Spent To Date = 104.94 hours, logged per MyShopAssist

I was guessing close to 100 hours and that was pretty dang close. We log all jobs, both customer work and our internal test mules and race cars. The only work not counted was my hours for installing the front brakes and cleaning the front suspension (about 4) and Jon's hours cutting and installing the decals (about 3). Here's the breakdown:

Round 1 - work before MSR-H
  • Mounting and balancing the R7 tires on the Enkei wheels = 1.02 hours
  • Install OEM replacement Bilstein shocks = 1.35 hours
  • First Oil + Filter Change (8 qts Mobile1 15W50) = .45 hours
  • Caliper + bracket + pin replacement for correct unit = .68 hours
  • 4-point Roll bar fab + cover plates + fire bottle install + floor pan repair + hatch removal/install = 51.23 hours
  • Sub-total before first race = 54.73 hours


Round 2 - work before MSR-C
  • Roll cage completion (front half + roof structure removal/install) = 29.23 hours
  • Ballast mount fabrication + machining = 5.32 hours
  • Oil pan gasket + RMS repair (+ driveshaft, torque arm, trans and clutch R&R and 2nd oil + filter change) = 11.19 hours
  • Front and rear spring installation (including fixing the VBP spring mounts) = 3.97 hours
  • Sub-total before first race = 49.71 hours

As for costs, its still around $5000 total, all-in. I will do a better budgetary break down next time, when I have more time to make the "report" in our accounting software. We lost our Operations Manager and it took me 3 weeks to look for and hire a replacement, who starts on Monday. It has been crazy busy around here and we've been down a man for 2 weeks, ugh.

This Week At Vorshlag - March 12, 2015

The video below shows a good bit of the work Olof tackled with the clutch, springs, and gasket/seal repairs. Its 7 minutes long and also touches on some other fabrication work + some of the CNC work Jason and I have been buried with for weeks.

YouTube video: https://youtu.be/iG3ZQ7gbFbk
SmugMug video: LINK

I've finally set-up our new Vorshlag YouTube channel and will start to post various videos there, as they seem to work better than our SmugMug video hosting (which seems to wreck the videos on mobile devices).


That's all I have for this time.


Fair! 04-23-2015 03:59 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
Project Update for April 23, 2015: Well the second NASA event in Project #Dangerzone did not go according to plan, but I had a bad feeling about the motor when Olof had the oil pan off and stuck a flash light up into the cylinders. I will cover the March Motorsports Ranch - Cresson event in the C4 below.


We also brought our TT3 prepped Mustang, so if you have read that car's latest build thread update, this NASA @ MSR-C "race report" section is verbatim from the massive four-part April 23rd update there. There is additional information below that race report about what's coming next on DangerZone...

March 14-15 - NASA @ MSR-Cresson. Running the '92 Corvette in TTC + '11 Mustang in TT3

Since we brought and I drove 2 cars for this weekend, this portion below will be shared in both the TT3 Mustang thread and the TTC Corvette thread.

Vorshlag Event Photo Gallery: http://vorshlag.smugmug.com/Racing-E...-MSR-C-031415/

We were pretty far behind on prepping the Corvette, and we saw some issues inside the motor with the oil pan off that worried me a great deal. Luckily I had signed our team entry "Team Vorshlag" up for a double entry with two cars (paid twice). This meant that Amy and I could both drive both cars in TT that weekend. So in case she wasn't winning in TT3, I could hop in the Mustang for a session and give it a go. Or if the Corvette had problems, which I suspected it just might, I could still get some seat time in the Mustang.


We didn't quite get the C4 prepped by the deadline I had hoped for, but our techs only work on Vorshlag owned cars when we have time between customer cars. Since we were slammed we had to squeeze in some time, but it was neither long enough nor soon enough. Since there was no time to track test the C4 after this big round of changes, this event would be the first time running this car with a brand new cage/nets, new spring set-up/ride heights, and then some items were unfinished. There were also some potential problems uncovered when we replaced the leaking rear main seal and oil pan gaskets.

http://vorshlag.smugmug.com/Projects...B61G6630-S.jpg http://vorshlag.smugmug.com/Projects...B61G6638-S.jpg
You can see a lot of the C4 prep in this "This Week At Vorshlag" video from March 12, 2015

Scoring in the bottom of some cylinders was evident. A thick coating of metallic grit was in the bottom of the oil pan, which was magnetic so that meant it was ferrous. Likely this meant we had smoked a piston ring or two (or eight). But when the oil pan and trans were buttoned up, the car ran fine and had no smoke. More importantly, ALL of the oil leaks were gone.

http://vorshlag.smugmug.com/Racing-E...3_170127-S.jpg http://vorshlag.smugmug.com/Racing-E...5_161741-S.jpg

The cage work was rushed and we ended up installing the SFI padding while loading the car onto Mike M's trailer at 5:30 pm, then loaded the TT3 Mustang into our trailer, and left the shop at 6 pm - about 6 hours later than I had hoped. It had been spitting rain all day but the predictions were clear for Sat-Sunday. We knew that this weekend was going to be crowded and both Mike and we were trying to get good paddock spots. Turns out it was a record attendance for ANY event at MSR-C with 220+ entries, many of whom got there early Friday to test, so we were parked in the grass when we arrived Friday evening. This made loading/unloading more difficult and we had to watch the splitter for scrapage on the paddock road, plus hot Hoosiers always got covered in dead grass when we came in off track.


We got Mike's 2012 Mustang and the Corvette unloaded off his open 2 car trailer, then our Mustang unloaded from our trailer right before dark. We then reloaded the Corvette (no side windows) into our enclosed trailer, since it looked like rain might hit over night. Amy, me and Mike unhooked the two trailers and we went to dinner in Granbury at the 1890, best restaurant in town. Amy and I stayed in Granbury at the Hilton Garden Inn, 15 miles from the track but it is worth the drive - not to mention the one hotel in Cresson fills up months in advance for race weekends.

http://vorshlag.smugmug.com/Racing-E...P7B_0472-S.jpg http://vorshlag.smugmug.com/Racing-E...P7B_7444-S.jpg

I'm glad we brought both cars. We got to the track early, then scrambled to get both cars ready without any crew to help (mistake). TT meeting was brief, check tire pressures and fuel levels, then I suited up and climbed into the C4 while Amy got ready in the Mustang. I went to grid and started mid-pack for the "Saturday Practice" session, which doesn't count for TT competition but the times are used to establish grid position. Scrubbed in the used R7 tires from the January event and they felt great. I got into a group with the front cars that quickly pulled away on the first hot lap, with nobody behind as far as I could see.


The C4 felt FAST and the handling was much improved with the new spring rate set-up, but there was a LOT OF SMOKE coming out of the exhaust. I knew it wasn't the RMS or oil pan, and it wasn't leaking oil, but definitely out of the exhaust and only when under power. I took 3/4 of this hot lap at speed and no oil was getting onto the tires so it felt fine, but I knew I'd get a black flag. I feared there was something seriously wrong inside the motor - broken piston ring or ring land? - and excessive blow-by was pumping out through the PCV system, into the intake, burning it in the combustion chamber, then sending it out the exhaust.

http://vorshlag.smugmug.com/Racing-E...P7B_9962-S.jpg http://vorshlag.smugmug.com/Racing-E...P7B_9131-S.jpg

I was driving my own line but watching the mirror for the exhaust smoke and watching the corner workers for black flags, thinking "Not AGAIN!", I lifted for the last 2 corners and coasted into the pit entrance way off the pace. This was somehow still a 1:25 lap, beating the old track record by 2 seconds. Coasting. GRR!

Video of the C4's first "throw-away" lap - which was the fastest it ran all weekend, and 2 sec ahead of the TTC record?!

After the Warm-up session my half-aborted 1:25.097 lap was was 9th fastest overall in TT and I was somehow in the lead over 5 other TTC cars in class, but the next closest car was only 1/2 second back. I knew this was going to be short lived and the time wouldn't stand because it was during the "practice" session.

http://vorshlag.smugmug.com/Racing-E...4_152231-S.jpg http://vorshlag.smugmug.com/Racing-E...4_134902-S.jpg

I figured we could fix the issue and make it back out later that day. After getting fuel (filled up after every session to maintain weight - even through it never got weighed), I came back to paddock and climbed out of the car (wearing the HANs was torturing my back on the way out of the cage each time). Amy pulled up, also in from the session early? She said the engine was cutting out BADLY, just like at COTA.

http://vorshlag.smugmug.com/Racing-E...598478_n-S.jpg http://vorshlag.smugmug.com/Racing-E...928118_n-S.jpg

So great.... now I had two broken cars to fix, when traditionally we have had near perfect performance week after week in the past 4 years. I started to think and remembered two years ago when the Mustang ran poorly at ECR in 2013 - it was a bad Wide Band O2 sensor. The front two O2 sensors are Wide Band and help the engine tune itself as it runs. The after-catalyst O2s just make sure the cats are working and don't do anything to the performance or tune.

http://vorshlag.smugmug.com/Projects...4_092731-S.jpg http://vorshlag.smugmug.com/Projects...5_090207-S.jpg

We had replaced both of these wide band O2 sensors before, but it had been 2+ years. So we changed out of racing suit and gear, started up the F350 and ran into Ft. Worth looking for parts. We rounded up a new Wide Band O2 at Ford Dealer (after trying 3 parts places), paying too much but happy to find it. Then stopped at Wal-Mart to get more Mobil1 for the C4, then at a NAPA on the way to get parts to try to make a remote breather/catch can for it as well.

http://vorshlag.smugmug.com/Racing-E...4_135518-S.jpg http://vorshlag.smugmug.com/Racing-E...4_141241-S.jpg

By the time we had gotten back TT session 1 was underway, but we had work to do. Parked in the grass we drove the Mustang up on the Race Ramps and I changed the O2 sensor, which was a back breaker, but it fixed the issue completely and it has run fine ever since. Initially I had hoped the C4 smoke was maybe a weird stuck PCV issue, so we pulled it out of the system and plumbed the crankcase to a big external breather. Sure enough, short test drives on city streets showed it was smoke free. After lunch on Saturday we took both cars out again, and Amy was fine but the C4 smoke was back, and worse than ever.


Amy was flying away from me as I took a single lap in the C4, immediately smoking. I came through Ricochet sideways at 100 mph, with a tiny bit of oil dripping out of the breather and getting onto the right rear tire. Doesn't take much! I immediately slowed down and pulled off line, waving drivers by. The smoke stopped but I was still getting waving black flags, telling me to come in for a "look". Pretty scary, horrible lap coasting and getting out of everyone's way. Called it quits for the weekend for the Corvette, as there was no fixing it track-side (needs engine internals).

http://vorshlag.smugmug.com/Racing-E...512612_n-S.jpg http://vorshlag.smugmug.com/Racing-E...926786_n-S.jpg
My temporary "breather mod" only made matters worse, so I shut it down after less than a 1/2 lap. "....MEH..."

http://vorshlag.smugmug.com/Racing-E...DSC_7008-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_7050-S.jpg

Amy went out and got it done, winning the class and two tires for the day. She let me drive a couple of laps in the Mustang in the final TT session at the end of the day, but it wasn't needed, and she won TT3 all on her own Saturday, with just one session driven in anger.

Amy likes using the curbs, eh? I kept calling her "Curby McCurbison", but there was zero damage

We put the Corvette back in the trailer since it looked like it might rain again, which was difficult due to the now lowered ride height of the C4, the angle of our paddock spot and the condition of my back. Lots of wood, ramps and cursing later we got it loaded.

http://vorshlag.smugmug.com/Racing-E...4_201123-S.jpg http://vorshlag.smugmug.com/Racing-E...4_193700-S.jpg

The Saturday night NASA party started at 6pm and we all had some great food and drinks while they handed out trophies, took pictures with the NASA trophy girls, and all that. We also got our 2014 Regional TT3 championship trophy, since we missed the NASA banquet a few weeks earlier due to a different March ice storm (Thanks to Al Gore!)

Sunday we got to the track at 7:30 am. Unloaded the C4 again to make room for people in the trailer that day (great shelter from wind and sun) and we got Amy ready for TT session 1 in the red car. We forgot to refuel after her stint so I went to grid in TT session 2 with less than 1/2 tank, making it fuel starved badly. With the downforce the car makes and speeds in Big Bend and some other corners making for lots of lateral g-loading, we have to run 3/4+ tank of fuel, minimum. I fumbled my way to a 1:19.8, fuel starving for 3 laps.

http://vorshlag.smugmug.com/Racing-E...DSC_7095-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_7104-S.jpg

After I fueled up the car fully, I went out again in TT session 3 after lunch, when the conditions were a bit worse. I ran a 1:19.1 in two laps before catching traffic, but by then the front tires were DONE and it was pushing badly. These well used front tires were not good enough for two drivers both days, so I was almost 2 seconds off my 2014 pace (on sticker tires). That's rule # 1 in racing: TIRES MATTER MOST!


I had a 1:19.4 on day 1 and got it down to a 1:19.1 on tires beyond "end of life" on day 2, so I guess that's some progress? Amy went out in TT session 4 but the tires were all gone by then and the times were off pace. We loaded up both cars onto both trailers by 5 pm and were on the road home by 5:30, tired but happy to have won the class both days. Amy got her first legitimate TT3 win on Saturday, so she was ecstatic. I was bummed about the C4, and my "practice session" 1:25.0 time (good enough for 2nd by only 2 tenths, and it was an ABORTED lap!) was bounced since it was the lone practice session, so I ended up down in 5th place on Saturday using my "smoking, limping, black flagged lap" in TT session 2 on Saturday, bah.

continued below

Fair! 04-23-2015 04:11 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued below

http://vorshlag.smugmug.com/Racing-E...P7B_7448-S.jpg http://vorshlag.smugmug.com/Racing-E...P7B_3178-S.jpg

So that means no worthwhile points for the TTC entry, but two solid "100 point days" for our TT3 entry, if we end up having the Mustang all season (it's still for sale). Four fresh Hoosier A7s (in the right sizes this time, yay) were won here, so we'll have fresh tires on the Mustang at TWS in April. The original set of 245mm R7s still only have about 8 laps on them in 2 race weekends and look great, so we'll run those on the C4 again at the next event (only won 2 new tires at MSR-H in this car).

So the smoking issue and metal in the oil pan can only mean one thing: the the 24 year old LT1 motor needs to be rebuilt. That's two events in a row smoking and/or leaking oil in the C4, and I don't want to get a reputation for that nonsense. I want the motor rebuilt, back in the car, re-dyno tuned, and a track test day completed before #DangerZone goes back to a NASA event.

http://vorshlag.smugmug.com/Racing-E...IMG_1107-S.jpg http://vorshlag.smugmug.com/Racing-E...569896_n-S.jpg

The Mustang must have been weighed 4 or 5 times all weekend, but it was never close to being underweight. We gained some weight somewhere, as it was always about 70-90 pounds over the 3802 pound minimum all weekend, but I kept taking ballast out until we were closer. The C4 only made two laps, in two sessions, so it never had a chance to get called to scales. It was well over the 3203 pound minimum, as I kept topping off the fuel tank and the added mass of the front cage section was also present.

http://vorshlag.smugmug.com/Racing-E...s3-14-15-M.jpg http://vorshlag.smugmug.com/Racing-E...s3-15-15-M.jpg
Left: Saturday TT Results. Right: Sunday TT Results

Official Results: http://timingscoring.drivenasa.com/N...MSR%20Cresson/

Last up, some in-car video from the Mustang, shown below. This was with a suction-cup mount on the windshield, instead of the roll-bar mounted I/O Port mount usually located behind the driver. I moved that to the C4 and should really just buy another one to keep in the Mustang. It makes for a better view and shows the driver issues (flailing around like I usually am).

In-car video of the TT3 winning lap in the Mustang

The lap timer fell off it's windshield mount, so I was driving "blind" without predictive lap times. I hate that, and never want to drive on track without the predictive timing from the AiM SOLO. That 1:19.1 lap was a solid 1.8 seconds off my 2014 pace here (1:17.310, still the TT3 lap record) in the same car, but that could just be the difference between a sticker set of Hoosiers vs a very old and worn set. It was still enough for the win in TT3 and 4th fastest for the day in TT. We had 6 cars in class on Saturday and 5 cars in TT3 on Sunday. Amy was quick Saturday but was off the pace Sunday, when the front tires fell off. Glad she let me take 2 sessions in the car, because we needed it. Still won by nearly 2 seconds but it would have been a tenth or two short with her late Sunday times.


On the photos - we took pics with our Nikon and my potatocam phone, but thanks to MohFlo photography for the shots they got (bought the digital files) and also to Jason Toth for the images he shot. Their stuff was way better than anything Amy or I took (maybe the one above was OK, which was from my potatocam). And the next time I want to bring to cars to race and DON'T bring any Vorshlag crew to help, somebody kick me in the head? That weekend was a lot of scrambling around, and I'm too old for this crap. ;)

New Motor + Potential Protest?

Apparently my publicly posted forum build thread got somebody fired up and there has been a protest made to the National level, which I am assured that I will lose. It has to do with a few tubes in our roll cage design, which are deemed performance enhancing. Of course we can remove or re-route before the next event, but I am going to appeal the two issues. If we lose that at least we have time to correct this before the next event - where we could have lost points or gained a DSQ. :)

And before some of you call this nit-picking, I'm glad we found out about it before going to NASA Nationals and getting bounced there.

http://vorshlag.smugmug.com/Projects...B61G6294-S.jpg http://vorshlag.smugmug.com/Projects...B61G6427-S.jpg

As for the motor, there are very clear guidelines in the TT rules on what is allowed and what costs points. As usual we will build the next motor to the limit of the rules, within the budgetary constraints we have set, and try not to make any more power - as we are at the limit right now.


I am also trying to round up a factory 1995-95 LT1 wiring harness and computer, which we can legally swap to if we do the swap completely replacing the 1992 EFI system. This newer computer will allow for BETTER TUNING on the motor, as the 1992 is a one-year-only set-up with very small number of EFI parameters that can be altered. Sean at True Street said the 1993 model year was a big jump up (nearly double the parameters) and the 1994-95 has even more things he can tweak. This will hopefully help de-tune any power we might make with a fresh motor as well as allow the engine run smoother. Still, the fresh TPS sensor and repairing the giant leak in the air intake tube already made a MASSIVE improvement in driveability and smoothness under power at MSR-Cresson.

That is what is so strange about the last event - the motor was pulling hard and the car ran strong, other than the massive clouds of smoke coming out of the exhaust. What is it they say? A motor runs best right before it blows up! Well this one didn't scatter, so hopefully the stock crank, block and heads can all be re-used when Erik Koeing at HK Racing Engines gets his hands on this 24 year old longblock. I'll have Olof do a compression check before it comes out (next week) and gets shipped to HK.

What's Next?

There are a lot of events we will be at in the next few months, but the first time we'll likely be able to run the C4 in anger is June at Hallett. And of course I want a dedicated track test that is successful and oil/smoke free before we go there. The shop is slammed right now and I'm trying to squeeze DangerZone on the schedule to have the longblock pulled.

We also need to do some.... test fitting of drivetrain parts... for a customer's upcoming C4 build. This will be the first of its kind, ever built in a C4. Its so crazy I can't even talk about it. Gotta finish his C5 build first, though.
  • April 24-26 - NASA @ TWS
  • May 2 - Cars & Coffee Dallas
  • May 3 - SCCA autocross @ TMS Bus Lot
  • May 9 - Five Star Ford Track Day @ ECR
  • June 13-14 - NASA @ Hallett, "Summer Shootout"
  • August 23 - SCCA Solo at Lone Star Park
  • September 4-6 - NASA @ VIR - Eastern States Championships


Since the C4 is down, we just finished the track prep and loaded the TT3 Mustang in the trailer. Amy and I are about to head down to TWS for the last NASA event ever at this track, this weekend. Its being plowed under soon to make suburbia even more crowded, yay.

Until next time,

Fair! 05-26-2015 12:19 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
Project Update for May 26th, 2015: Its been pretty busy around Vorshlag and I've been buried in the CNC room, but with a bit of extra help in there for the summer I can finally sneak into my office and write a few project build forum updates.

This Week at Vorshlag for May 8th, 2015 - including a bit on the C4 at the 6:40 mark

We haven't had time to work on the C4 other than extracting the drivetrain. Again, we only work on our "shop cars" when we have a gap in our customer work schedule, which hasn't existed. So I snuck the C4 in line for a few hours of shop time and had the guys yank the motor and it was sent off to be rebuilt. We've also had more conversations about "the internet protest", which was actually FIVE things, and we're aiming to fix all of those before our next event. I will go over some upcoming car prep and document the issues of the protest in great detail.

Motor Rebuild Time


Yep, after 24 hard years this old LT1 has seen better days. Too much crankcase pressure makes for excessive blow-by and smoke, which precludes us from making a lap without a black flag. There's not much to share in this section other than the motor is finally out and shipped to the engine shop, and how that came to be.

http://vorshlag.smugmug.com/Projects...DSC_7776-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7785-S.jpg

With but 6 weeks until our next event, I couldn't wait for an opening in the shop schedule any longer, so I asked Brad and Ryan to get that LT1 out of the car as quickly as possible on May 6th. Within a few hours the drivetrain was out and the motor was on a pallet, ready for truck shipment the next day.

http://vorshlag.smugmug.com/Projects...DSC_7793-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7791-S.jpg

After pulling the driveshaft, c-channel drivetrain brace, transmission and shifter out, they could finally lift the motor out of the engine bay. Its a TIGHT fit in there, with a cross brace right next to the front balancer. Its almost impossible to stab the motor and transmission into the car tied together, unlike in some other cars.

http://vorshlag.smugmug.com/Projects...DSC_7796-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7799-S.jpg
A sharp-eyed reader noticed the "throttle body airfoil" (top right), which we don't have points for. Its coming out.

The motor was stripped down to the basic long block, it was bolted to an engine stand I had built years ago for easy GM V8 transport. Many LS1s have been shipped on this shipping stand, but this is the first LT1. This frame was then bolted/strapped to a pallet, wrapped in plastic, and all 480 pounds was shipped to the guys down at HK Racing Engines in La Grange, Texas. One thing someone on Facebook noticed in a picture I posted (and called me to warn me about, thanks Dave!) when the engine was out was an aftermarket "airfoil" in the throttle body. With a 24 year old car, sometimes a previous owner's mods get missed. No excuses - this airfoil is coming out. We want this car to be PERFECTLY legally. Squeaky clean. As a business owner in motorsports I cannot afford to be caught cheating in competition, and I'd rather lose a race than knowingly break a rule.

http://vorshlag.smugmug.com/Projects...DSC_7804-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7828-S.jpg

HK has pulled the top of the motor apart and told me "it all looked fine". By now they should have some .020" overbore replacement pistons, rings, bearings and valve springs ordered, which should freshen things up a bit. I think they will find some broken piston rings when they tear the bottom end apart, since we noted a lot of scoring in the bottom of a few cylinders as well as "too much" ferrous metal grit in the bottom of the oil pan.

http://vorshlag.smugmug.com/Projects...DSC_7806-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7803-S.jpg
I'm going to clean the living snot out of the engine bay while the motor gets rebuilt

Erik Koenig is a master engine builder, and also a damned good racer. I raced with him for a couple of decades and he knows how to read a rulebook. I sent him the pertinent pages, we discussed what we can do (and what we cannot) in TTC, and he's all over it.

Our TT3 prepped Mustang sold in June 2015

Problem is that I didn't give him a lot of time, so making the June 15th Hallett event is going to be tight... if the motor isn't back in by then I'm NOT racing our TT3 Mustang at Hallett (it is very much for sale!) Yes, this TT3 car has won 4 tires every time we have shown up to a NASA event in the past 2 years, and did so again a few weeks back at TWS - winning by a huge margin after taking only a single lap on Sunday - but that car is out of competition, for me. :( If you know of anyone potentially interested, please send them to this link - Thanks!

No more "back up ride" in the TT3 Mustang, as it still has perfect paint that I want to protect for the next owner!

So, I've already used my "4 drops" in TTC for the regional championship, so if we miss this June Hallett event in #DangerZone I'm just not going to worry about TTC regionally for this year. With our summer break coming, we won't have another NASA Texas event after Hallett before NASA Nationals East, so I will have to go to an out-of-region NASA event or use non-NASA events to test the car before Nationals. I've still not had more than 2 laps in a row in this car all season, dang it.

Changes Planned To Be 100% Legal

I mentioned a couple of the things that I was told were protested against #DangerZone in my last post, but have since seen a more complete list of items in an email from Greg Greenbaum, NASA's National TT director. In private correspondence Greg passed on an alarming number of things that some reader of this build thread wrote in about to protest (five).


As I mentioned before, some are cage issues - three in fact. One was a very picky, gray area issue that I have been "all but told" is allowed on this car, for safety concerns in this narrow cabin. As I showed in a previous post (again, I am hiding nothing) parts of the roof side bars next to my head are a hair outside of the window plane, but otherwise they'd be inside my helmet. I can't sit any lower without going through the floor, either. Its this way or no cage, and after my accident last year I'm not keen on driving un-caged race cars.

http://vorshlag.smugmug.com/Projects...-changes-S.jpg http://vorshlag.smugmug.com/Projects...B61G9085-S.jpg
We always tie in both sides of "NASCAR" door bars to the frame, for symmetry and safety. But in NASA TT-letter classes it is +2 points

The other two cage issues are shown to be illegal in the rules... sort of. First, the passenger side door bars clearly cannot be tied to the frame even though they are allowed on the driver's side (up to 3 places). I read the rule wrong, where it said "drivers-side" I thought "both sides", stupid mistake on my part. It still seems odd that the cage rules would make for an "asymmetrically safe" cage. So our plan of putting a passenger seat in this car and taking riders is out, since we can't make the right side of the cage as safe as the left without taking +2 points (and bumping up a class). Easy fix with a saw and grinder.


The third and most unclear of the cage protest rulings has to do with the two optional tubes that the TT cage rule above states can be added to the firewall or foot well areas. Our two tubes are apparently placed too high to be called "tire intrusion protection" (but the rule says nothing about tire intrusion, of course, that is something you have to assume). What the rules wording does say doesn't match of what the rules makers meant, however, as I'm told after this ruling that it should read as follows:


Originally Posted by what they really meant to write
"Two additional attachment points for either two foot-well bars or two bars to the front firewall BELOW THE TOP OF THE TIRE (one on each side) may be added without TT Modification Point assessment".

http://vorshlag.smugmug.com/Projects...B61G6294-S.jpg http://vorshlag.smugmug.com/Projects...B61G6507-S.jpg

The "below the top of the tire" bit was what I was told is inferred in this rule. Shame on me for not knowing that. The two NASA race directors I showed this cage layout to thought we had them in the optimum place, but they were also wrong. So apparently we have to read and interpret the rules then always ask for a clarification for anything (or risk a DSQ at an event). You were warned: there are the written rules and then there are the unwritten rules. Again, this is an easy fix - We will cut those two tubes out, move them down below the top of the tire, weld them back in place, and then be double-secret legal. :D

http://vorshlag.smugmug.com/Projects...DSC_5522-S.jpg http://vorshlag.smugmug.com/Projects...DSC_5544-S.jpg

Item four brought up in the protest was our upgrade to 1996 Corvette Base Trim Level front 13" disc brakes, over the 1992-95 BTM 12" front discs. Again, we did our homework and found that all 1996 model Corvettes came with the 13" diameter fronts, which used to be an optional upgrade on base coupe Corvettes from 1989-95 under the Z07 or Z51 options. But since this car is listed on the same line as all 1992-1996 Corvettes, non-LT4, non-ZR1, we can "update" to the 1996 base trim brakes for zero points (normally +2). Yes, its a loophole but hundreds of racers look for loopholes to exploit - that's called racing. Luckily the National office agreed with our documentation here and disallowed that particular protest.

Shocking Thing About OEM Shocks

The last issue that is being ruled against (item 5) has to do with the OEM Bilstein vs the replacement Bilstein dampers we used, which I am gonna lose. See, we don't have the points left in our TTC class points budget to add better dampers (+2), so we elected to stick with the OEM units and changed spring rates instead at +3. That was a gamble that some thought was strange, since we could have done double adjustables shocks (which we sell) for +2 points instead of springs (we don't sell the VBP spring).

http://vorshlag.smugmug.com/Racing-E...DSC_5821-S.jpg http://vorshlag.smugmug.com/Racing-E...DSC_5807-S.jpg
This was how the car looked while cornering on the B6 Bilsteins + 245 R7s + stock bars and springs.

After driving the car on the 245mm Hoosier R7s at MSR-Houston (above), with the B6 Bilsteins and stock springs, then looking at these pictures... I felt the car had too much roll and dive. Sure, we could have gotten some of that dialed out with adjustable shocks ($3350 MCS monotube TT2 doubles), but probably not as much as I'd like. Tripling the front and doubling the rear spring rates made a bigger change, in my view (and I drove it this second way at MSR-Cresson), so we took a gamble and went that route. I will just have to deal with the less-than-ideal damping offered by the stock replacement Bilsteins. Ideally, of course, we'd change BOTH the spring rates and shocks. That is if we had the points budget, which in this case we just don't. ALL the rest of our points are for the tires - because TIRES ALWAYS MAKE THE BIGGEST IMPROVEMENT IN LAP TIMES.

http://vorshlag.smugmug.com/Racing-E...8_120911-S.jpg http://vorshlag.smugmug.com/Projects...B61G3572-S.jpg
Tires matter SO MUCH and virtually everything we do to the suspension is just to keep the tires happy

So, let's look at the OEM shocks. As I stated before, this 1992 model Corvette base model coupe came with Delco-Bilstein 46mm piston monotube dampers at all four corners, and amazingly the 24 year old original shocks were still on this car when we got it. Unfortunately, two of them were blown, which is to be expected after nearly two and a half decades of use and abuse. So we purchased replacement Bilsteins as close as can be purchased today, and put them on for a "zero point" replacement.

Wrong. Not the original dampers, not legal. This is what the ruling was on item 5.

continued below

Fair! 05-26-2015 12:22 PM

Re: Vorshlag Budget TT Build: Project DANGER ZONE
continued from above

http://vorshlag.smugmug.com/Projects...B61G3595-S.jpg http://vorshlag.smugmug.com/Projects...B61G3593-S.jpg

Could we have rebuilt the OEM Delco-Bilsteins instead? Sure, but there were two problems with this idea. First, the time frame we had to build this car back in January (2 weeks) wasn't going to give us enough time to have the old shocks rebuilt. While we are a Bilstein Motorsports dealer, we still don't have the $5000 fill rig necessary to refill the Nitrogen charge in this particular style Bilstein (and that's all it works on). Secondly, if we had said we had these shocks rebuilt, who would have believed we had kept the OEM valving?? We make and sell shocks for a living! That would have been the first thing people assumed - shock guys, cheater rebuild.

http://vorshlag.smugmug.com/Projects...DSC_7878-S.jpg http://vorshlag.smugmug.com/Projects...DSC_7880-S.jpg
These have been sitting in a box in my office since January, in case we were forced to rebuild and use them.

The proof about what came in the 1992 model base coupes is shown below, which are some pages from GM documents which I haven't shown before (Jason researched and found this cache of GM documents for the 1992 model Y-body). There are hundreds of pages of period documents on this version of the C4, so have fun digging.

http://vorshlag.smugmug.com/Projects...standard-M.jpg http://vorshlag.smugmug.com/Projects...ilsteins-M.jpg

We knew these Delco-Bilstein monotubes were the stock dampers but apparently some folks didn't even believe that. So I'm showing this now, since I was warned that I'd lose a protest even if we put these old blown out shocks back on without showing documented proof of the OEM fitments. Guilty until proven innocent, but I guess with a build shown this publicly I should expect this level of scrutiny.

After looking for the exact OEM replacement shocks back in January we found that we could no longer buy these Delco-Bilsteins anywhere, for any amount of money. Not from GM, not from Bilstein, and there were no "New Old Stock" dampers available anywhere (if you find any, please send the link my way!). So, from my SCCA background on similar "stock replacement equivilent" issues we "assumed" that a close alternative replacement to the OEM dampers would be allowed. So we looked and found a set of shocks that were the closest and still available new: Bilstein B6 monotube dampers that are listed in the Bilstein catalog for the 1992 base trim level Corvette. These are a whopping $85 per corner, retail, and we paid less that that with our direct dealer account.

http://vorshlag.smugmug.com/Projects...stein-c4-S.jpg http://vorshlag.smugmug.com/Projects...kauto-c4-S.jpg

And while I didn't go into this excruciating level of detail before, I hid none of this. We showed these B6 dampers in one of my first posts here, but I didn't show that there are about a dozen choices for the C4 from Bilstein... they make some for the base model, others for the Z51, some for different years, there's a B6 and a B8, and of course fronts and rears. This array of cheap Bilstein monotubes is what we chose from to get the two part numbers shown for the 1992 base model coupe, shown above left.

These are painfully similar to the OEM Delco-Bilsteins - they have the same 46mm pistons, same 50mm body diameter, the same shaft sizes, same body dimensions, and no external valving adjustment. You can see the details in the images below, which were captured from the "GM Heritage Center" database of records for 1992 model Corvettes at this link.


I have cleaned up these scans from 24 year old literature published for this 1992 model Corvette, and even highlighted the mention of Delco-Bilstein (its referenced on 6 different pages) and even the dimensions of the shocks. And the swaybars - which are still the OEM units. These Delco-Bilsteins are functionally identical to what we have been using (the $85 B6 dampers), but that's not good enough to be legal as +0 point shocks, they have to be the actual 24 year old Delco-Bilsteins, which we'd need a TIME MACHINE to get a hold of a new set in 2015.

GM doesn't keep original stock parts on hand for more than 10 years, but they instead have a "generic replacement part number" that supersedes the original 1992 shock part numbers. This replacement part number is shown for all 1989-1996 Corvettes without the adjustable (FX3) dampers. Its a $28 piece of crap twin tube shock that is so dissimilar to the 1992 model OEM damper that its almost funny. Not gonna happen on my car, no way.


Anyway, long story short - we are now sending the old and blown OEM dampers (shown above) directly to Bilstein, having them rebuild them, and then asking them to include documentation that they didn't alter the valving in any way. I'll have them seal the shocks in tamper-proof tape if they can, too. And someone will probably still accuse us of cheating, oh well. These "cheater" B6 Bilsteins will be for sale here soon after - cheap!


I wish I could take people for a ride in this car on track with these B6 Bilsteins. Well, with no right seat that ain't gonna happen. Any way, the C4 on these shocks rides like a big underdamped mess at speed. This is not a great set of dampers, not by a long shot. But they are just the closest thing we can find to OEM that isn't leaking. At $85 per corner, you get what you pay for. But that's not good enough - I have to use actual OEM shocks, not OEM replacements, or take +2 points (and move to TTB). And the burden of proof is on the DRIVER.

Whatever the answers to life's big questions, we're going to make SURE this car is squeaky clean at Nationals. If I get protested over some bullsh*t non-performance hidden rule detail, I'm going to share it here for all the world to see. Hopefully, after this 5 part protest and the resulting changes we will make to 4 items, it will be smooth sailing from here on out.

What's Next?

We're desperately trying to get the motor back and installed in time to make Hallett June 13-14, but time is not on our side. I'd also like to get the following changes, modifications and completed before NASA Nationals East:
  • Since my red Suzuka trade fell through after the fact (not my fault), we have to install a new driver’s seat (black Cobra Suzuka GT width Kevlar seat just arrived)
  • Add a massive oil catch can + breather system to the motor
  • Add aftermarket oil pressure, oil temp and water temp gauges
  • Install poly bushings throughout + machine offset Delrin bushings where needed
  • Design and build front brake cooling + new braided brake lines
  • Build support frame for rear plexiglass hatch and install
  • Move full sized battery to rear cubby hole + rewire main battery cable with main power kill
  • Make aluminum covers for ABS and battery cubby holes
  • Take car for interior paint + cage paint, exterior repairs + left side and front end paint
  • Complete the new livery package with stripes #RAMPAGE
  • Spend last point on proper custom cold air and hood venting

Lots planned before Nationals, and some of it might be protest bait, so we might hold off if it seems unnecessary. Again, the way that the internet protest went down was a bit weird, but look at this build thread - the pictures, the details I'm sharing, the SMACK talk in my first post? I probably should expect this level of scrutiny more often.

That's all for now - will update once the motor is back! Thanks for reading,

All times are GMT -5. The time now is 11:20 AM.

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.