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PostPosted: Tue Jan 27, 2015 7:04 am 
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Sorry, I will try to make a better "budget list" in my next post. I ran out of room in this one (3 separate posts nearing 20,000 characters each - which is the limit for many forums), so I just referenced the rough estimate ($5000) on what we've spent on the car and parts + the accounting of 60 hours logged working on this car, to date. And like Jason said, this car came with a lot of replacement OEM and aftermarket parts already on it.

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PostPosted: Tue Jan 27, 2015 8:22 am 
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Fair wrote:

I Need To Apologize for Trash Talking? Really?



Never! Trash talking is what separates us from the animals.

McQueen's line should have been "Racing is life. Anything before or after is just bench racing."

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PostPosted: Fri Jan 30, 2015 9:11 am 
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So.. reckon we will see a ban on C4s in letter class now? or just the elimination of TTC? :wink:
need to get my C3 project back on the front burner

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PostPosted: Fri Jan 30, 2015 11:06 am 
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jvetthead wrote:
So.. reckon we will see a ban on C4s in letter class now? or just the elimination of TTC? :wink:
need to get my C3 project back on the front burner


Don't bother Joe. After Terry and Dave wipe the floor with wins and track records this year I predict all Corvettes will be banned from competition. Followed swiftly by all BMWs and Miatas. I've got big plans for my sons tricycle though!

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PostPosted: Fri Apr 10, 2015 8:53 am 
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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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


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PostPosted: Fri Apr 10, 2015 8:57 am 
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continued from above

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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).

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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.

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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.

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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).

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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.

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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.

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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.

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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

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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.

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YouTube video: https://youtu.be/iG3ZQ7gbFbk
SmugMug video: [url=vorshlag.smugmug.com/TechArticles/This-Week-in-the-Vorshlag-Shop/43681479_FRMZw4#!i=3982293520&k=khqGZf9&lb=1&s=A]LINK[/url]

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).

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That's all I have for this time.

Cheers,

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PostPosted: Thu Apr 23, 2015 1:52 pm 
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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.

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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-Events/NASA-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.

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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.

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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.

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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.

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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.

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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.

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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.

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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!

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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.

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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.

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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.

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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.

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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.

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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).

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

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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.

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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.

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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.

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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!

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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


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PostPosted: Thu Apr 23, 2015 1:54 pm 
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continued below

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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.

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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.

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Left: Saturday TT Results. Right: Sunday TT Results

Official Results: http://timingscoring.drivenasa.com/NASA_Texas_Region/2015%20-%20Official%20Results/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).

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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.

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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.

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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.

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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

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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,

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Terry Fair @ Vorshlag Motorsports


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PostPosted: Thu Apr 23, 2015 4:13 pm 
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I am not privy to your supposed protest, but I can tell you that I (and another competitor) had to cut those very same passenger side NASCAR-bar-to-sill-plate tubes at the Nationals at Mid-Ohio in 2012 when my C5Z06 was in PTA. I did not protest because I was the one that overlooked the rulebook when having the cage built. My intent for those bars on the passenger side was specifically for when I take passengers for rides at Charlotte Motor Speedway and I run through NASCAR T3-4 at 140mph. I cut the bars, kept them, and then had them welded back in when we switched to Super Touring six months later.

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Kevin
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2015 ST2 EC Champ, 2017 TT3 EC Champ
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PostPosted: Tue May 26, 2015 2:46 pm 
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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.

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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

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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.

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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.

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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.

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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.

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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.

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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.

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Yes, this car is still for sale, now at a lower price!


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!

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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 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).

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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.

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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.

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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 says isn't full concept of what the rules makers meant, however, as I'm told after this ruling that it should read as follows:

Quote:
"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".


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

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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).

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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.

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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


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