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Vorshlag C4 Corvette TT Build: Project DANGER ZONE

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  • Fair!
    replied
    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above



    That's where I had Olof place the inlet ducts. "Just drill a 3 inch hole and bolt them in right there", I told him. The inlets are directly underneath the factory headlight holes, taking in high pressure trapped under the nose that isn't being fed to the radiator inlet. There's ample room under the hood (with the flip-up headlight assemblies gone) to route the hoses up and over to the brake backing plates.



    Due to concerns Jason and I both had about air pressure bleeding off laterally towards the edge of the nose and bypassing this brake cooling inlet, I had Olof make a little aluminum "brake canard". This is a little air dam that forces some air into a closed pocket to feed the brake inlet. Yes, I know this might incur some aero penalty for TTC. We are going to test with and without these in place and we will add rivnuts in place of the rivets used to attach these little air walls, so we can test with and without them installed.



    The brake hose routing looks fairly straightforward, but of course we haven't tested it on track yet. It might rub the wheel at full lock, but since the car is still in the air with the wheels off we haven't checked that yet. A piece of the plastic inner fender liner was trimmed to route the 3" hose below the top of the wheel, but we will see how it fits when the wheels and tires are mounted and its back on the ground.



    Last but not least the car is getting a new set of factory lower air dam plastics. Again, we bought these many months ago just never got around to it. The old bits are beat up and the left sides is held on with Gorilla snot and is half falling off. The new air dam bits will help push more air into the waiting duct for the radiator or the two brake inlet ducts.

    POLYCARBONATE REAR HATCH

    Another piece I had purchased way back in January of 2015 that never made its way onto DangerZone was a pre-formed and pre-cut polycarbonate rear hatch from Five Star Bodies. This 1/8" thick, pre-trimmed, formed rear plastic glass was to replace the 46 pound OEM glass rear hatch section.



    Removing weight was the primary goal, but with our new 2016 minimum weight numbers going up now this might not make as much sense.



    Of course we did this before the new weight numbers came out, heh. Oh well, being able to move weight from up HIGH (stock glass) to down LOW (ballast) is always a good thing. I'm eyeing that 80 pound hood as well.



    Once the glass was removed from the factory hinge at the back of the B-pillar factory roof structure, Olof drilled two matching holes in the trimmed-to-fit and pre-bent Plexiglass. Then he built a frame to give it some support at the lower front corners out of thin wall 1/2" tubing. The two Quik-Latches just arrived and those will take the place of the (broken) rear hatch release. Now we can get into the rear area without crawling through the cage and yanking the emergency release cable in the back.

    WINING HARNESS & MAF CONVERSION

    So if you've read this thread before you know we had some trouble with the original 1992 ECM (Engine Control Module, or computer) after the rebuilt motor went in, that caused us to miss our last NASA race of the year - the car wouldn't start reliably. After days of diagnosis and parts chasing we had finally realized it was a bad ECM. Well we cannot find a new 1992 ECM, anywhere on the planet. 1992 Corvettes had a "one year" ECM - 93 was different, 94-95 was different again, and 96 was also unique. There are no 1993 ECMs left either, but back in October we found plenty of 94-95 Corvette computers available, both new and rebuilt, and our tuner said the later computers were easier to tune for track use. So the quest to convert this to a 1994-95 EFI harness was underway in October.


    Instead of trolling junkyards for 20+ year old Corvette engine harnesses, which will bound to have some cracks and wiring breaks, we had a new one built using our 1992 OEM wiring harness for layout. We found several breaks in the existing 1992 harness already - which makes for nightmares when diagnosing EFI issues and the way this one will be built will be the perfect OEM replacement - 100% stock in form and function, just not with 25 year old wiring and broken connectors.


    We had to find 1994-95 MAF, intake tube and other small parts to convert this car fully

    We are trying out a new harness supplier, but they assured us it will be identical to an OEM 1995 Corvette harness and plug in, no issues. As long as it mimics the OEM harness and we use an OEM 1994 or 1995 ECM, this should be a zero-point change, as all 1992-1996 LT1 Corvettes are listed on the same line.



    The harness took a few hours to label the connectors (any emissions or cruise control related connectors will be removed, which again, is legal for TT-Letter) and disconnect everything all the way to the ECM and firewall, and even some bits that went down to the ZF 6-speed. We should hopefully see the replacement harness by the end of this week, which will give us just one week to get the engine dyno-tuned again before an upcoming track test at MSR-C on January 16th.



    That's what the engine bay looks like now, above left. The 1992 harness was been shipped off weeks ago (they have to re-use some connectors, which are not being made any longer) and it will look like the 1994-95 engine bay soon (above right). We already have an OEM replacement MAF and intake tubes, shown there. Luckily this 1994-95 stuff is available and not costly (new Delphi MAF was about $100).

    I will show this all wrapped up and hopefully running well again in my next post.

    WHAT'S NEXT?

    Since this was only a partial update I'll have another that will show the completion of all of the above work (hopefully) posted after the next NASA event. That assumes a lot of things happen in a timely fashion over the next 2 weeks and that our test at an SCCA Club Trials event goes off without a hitch.






    Sadly these were the only two tracks we ran the Corvette at last year, but we'll be hitting them back-to-back weekends in January 2016. This time the car will have a newly rebuilt engine, no fluid leaks, better engine and brake cooling, and hopefully some reliability. There were major issues with the C4 at both tracks in 2015 - a leaking rear seal at MSR-H kept us to 1-2 lap stints before we were black flagged, and oil smoke from a worn out engine kept getting the car black flagged at MSR-C in one lap or less. No more of that nonsense!

    We ran a 1:43.7 lap at MSR-H in 2015 (still the TTC track record) and hope to better that by a good margin this year. We never got an official time in TT at the MSR-C event but, but I did run a 1:25.0 in the TT Warm-up session, which was my only complete lap of the weekend in that car. That was 2 seconds faster than the old TTC record at the time, but another TTC car reset the record on Sunday to a 1:24.424 (Mark Schnoerr's E36 M3). Hopefully #DangerZone can go quicker than those times at both tracks? The SCCA Club Trials event doesn't really have "classes", per se, but it will be a good practice for when NASA comes back to this track in March 12-13, 2016.



    That's all we have planned so far for the 2016 season - after the January SCCA and NASA track events we will see how we stack up in class for the year and go forward from there, either with refinement or possibly even changes to move to a new class (if the added TTC weight is a big hindrance). We will also have Amy's red 2001 BMW 330Ci at these two events, which is the new #JackDaniels TTD classed E46. For the C4 we have to have the rebuilt harness installed with a 1994-95 ECM (of course now there are none to be had, ugh!), the engine re-tuned to work with the 94-95 MAF, the Plexiglass rear hatch painted and latched, the front brake ducting wrapped up, and maybe some other small changes if there is time. Check back in a few weeks to see if some what happens...

    Cheers,

    Leave a comment:


  • Fair!
    replied
    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    Project Update for January 5th, 2015: Its been a couple of months since I touched base on the progress of Project #DangerZone, our 1992 Corvette race car, and a lot of little things have happened - both to the car and to the NASA base classing rules for 1992-96 Corvettes. We've made some updates to the C4 to hopefully make it lighter (pre-ballast), run cooler, and more importantly - be more reliable once it returns to track use later this month. The C4 is also looking like my only primary race car for 2016, so we're getting a bit more serious with prep on this car and might add a few other racing groups to run the car in. There's only 3 weeks until the next NASA race we want to make in this car (NASA @ MSR-Houston event Jan 23-24) plus a test day at MSR-Cresson the weekend before (Jan 16th at MSR-C). I'm only going to cover the work completed up until now then catch up on the finish work before these two race dates in the next update.

    NASA RULES CHANGES

    As some of you might know we've started a BMW E46 330Ci build for NASA TTD class. That project has gobbled up some time and we switched chassis before we even began major race prep on the first car (325iC), which slowed us down a bit, but it was the right move going from the 325 to a 330 (the latter of which was classed better and makes a lot more power). You can read up on that car here, which we've named Project #JackDaniels. I explain the name in that thread.

    Normally in December of each year, NASA will release an updated rule set for Performance Touring, Super Touring, and Time Trial classes - all 3 of these groups use essentially the same set of rules. PTB-PTF wheel to wheel classes equate to TTB-TTF and ST1/2/3/U equate to TT1/2/3/U. Sometimes the rules aren't published until after the first of the year but this time the 2016 NASA TT rules came out on time, with nearly 8 weeks before our January 2016 event.



    The C4 listings above are what we built this car around, and those haven't changed in many years (we know because we have been eyeing this car for TTC for 4+ years). But due to how well Dave Schotz did at NASA Nationals West in his PTC/TTC C4, and how much we riled up a few folks with our forum build thread (even though it really only completed one race weekend), we were expecting either a points penalty (*), class change (TTB?) and/or minimum weight change (increase) to these C4 base classes. So here are the 2016 changes...



    All changes from the previous edition of the rules this year are shown in blue. As you can see the minimum weights for 3 of the C4 models were changed, all higher, including our 1992 LT1 base model. We have to add 57 pounds to our weight or else take points for weight loss, which gets expensive. As you may know we had maxed out this build on points from the beginning. Somehow I never really covered that in this thread...

    This post on our E46 TTD build thread explained in great detail how we came up with the classing, tire size/compound, chose modifiers and found rules exploits for both the TTD car and this TTC car. I won't repeat what I wrote there in total but if you care to learn some of our secrets, please go here and check it out.

    Here is a quick summary of our TTC class build for this 1992 Corvette, based on the old 2015 rules. After we saw the base classing (TTC*) and weights we looked at the Power-to-Weight (P-to-W) ratio assigned to the class (12:1). The * cost us 7 of the 19 class points we had to spend, so we have 12 to play with to stay in TTC. Then we looked at the base tire assigned to the class (255mm). Going up in size costs points, down in sizes nets points back. From there we looked for modifiers to the P-to-W ratio... and found a big bonus (+0.8 ) if we ran a small 245mm or smaller DOT tire (see Appendix B in the rules). 1 point was also gained back because that's 10mm below the TTC class starting tire size of 255mm.

    This modifier effectively moved the P-to-W from 12.0:1 to 11.2:1. Luckily the stock LT1 motor could still hit that revised P-to-W limit without any power modifications. This meant we didn't have to burn class points on exhaust or headers or camshaft swaps or intake mods to max out P-to-W. We spent ALL of our remaining points on suspension changes (springs at +3 points) and tire compound (R7, +10 points), plus our point gained back for 245s (-1) and it worked out to the 12 point mod limit for TTC with maxed out power limit.

    Let's show those P-to-W calcs "the NASA way" for our TTC Corvette:
    • Weight must be at or above the listed minimum classing weight of 3203 pounds, from the 2015 rules
    • That 3203 number is also just above the minimum "competition weight" modifier numbers, which start at 3200 pounds
    • We chose a 245mm width DOT legal tire (+0.8 P-to-W bonus)
    • The stock engine made 284 whp peak (highest of 3 pulls)
    • 3203 lbs / 284 whp = 11.28:1 (P-to-W) + 0.8 for (245 tire modifier) = 12.08:1


    TTC Class "minimum" adjusted P-to-W is 12.0:1, which this car is just a hair over. That's what you want to do - aim for the P-to-W limit and find any modifiers you can to help that ratio along the way. Avoid modifiers that hurt, then use your points to run the best tire compound/width and fix any suspension issues, and add aero if you have any points left. Again, this is more detailed in the E46 TTD thread, linked above.

    So that was our TTC strategy for this C4. Now we have to recalculate for the higher 2016 minimum weight bumps, which honestly aren't that bad and are not unexpected. I have to agree with these changes, even if I don't like them. This will mean we have to run even more ballast on the same 245mm tires, which worries me. We haven't dyno'd the fresh LT1 motor but I'm also worried it might make too much power, even at this higher weight (and with the 11.2:1 P-to-W ratio we can now make 291 whp). Even with it only running briefly due to the ECM issues it felt STRONG - and yes, it was a 100% legal engine rebuild. We shall see soon enough.

    Sadly our E46 TTD build gained a 7 point penalty with the 2016 rules, which I'm not at all happy about. Really borks the planned build. So of the very few changes made in 2016 both of our TT-Letter builds were impacted. I'm just that lucky, I guess.

    BRAKE COOLING MODS

    Meanwhile in last two months, before we got the new 2016 rules, we have been working on some reliability mods to the C4. Of the 2 race weekends we ran this car I never managed to make more than 2 laps in a row. So the stock Z51 brakes haven't been pushed hard enough to overheat, but I'm worried they will be taxed once we get the car on track without a leaking or smoking engine. Why worry? Well because I'm a Left Foot Brake fanatic (learned in my autocross background) and I tend to abuse the crap out of brakes.



    With an R7 tire compound I don't have to get my best laps in on lap 1 or 2 like we did on the A7s in TT3 last year, so yea... brakes might become an issue. So one day when we had the C4 up in the air for harness removal (see below), I asked Olof to pull apart the front brakes on one corner for a better look. We had built brake backing plates with cooling ducts for a C4 before and he kept the templates we used that time, so this shouldn't be a whole lot of work.



    After he made a flat plate that fit around the hub we discussed where to route the hoses, what sizes to go with, and what shape for the duct at the backing plate. We decided to use 3" oval tube for the inlet, aimed at the hub and inside the rotor face. He built these 2-piece backing plates below.



    With only a 13" rotor there wasn't room for a 4" duct, and with the track performance of this car a 3" cooling hose should be enough. Now there's also lower piece to this backing plate added to help seal off the hub section so that the incoming air goes where we want it to. It also allows for a bit of a heat shield from a ball joint that is very near the inside rotor face, shown below.



    The spacing from the backing plate to the rotor face (shown in the picture above right) is what we try to stick with, which allows a decent seal to the incoming air but shouldn't ever rub. The goal is to turn the rotor into a centrifugal air pump, with the incoming air forced into the hub area inside the rotor and the curved vanes of the rotor pulling air through the rotor and out radially. This can increase effective braking during a session considerably, as well as extend brake pad and rotor life substantially.



    As you can see above left, even the oval shaped 3" duct doesn't put the incoming air completely inside the rotor face, but its as close as we can get without nearly flattening the oval shape. Another thing that we did while the hubs were off was install extended length 3.25" ARP wheel studs. We couldn't find a bullet nosed ARP stud any longer than the itty-bitty stock studs, so we'll just have to start each lug by hand with this fully threaded ARP (it's not like we're doing fast pit stops). The reason why I wanted long wheel studs will make itself known in my next post.

    While doing the front stud install we would normally swap in new hubs at the same time, for other cars. But for the C4 we kept the original front hubs - they were still low mileage, still felt tight, and the aftermarket options are total CRAP for this chassis. The only good aftermarket replacement hub for this car worth using is a racing hub made by HPE that costs $699 per corner, and I'm not sure if their solution is even TTC legal, so we'll keep the stockers on there for as long as we can. Brake cooling aimed at the hubs tends to extend their lifespan quite a bit on track, too.



    Backing plates are only 1/3rd of the brake cooling solution - you also need INLET ducting at the front of the car and then brake hoses to join them. After looking at the front end of this C4 I wanted Olof to "keep it simple". Why? Well we're likely replacing the bumper cover later in the 2016 season since the stock cover is pretty beat up. We had discussed about re-purposing the turn signals, adding NACA ducts in the old headlight doors, or even NACA ducts under the front bumper... but I wanted to keep it very simple. "Just make a 3 inch round tube and a flange", which is exactly what he did.



    Remember - this might not be the permanent inlet duct solution, just a quick one for now. The inlet ducts were relatively easy to make and I had a specific place I wanted them placed. The front of the C4 has a LOT of "front overhang" (see above) where the nose pokes out about a foot in front of the factory front lower air dam (the air dam feeds air to the radiator). All of the radiator cooling is drawn in from under the giant overhang, but there is still some dead space on both sides of the radiator inlet that goes unused...

    continued below

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  • Fair!
    replied
    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above

    The Optispark previously used in this C4 was an aftermarket $500 MSD unit that had less than 3 hours of use on it, so I doubted it could be bad. Maybe a ground wire was missed, or a wire cracked during the install (from age) on the factory harness? Ryan and Brad broke out the factory 1992 Corvette manuals and went through the Ignition Troubleshooting Flow Chart, step by step. Everything they checked worked, we just didn't have spark. Voltages were checked in the harness and into the Opti at several locations. The coil was swapped out for an MSD LT1 unit we had in the shop. No help.

    Finally we broke down and ordered a stock replacement $150 Optispark unit from O'Reilys, which showed up 10 minutes later. It was 3 pm the day before our scheduled dyno day and track test, so it was worth the peace of mind.


    This small victory was short lived - the problem never really was in the Optispark

    We plugged the new unit into the engine harness, put the coil lead near the cylinder head, and spun the drive on the Opti... pop-pop-pop. We had spark, so it was proven to work. So out came the nearly brand new MSD Optispark unit, which meant the water pump we had just installed had to come back off. Order more gaskets while that's being swapped in. While the MSD Opti it was off the car they did the same "off the car" test and... damn it, the MSD unit worked like this, too. So I had to make the call... put the problematic MSD unit back on or have them install the brand new OEM replacement Opti? I told them go with the brand new unit.

    By this point we had called and spoken to several LT1 experts and got suggestions from "bad ground", "bad ignition module", "bad ECM" and of course "Its the Opti!" It is almost always the Opti, but I doubted that more and more as we tested the old MSD unit off the car and it came back as good.


    Another short lived victory - it started with the new Opti, but ran poorly

    After a long day of troubleshooting the engine and with the new Opti installed, the engine fired up and ran briefly with the water pump off, so that was good. Then the water pump and coolant hoses had to go back on, the coolant get filled (with distilled water + Redline water wetter) and burped again, and the front of the engine went back together - drive belt, intake tube, etc.



    What should have taken an hour to wrap up that Thursday morning ended up taking all damned day. The engine was finally started, it ran (poorly), the coolant system burped, temps checked out and loaded into the trailer for a dyno test the next morning. It was 7 pm and everyone was glad to go home.



    Still, it just wasn't running that smoothly. The engine was idling way too high, way up at 2000 rpms, and it had a throttle tip in stumble. Our LT1-expert Ed stopped by and got the set-screw on the throttle blade set to turn ever so slightly and now it would idle at 1600 rpms, but it wouldn't go lower. Hmm. Also, after the engine warmed up, it wouldn't start again easily. It would crank, but wouldn't fire. Something still wasn't right. After 10-15 minutes of cooling down (it barely got up to operating temps) it would fire up, but once it was warm again and we shut it off, then tried to restart it - nothing. Just cranked, no fire. What is going on here? We scoured the car looking for other issues - grounds, broken wires, etc.

    The guys at True Street had been ready for us to come by mid-day Friday for a dyno check and re-tune, but with the Optispark + other issues, we were delayed by several hours and missed their deadline. I called them at 4 pm and told them we were going to miss that window. Luckily they were hosting a big "dyno day" setup the next morning, so I planned to get there early and be first in line.... then head to ECR for a member day track test right after that.

    Dyno Check at True Street, Saturday October 10, 2015

    Loading the car into the trailer with a triple disc clutch is a PITA, but we hadn't stopped long enough to make front (or rear) tow hooks for this car. So when we got to True Street Motorsports at 8 am Saturday morning, an hour before they opened, Amy and I just rolled the car out of the trailer. Then I tried to start it...



    NOPE. It cranked like a champ, but once again the coil wasn't firing. It won't start now, even cold. We fought with it for a solid hour, clearing the battery and trying again and again. It got to where the battery was losing voltage, and it still wasn't starting.



    I thought about asking the guys at True Street for a hand, but they were all busy getting their shop cleaned up and ready for 200+ people, who had started arriving in droves. They had a food truck setting up, and cars starting to get dyno'd when we decided to abort the dyno test and load up.

    Missing this open track day at ECR was a huge disappointment, and it put me in a foul mood for the rest of the day. I knew we would have to spend more (unbillable) hours the next week to get the C4 running "right" and starting consistently before going to NASA @ TWS the following weekend, without any test time on track. With a new motor, new radiator, and new crankcase breather. Testing this many new things during a competition weekend sounded like a bad idea, and it is.

    More Testing At The Shop + True Street

    Monday morning we unloaded the Corvette at Vorshlag again and Ryan and Brad spent most of the day tracing circuits and testing everything, wiggling the harness, and looking up issues with these cars. More and more evidence started to point to a bad ECM - the 25 year old engine computer might be at fault. My ops manager Steve started chasing down replacement 92 Corvette ECMs and that search went well into Tuesday. He called dozens of wrecking yards and LT1 re-programmers, parts suppliers and GM dealerships across the country. Nothing, nada, zip - no 1992 Corvette ECMs anywhere.

    Just to eliminate any last "part problems" we ordered a new ignition module and replaced it. This was mounted it to the coil/module bracket with proper Heat Sink Compound. Then we spaced the module + coil bracket away from the cylinder head for heat protection from the engine. No change.

    Sometime around mid-day Ryan had done some sleuthing online and found a number of 92 Corvette owners with eerily similar problems. One suggestion was to remove the PROM chip inside the ECM housing and re-seat it. Another said to "whack the ECM a few times, hard!" After doing those two things the car started up again, but still ran a bit rough. More tests were done, but it at least ran. We called True Street, who were backed up with tuning work for 3 weeks... I begged, and they agreed to call me back if they had an opening. As luck would have it they had a last minute cancellation and were able to sneak us in for a dyno check-up. I towed the C4 up there Tuesday after lunch and they got to work.

    After I left, it wouldn't start again. Sean played with things, checked some codes, and late that day they had found a bad TPS sensor. With the TPS unhooked it would start, but you can't drive the car like this. We had replaced the TPS with a new sensor back in February, after I noticed a weird "throttle dead spot" at the January NASA event. Hmm... red flags were going up.



    I spoke with Paul Costas later that night and told him the symptoms we were having, and he related a similar issue he had on his 92 Camaro (which is a GenI TPI V8, but used a similar vintage computer and EFI tech). About a year ago 92 started running poorly and burning up TPS sensors. He talked to an EFI expert familiar with this vintage GM EFI hardware, who said when these ECMs go bad they often lose their reference voltage outputs for 5V circuits like the TPS (Throttle Position Sensor) and IAC (Idle Air Control). He told Paul to test voltage signal at the TPS while driving... and sure enough it spiked way above 5 volts several times, which was what was burning up the sensors.

    And we've just burned up another TPS sensor, and the car had a weird throttle response issue when it would run. And the idle was super high (IAC circuit) at some points. I was more convinced than ever that the ECM was dying and emitting some weird reference voltages. But with no replacement ECM for this car to be found nationwide, the chances of making TWS looked slimmer by the hour.



    I was stewing over this for days and mid-day Wednesday I decided to scrub the TWS event. We had ECM problems and there was no way to fix it in 24 hours we had left. Crap, crap, crap!

    What's Next?

    Long term plans had always been to convert the car to a different ECM and harness from a later 1993-96 Base Trim Level Corvette. There were some EFI changes through the 1992-96 LT1 Corvette era which included:
    • 1992 was the first year of the TL1, speed density air metering, and had the weakest computer with the least number programmable inputs
    • 1993 was still speed density but had a more powerful computer with more inputs to alter
    • 1994-95 was another step up in inputs and computing power with the added change of a move to Mass Air Metering, but still OBD-I. Yet these can be reprogrammed via the OBD-I port, no more E-PROMS.
    • 1996 was another big change, such as the move to OBD-II standards, the ECM had a significantly more powerful processor, a LOT more data channels and programmable inputs, and also no longer relied on an E-PROM to change programming.


    Checking with all of the parts suppliers we use it appears that new AC Delco ECMs for the 1996 Corvette are readily available, and around $200 (with the core charge). The other years are "iffy" or just downright impossible to come up with reliable units. So it looks like I am going to be chasing down a good 1996 LT1 Corvette engine harness, ECM, Mass Air Sensor, and intake tube next. We could not hope to pull this off in the one day we had remaining before TWS, so that event had to be scrubbed.



    We had ordered new R7 Hoosiers, procured a 2nd set of wheels (for the scrub set of tires), event fees were paid, Amy had taken off work, arrangements for the weekend were set, and lots of money thrown at ignition parts that weren't bad - but hey, "that's racing."

    Some of you might question scrubbing this 3 day race weekend - since the engine "technically starts" now. Sure, you can unhook the TPS and it might start, but it cannot be driven like this in anger. It is not reliable, and will almost certain break and/or run poorly once we get this thing on track. If we plug in the TPS it will burn that sensor up in short order.

    I'm not giving up on this car, and it will likely be run in 2016 up until our "Shop Car" LSx BMW is complete. So look for us at NASA events in January and more likely some TEST EVENTS before then, to verify the new engine and ECM changes we have in store. My next update will be after we make the wiring harness and ECM changes.

    Cheers,

    Leave a comment:


  • Fair!
    replied
    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    Project Update for October 16, 2015: Its been another 6+ weeks since my last post, and it has been a roller coaster ride of ups and downs. The rebuilt motor finally showed up on October 6th and was a week long thrash to try to get the car together for a track test October 10th at ECR and a NASA race weekend Oct 16-18 at TWS. We had already missed the September NASA event at MSR-H so we are really pushing to get the car to the last 2015 NASA event in Texas. Unfortunately things did not go to plan and we're scrubbing this race. Let's cover what has been done since my last update to explain...

    Note: After writing this update over the course of 2 weeks of work on the car, I had my thread update completed in a private section of our forum - which we use to compose and edit these mega sized build thread posts. Jason had edited everything the night before I scrubbed the event, and the morning I was going to post this (Wednesday the 14th) our forum crashed and has been down ever since. Its so borked that the server is auto-generating 20,000 error message emails a day, driving me nuts, and I have two teams of tech gurus working on fixing it (we've had that forum operational for 13+ years and its never gone down like this). Luckily I had this post open on a window on my pc, so I could copy the text, but it lost all of the UBB code for formatting, images and links. In a rush to rewrite this post now I won't link all my pics to larger images like I normally do and might miss some links I had in here before.



    You will notice in this series of posts that I'm not sharing any pictures of the inside of the rebuilt motor and censoring some images where those bits are visible. I'm not going to stop sharing pictures in this build thread, as it is still part of showing "what can be done on a budget" and "what race prep we can do" at our shop, but I'm not giving any more ammunition to our competition!

    Rebuilt Motor Arrives

    Let's talk about TT-letter class allowable engine rebuild rules. Here they are:
    Originally posted by NASA TT Rule 8.3.i.c
    18. Engine rebuild with head shave, block decking and 0.020” overbore provided that compression ratio is not increased by more than 0.5 and displacement is not increased by greater than 1.49%. Forged pistons and internals are legal; however, they must be of equal or heavier weight than the BTM parts, and points must be assessed for de-stroking, and/or increased displacement and compression ratio if greater than the limits listed above. (Note: 0.020” overbore with OEM rods and overbore pistons will yield an increase in displacement of approximately 1.1% for most engines.) If forged internals used are lighter than the BTM internals, then Dyno Re-classing (Section 8.4) should be used to prevent disqualification.

    19. Engine balancing and blueprinting

    20. Removal of the engine balance shaft and/or balance shaft drive mechanism

    21. Non-BTM valve springs and retainers, piston rings, and rotary apex seals
    My engine builder worked with me at length throughout this build, and sent plenty of images during the rebuild process, but I'm not showing any those here. NOPE.

    This engine is a NASA letter class legal rebuild, with nothing out of the ordinary. I'm not going to get into the specifics of what we had done to this LT1 engine, but I will say that it was a 100% legal rebuild. No grey areas, no loopholes, just a solid TT-letter class legal engine rebuild that will likely pick up zero horsepower, only reliability. This engine would survive the most brutal tear-down protest. It is also very well built, uses all new parts, and was not cheap. The engine builder even made fun of the fact that we were having to use OEM rockers, pushrods, rocker studs, guide plates, etc. "I've never had anyone ask to use the stock stuff before!" We went over the rules with him in detail, and he is a racer himself and understands how important rules legality can be.



    The engine took over 5 months to be rebuilt partly because so many of the 1992 model specific OEM parts were tough to procure (this "GenII" V8 engine family was only used from 1992-96 and the Corvettes used different parts than the Camaros or Impalas of this generation), and there were parts changes for almost every year of this LT1 - we can use any 1992-96 LT1 Corvette engine, but only as a complete assembly - no mixing and matching of parts like camshafts, heads, etc. We stuck with all 1992 stuff, but it wasn't necessarily the best choice.

    There were nationwide searches to find some of the items needed, which took a lot of time. I'm not going to bore you with the trials and tribulations of building a 25 year old motor with many of the OEM parts, but it was a bit of a nightmare. And the engine builder admittedly had some inexcusable delays on his part, but it finally got here as an assembled longblock at the 11th hour, just in time to make the last NASA Texas race of 2015. Yes, this was long after 3 more NASA Texas events passed + NASA Nationals East was missed, which I was none too pleased about. We missed almost the entire NASA race schedule, but we hoped to make the last event here...

    Parts Cleaned, TB Airfoil Removed, New Plug Wires + Wrapped Manifolds

    The longblock was placed on the engine stand mid-day Tuesday October 6th and then the washed and cleaned Moroso oil pan was installed with a new FelPro gasket and some RTV. Then it was onto several other checks, then the intake manifold and valve covers were cleaned up on Wednesday...

    These would be installed after the motor was back in the car, to save time. Some deadlines were looming: be at True Street for dyno checks and possible re-tune that Friday, then out to ECR on Saturday for track testing, then any last minute updates the following Monday-Thursday, then load up and head to TWS for a NASA weekend the next Friday-Sunday. Plus our shop was full of customer cars that all had their own deadlines, many going to the same TWS race weekend.



    While the guys were putting the LT1/ZF6 drivetrain in the car Wednesday morning, I took the intake and valve covers to Friction Circle Fabrication in Lewisville to have these 25 year old parts cleaned in their UltraSonic parts cleaner. These dirty bits were soaked in the 155°F degreaser solution and agitated for 90 minutes, but they came out super clean. In hindsight we should have scraped more of the burned oil residue off the valve covers mechanically before going in the ultrasonic - would have saved a lot of time.



    It is a good feeling to know your new engine isn't going to be filled with trash that fell off of some dirty part you reinstalled. And there was some serious crusty, nasty stuff on the bottom of the valve covers and inside the intake. Old, burned-on oil residue plus liquid oil in the intake - from the massive blow-by - which was being pumped back into the intake via the PCV system.



    When I returned with the cleaned parts, Ryan installed the intake manifold (which was a chore - long story) plus the 25 year old OEM injectors. The stock injectors were cleaned and flow bench tested at InjectorRX in Houston back in August, and as you can see with the test results above, the flow rates were all over the map. Three of the units were also leaking and all of them were clogged before, but after they were (ultra sonic) cleaned and rebuilt they all flowed the same. Good insurance on a set of OEM injectors this old - and yes, we have to use the stock parts here, or take more class points we don't have.



    The aftermarket throttle body airfoil, which we didn't know was installed until someone noticed and pointed it out from one of my build thread pictures earlier this year, was removed when the intake manifold went back on. The one NASA event where we (unknowingly) ran this airfoil on the car and actually got a class win, we had the points for it (+2 points), as we hadn't done spring upgrade yet (+2). These throttle body "air smoothing" airfoils were super common to run "back in the day" on the TPI and LT1 V8s built from 1985-1996, due to the abrupt shape change of the twin throttle body set-ups GM liked to use back then. Nowadays the LS-series GM V8 engines use a single round throttle blade, which feature smooth inlets and MASSIVE throttle blades (and flow) in comparison.



    Anyway, the airfoil is no longer on the car, and is sitting on my desk as a paper weight.


    With the valve covers and intake off, you get a big helping of NOPE

    Before the motor went going into the car we replaced the AutoZone plug wires with some 8mm Taylor wires made for this LT1 Corvette - these are a bit easier to change with the engine out of the car. The old plug wires were still fairly decent looking, but why chance it when the motor is out? Spark plug wires are "free" per 8.3.I.c.6, for any rules lawyers that are reading, and the costs were around $65. I tend to use Taylor plug wires on everything we build around here. New NGK split electrode spark plugs were also used - we've seen good results from these and they don't have itty-bitty iridium or platinum tips that can fall off.



    The OEM exhaust manifolds were also wrapped with DEI header wrap before going on, to keep a little heat out of the engine bay. As we've done throughout this build, if it has to come off or for some other reason we have to touch a part, we're going to make it better - to the limit of the rules and within sane budgetary constraints. Header wrapping the manifolds is legal per NASA TT rule 8.3.I.c.23. Ryan used an old hot rodder trick to wrap these manifolds - he pre-soaked the DEI wrap in water, to make the material more pliable during installation. It was wrapped tightly around each tube tightly then secured with safety wire at the ends. The water boils off quickly during start-up, if the wrap hasn't completely air dried by then.

    Drivetrain Installed + Oil Catch Can/Breather Install

    The re-installation of the engine is pretty boring work, but it does eat up time. And like everything else, doing this work on a Corvette is more cumbersome than most cars. The ZF6 speed was pressure washed and cleaned up (previously covered in oil from the old RMS leak) before it was bolted to the motor. Everything we touch on a race car goes on clean, even old OEM parts. Dirty parts help hide leaks, cracks and other issues.



    Assembling the triple disc clutch to the flywheel, stabbing the transmission and hydraulic TOB, and getting everything into the car was handled by Ryan and Brad. It takes more time to line up the clutch plates and get all 6 pieces lined up together, but this is not hard for our crew. A metal clutch alignment tool is a must for these multi-disc clutches, by the way - we use an old T56 input shaft.



    After the drivetrain is in place, the big aluminum C-channel that connects the diff to the transmission goes in (which also functions as the transmission mount, just like on a Miata), as well as the stock aluminum driveshaft. Then the OEM exhaust system goes in, the stock shifter is installed, various wiring harness plugs are attached, etc. No pics of that as Brad was helping and I was across town. This car still has the original OEM mufflers and catalysts, which we visually inspected very closely before the motor went in - the catalyst matrix is still intact after all these years, somehow. Changing the manifolds, cats, mufflers or even the tail pipes costs points in TT-letter classes, so it all has to stay bone stock.



    After the engine was in place, we did one more (zero points) upgrade I had planned on for a while, and one we do in a lot of customer's race cars (see above) - add an oil catch-can/crankcase breather. This is something smart to add to any car that sees track time or extended RPM use. The way we plumb these, and how we specify the catch can itself, depends on if its an emissions legal street car (above right) or a track-only race car (above left). A street car isn't supposed to have an open vent for crankcase fuel/oil vapors to get out to the atmosphere, so street driven cars are plumbed with a PCV system to pull excess crankcase vapors out during deceleration and route them back into the intake manifold, to burn them in the engine. Liquid oil in the crankcase vapors is trapped within media inside the catch can, which can collect in the can and be drained out after track days. On a race car you don't have to do with a PCV system - and you don't want to.


    This is how much smoke was coming out before the engine rebuild... that's all blow-by

    One of the main problems we had with the LT1 motor in the Corvette earlier this year was tons of blow-by. Combustion by-products getting past the piston rings and valve guides/seals then pushed into the crankcase. This was only realized after the leaking oil pan gasket and rear main seal were fixed before our second 2015 NASA event in this car. The blow-by was from worn out rings, three valve guides that had lots of play, and valve seals that had crumbled over two and a half decades. It was smoking so badly we couldn't make one lap without being black flagged.


    This is the Peterson 08-400 catch can / breather tank we used

    Since I didn't want to take any chances after having "that smoking Corvette" for two NASA race weekends this year, I ponied up for a Peterson Oil Catch Can / Breather a few weeks earlier. It has two -12 AN fittings for inlet, a -6 for a drain (which comes plugged), and the built in breather in the cap. Even comes with a nice mounting clamp. So when the motor was back in the engine bay Ryan and Brad mounted the breather can on the firewall, then plumbed some -10AN bulkhead fittings to both valve covers (because that's what fit the OEM hole on the passenger valve cover).



    One fitting went in the factory PCV suction line on the passenger valve cover but the driver's side cover had to be drilled. We have removed the PCV valve and function completely. These factory LT1 "center bolt "valve covers are magnesium and tricky to work with, but they were drilled handled properly and plumbed with -12 sized push-lock 300 psi hose and -12 AN fittings into the Peterson tank.



    Now both valve covers vent will excess crankcase pressure to this oil catch can, without the need for a vacuum source to "pull" the vapors out. This Peterson catch can has an integral breather in the lid, which is what makes it not street legal. We have completely done away with the PCV system, so now it is less troublesome and won't allow oil and/or unburnt fuel vapors to be returned to the intake track to be burned - which can cause detonation. And if you get a lot of blow-by it won't send liquid oil back into the intake, which is really bad.

    First Fire + Weird Ignition System Issues?

    After the breather tank was plumbed, all of the engine fluids were topped off and some Royal Purple break in additive (zinc) was added to the 10W40 Mobil1 synthetic oil we used for initial break in (normally I like to run 15W50 in race cars). The ignition coil and the fuel pump relay were disconnected, then the engine cranked for 10 seconds, and it made 20+ psi of oil pressure almost immediately. After that the coil and fuel pump were hooked back up, the fuel pump was triggered a few times (key on/off... on/off.... on/off) to prime the fuel pressure in the lines and fuel rails, and then it was cranked. And cranked. And nothing. No start.



    Then began a full day chasing the starting problems. First we assumed the obvious: it was Optispark related. This is the name for the system GM tried (and failed) at making a better distributor with in the GenII V8s, with a weird unit is driven off the timing gear at the front of the motor. This is widely known as a problematic system. The GenIIs camshaft drives the water pump, also strange, which feeds the motor with coolant in the reverse order of any other motor on the planet. The water pump is right in front of the Optispark, and if any coolant/water gets in the Opti, it usually dies. The LT1's two main bad ideas were the Optispark and reverse flow cooling - they were both abandoned in the next generation engines by GM (GenIII LS1).


    Checking fuel pressure, computer issues, wiring harness breaks at Vorshlag (left) and True Street (right)

    The other issue we kept running into was thought to be VATS related, or Vehicle Anti Theft System. There's a chip in the ignition key that tells the computer "Hey, I'm legit!". Without that handshake the fuel pump won't fire. It intermittently worked, so we have to disconnect the battery to clear it up. Something I thought was removed when True Street tuned the car, but the SECURITY light kept flashing. The VATS on my 1999 GMC truck was doing the same random faults a few months ago and Sean from True Street plugged in and turned that mess off, too. GM "VATS" is pretty much a "leave me stranded in my own car" system.

    continued below

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above

    Engine Bay Power Wash + Seat Swap + Firewall Re-seal



    Having the drivetrain out sure makes for a perfect time to clean two+ decades of crud out of an engine bay. This one had it all - oil, dirt, funk, and grease. Brad rolled the car out back and fired up the pressure washer in 105°F heat and got it blasted clean under there.



    Once inside I used my "WD40 all the things" trick to shine up the old painted surfaces and rubber. Let that soak then wiped it down.



    After the cage tube removal mess we cleaned the glass inside and out with Windex and newsprint, to polish the glass. First time I've been able to see out of the glass in all directions without looking through some film of decades-old funk.



    Today Olof installed the new Cobra seat (the red one went away) and then re-sealed the firewall. There is an aluminum panel where the old factory blower motor/heater core box was in the engine bay, and it leaked a bit of oil into the passenger foot well when the motor smokified. That's finally water tight and should be leak free.

    Now we just need a motor...

    Aluminum Griffin Radiator Upgrade

    One of the things I had hoped to do at VIR was take a lot of laps. I have never driven that track and it has a LOT of turns, so I was hoping to make every session from Friday-Sunday, to learn the line and hopefully put in a good time. I was going to take 2 or 3 sets of tires on 2 sets of wheels, too.

    Originally posted by 2015 NASA TT rules
    8.3.I.c.3) Radiator upgrade/shrouding/fascia modification (drilled or cut holes/slots) that only provides increased airflow to the radiator or oil/transmission coolers (without aerodynamic or engine air intake improvement), and/or radiator core support modification/replacement
    To ensure that the car ran smoothly for longer stints on track at VIR, I wanted to upgrade the radiator. This is FREE in TT-letter class, by the way, for all of you rules Nazis looking at this build (see the "No Points Mod" rule above, which is from page 35 of the 2015 NASA TT rules).

    The stock radiator is already pretty sketchy design, with a tiny aluminum core and glued plastic end tanks. They fail over time at the tank to core junction. This looks like the original piece, too. So I looked at direct fit C4 radiators that were all aluminum and beefed up in size. $545 for one, $625 for another, and all of them would take 6-8 weeks to be built. Nope!



    The OEM radiator is bundled with the A/C condenser (already removed) in this fiberglass, factory duct box. It has no filler neck, as the car has a remote coolant reservoir tank higher in the engine bay. The two fans and shroud look sufficient, and don't do anything at speed anyway. I measured the radiator core size and did some searches...


    We used the generic Griffin aluminum radiator for a mockup in the 69 Camaro (left), which fit that frame spacing well

    Summit Racing catalog has 2,312 different aluminum radiator listings just from Griffin. So I picked a NASCAR style Griffin radiator of the same basic height and width, with the same inlet/outlet layout, but with a massive 3" thick dual core. This was a $175 retail part, now we just had to modify it to fit this car...



    Olof then modified the "generic" radiator to fit inside the C4 shroud and frame layout. The lower radiator hose was angled, so that was cut off and the hole plugged. It needed to move upwards a few inches to clear the front cross beam (see below), so he drilled a new hole and moved it there. Then he modified the fiberglass radiator shroud/housing/mount to clear the inlet on the top left corner. The radiator neck was cut off and capped, then a matching "steam line" was added. This was done with a weld bung and re-using the fitting that came with the Griffin, which was threaded into the water neck for the overflow port.



    It worked out great and took a total of 4.05 hours in total for Olof to: remove the OEM radiator assembly, modify the radiator (cutting and TIG welding), pressure test the modified Griffin unit, modify the brackets/mounts inside the fiberglass shroud, and reinstall everything. In the end we got a LARGER capacity Griffin radiator that fits better and is bigger than anything we could have bought that was a direct "bolt in" for the old C4.



    During that 4 hours of work Olof also made an aluminum cover for the gaping hole in the side of the fiberglass box where the A/C bits passed through (visible above left). The new radiator was bigger in every dimension just enough so that it barely fit in the fiberglass enclosure, and there wasn't even room for rivets to hold this panel on - so it was bonded with epoxy and held in place while it dried with the green tape. There were also weather-strip seals added next to the new radiator to better seal it to the inlet/outlet sections of the fiberglass duct - that should be better than the factory airflow management in the radiator box.

    We're really ready for the motor....

    What's Next?

    I just heard back from my engine builder minutes ago, and he says the last "hard to find OEM LT1 engine parts" are finally there. He's supposed to be wrapping up the motor this weekend, then bring it personally to our shop since its so late (no time for pallet shipment). So I'm hoping he's right, and we might, just might, get this car together in time to make VIR in 2 weeks. They need my entry for TTC to "make a class" at Nationals, so others are counting on us to be there, too.

    We had a lot of other plans we would have implemented if this car was put together 2-3 months ago, like we had hoped for. Things that are small incremental improvements in weight balance, airflow, safety, etc. But with virtually no time left to test even if the motor showed up tomorrow we're holding off on more changes to the car. Too many changes means too many risks of something done that fails - and I cannot afford for any failure if we make it to VIR in 2 weeks. I need an uneventful weekend with lots of track time, some good lap times, and no trivial protests.

    Now we just need a motor...

    More soon,
    Last edited by Fair!; 08-21-2015, 05:45 PM.

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    Project Update for August 21st, 2015: Its been almost 3 months without an update, and while we have knocked out a few things on the C4, mostly we have just been waiting for the rebuilt motor to arrive. We're less than 2 weeks from NASA Nationals East and I had hoped by now to have the motor in, a few race weekends of tuning under our belts, and ready to go to VIR "fangs out". But a big delay on the motor has crushed our hopes and dreams a bit, heh. Read below to find out where we are on this project.



    But first, in celebration of Grassroots Motorsports magazine's annual "Wear Your Helmet To Work Day" (Aug 21, 2015), I give you our submission we took this morning at Vorshlag. This shows almost everyone here "working" on the 69 Camaro Pro Touring / Track Car we're building for a customer (latest update here). That was fun and GRM shared our picture at the top of their page of submissions on Facebook. Installing an intake manifold on the roof like a pro? I think we nailed it.

    The Best Laid Plans...

    So back in early May I had hoped for a quick 2-4 week turn around on the very basic rebuild on the 24 year old LT1 motor. Paid up front to help speed things along at the machine shop, too. I really wanted to make the June NASA event at Hallett, because if I could have made that event (and scored points both days) we could have salvaged a chance at winning TTC in the Texas region season points battle. We only get 4 "drops" for the year in region, and with the issues we had at MSR-Cresson in March I didn't get any points either day, so that's 2 drops. Then we missed the "last ever" NASA event at TWS in April (we ran the TT3 Mustang for one last time), so that's 2 more TTC drops. Making Hallett would keep us in the points...



    Nope, that deadline came and went. Its been 14 weeks since the motor shipped out to the machine shop, but I keep hearing "pretty soon". Pretty disappointed, and if the motor doesn't arrive in the next handful of days we miss NASA Nationals East (13 days from today). We are moving forward with every hope that the motor shows up, then we can thrash to get the drivetrain reinstalled, get the dyno tune re-checked, install the new Peterson oil catch can (below), then rush out to ECR or another local track for some shake down testing. If it looks good there, then we'll pack up and tow 17 hours to VIR for NASA Nationals East September 4-6, 2015.



    But seeing that we would have to leave in less than 13 days, and I have no motor, I kind of doubt we will make it. Some valuable lessons learned, mostly "take your motor out the day after it breaks" and "use a local engine builder" who is close enough to knock on their door. Daily. Oh well, fingers still crossed. Let's go ahead and cover the work we've done in the past 3 months to this car. Even if the motor returns after Nationals is over, we will still try to make the 2 remaining NASA Texas events for 2015, just to see how it does in TTC before the chassis is re-classed in 2016 (likely to TTB or even TT1/2/3).



    Did want to give a shout out and congrats to Dave Schotz. He took his TTC C4 (built at the same time as our's) to the 2015 NASA Nationals West a few weeks ago and won both PTC ant TTC in his Corvette. He also took the wins in PTC and TTB in his 4th gen Firebird. That's 4 championships in one weekend! Way to go Dave.



    The fact that he won TTC/PTC in a C4 pretty much guarantees that the car will be re-classed next year. So that's not good news for us if we miss NASA East this year. We had one shot...

    Old Shocks Rebuilt and Reinstalled

    If you couldn't tell from my last post where I discussed the "the 5 Point Mystery Internet Protest", I didn't agree with many of the items that were ruled against this car - ruled upon sight unseen, after being protested by a competitor with their name withheld. Oh well, now we all know what to expect when you race in the same class as the _____. (you can fill in the blank)



    We got to spend $450 getting the 24 year old factory Delco-Bilsteins rebuilt by Bilstein-USA. Since we paid for a rush it only took 5 weeks to get them back, hoping that the motor would arrive in that time. Money well spent - these sat around for only 2 more months before we even installed them.


    Biggest difference in the OEM vs OEM replacement Bilstein dampers sets? Blue vs Black dust boots. #CheaterShocks

    We made sure to get documentation from Bilstein, showing that they only replaced the seals and wear items. The original shocks' shims and pistons were left alone. But who cares? Nobody believes anything they read on the internet anymore. These pictures are probably only good for use against me in a future internet protest, hehe.



    Olof swapped out the "new" $85 Bilsteins replacements for the $450 rebuilt 24 year old Bilsteins in 1.27 hours of non-billable time. They look identical to each other, but we didn't bother to dyno both sets to prove how equally pitiful the two sets felt. I'm sure they are just as floaty as the "new" set was.

    8.5 BTM (Base Trim Model) Definition, Updating and Backdating Rules
    For the purposes of NASA TT Modification Points assessments, the term BTM will be defined as follows: Any part that is identical in size, shape, and functional characteristics compared to the part that originally came on the vehicle, from the manufacturer, as a standard feature of the base trim model as it is listed in section 8.2 Base Classifications (factory options and specialty model parts are considered non-BTM) or is listed as a standard replacement part by the manufacturer (OEM).

    Some parts that are produced by aftermarket manufacturers as generic replacement parts may not require a points assessment provided that: they are the same size and shape, and have the same functional characteristics as the BTM part, and that they provide no significant improvement in performance, longevity, or reliability. If it is determined in impound that such a part does not meet the above description, the driver may be disqualified. Consultation with the Regional TT Director prior to competition is advised for any driver using a vehicle with replacement parts that fall under this exception.
    This is sufficiently vague as to mean "we can pick when we want a replacement part to be legal". We learned from this ruling and the precedent set that: unless you are using the original, as-delivered factory base trim level shocks on your TT letter car, you should just take 2 points for whatever shocks you have installed. There is no "OEM equivalent" for these mysterious and mythical parts called "dampers". You were warned.

    Remove Cage Tubes

    Speaking of wasted hours, Olof spent another 2.4 hours taking these roll cage bars out. Yay.....



    Again, I completely disagree that these two optional bars forward to the firewall aren't 100% legal (again, without taking points we didn't have). They were installed as no-points tubes to the letter of the rules, but the "unwritten" wording is what got us. They weren't below the top of the tire, which is true - even if that phrase is nowhere in the NASA rule book.



    These two optional bars connecting the door bars to the frame on the passenger side weren't legal without taking points. I still think its silly to encourage asymmetrically safe cages, but we pulled those two bars out.



    Once the 4 tubes were cut out the flapper wheel on the electric grinder was used to get the stubs of tubes smoothed flat. It took time and made a huge mess, but there's now no sharp edges to catch a driving suit or cut your skin, if snagged. And more importantly, there's no nit-picky visible items to protest. #CheaterCage



    Cutting and grinding the cage to get these tubes out made a lot of metal dust, which went everywhere inside the car, so Olof spent another 1.15 hours cleaning out the entire interior. With some oil that was spilled in the floor on the passenger side (when "Old Smokey" was giving its last death throws at the NASA MSR-C event), and piles of metal dust, it made a real mess. But he got it cleaned out and ready for the replacement Cobra Suzuka GT seat - which is here and going in later today.

    continued below
    Last edited by Fair!; 08-27-2015, 10:39 AM.

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above



    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.


    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.



    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.



    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,
    Last edited by Fair!; 08-05-2015, 06:18 PM.

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  • Fair!
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    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.



    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.



    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.


    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.



    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.


    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.


    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".


    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.



    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).


    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.


    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
    Last edited by Fair!; 08-05-2015, 06:17 PM.

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued below



    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.



    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.


    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.



    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,
    Last edited by Fair!; 04-23-2015, 04:42 PM.

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  • Fair!
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    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.


    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.



    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.



    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.



    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.



    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.



    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.



    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.



    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).


    My temporary "breather mod" only made matters worse, so I shut it down after less than a 1/2 lap. "....MEH..."



    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.



    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.



    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
    Last edited by Fair!; 04-23-2015, 04:36 PM.

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above



    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.



    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.



    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.


    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.



    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.



    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.



    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.



    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.



    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.



    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).



    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.


    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.



    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.



    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.

    Cheers,

    Leave a comment:


  • Fair!
    replied
    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.



    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.



    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.



    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.



    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.



    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.



    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.



    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.



    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.



    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.



    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
    Last edited by Fair!; 04-23-2015, 08:44 AM.

    Leave a comment:


  • Fair!
    replied
    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.



    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).


    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).



    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.


    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.



    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.

    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,
    Last edited by Fair!; 08-05-2015, 06:08 PM.

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  • Fair!
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    Re: Vorshlag Budget TT Build: Project DANGER ZONE

    continued from above



    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).



    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.



    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.



    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.


    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.

    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.



    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.



    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.


    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


    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.


    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
    Last edited by Fair!; 01-26-2015, 12:32 PM.

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  • Fair!
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    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.



    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.


    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.



    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.



    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.



    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.



    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.



    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.


    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.



    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
    Last edited by Fair!; 01-26-2015, 07:06 PM.

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