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Unread 03-25-2016, 08:54 AM
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Join Date: Jul 2004
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Default Re: Vorshlag Budget TT Build: Project DANGER ZONE

continued from above

Saturday morning it was still wet and sprinkling, so I drove the BMW in the TT Warm Up on street tires, with Jon riding shotgun. I had hoped to show him "the line" (this was his first time driving at MSR-C), but anywhere on the 16+ year old, original track surface that was "the line" was polished smooth. Add in the water and it was like driving on ice, so the trick in the rain here is to NOT drive anywhere near the proper driving line. The marbles is where the grip is, strangely enough.



Event Photo Gallery: https://vorshlag.smugmug.com/Racing-...-MSR-C-031216/

After that drift-fest TT warm-up we came in - and realized we forgot to install the AMB transponder on this car. No official time, doh! So that meant that I would be gridding in the next TT session at the back, no matter which car I brought to grid. I ran the red 330 again and got a time good enough for the win for the day, but I was itching to get into the once again TTC classed C4. This would be the first time it has been run in TTC with the fresh motor, on a sticker set of tires, with the upgraded spring rates, and the "rebuilt" OEM shocks. Aka: the most prepped it has ever been for any class.



After lunch the rain finally let up and began to dry, so we unloaded the Corvette. The track surface dried off in TT session 3 and I took the C4 out for the first time on Saturday. We had 6 cars in TTC class so whoever won today could potentially take home 2 Hoosier tires. I was mired in traffic and couldn't get a clear lap, ran a 1:24.X in the session with 2-3 passes per lap, but I at least moved up the grid. The old MSR-C 1.7 CCW track record for TTC was a 1:25.1, and both BJ and I had both beaten that already.



In the final TT session of the day I was trailing BJ Meyer badly in his TTC prepped Mini Cooper S (parked to the left of me in the image above). Supercharged, on coilovers, lots of boost, and driven well at this, his home track. In the final TT session of Saturday I put down a blistering 1:22.206, with only one semi-clear lap for traffic, with a number of small driving mistakes. But BJ put in his personal best of a 1:21.996, taking the win for the day. My time was good enough for 2nd, but I knew I had more in the car - predictive showed some high 1:21's but traffic kept killing my best laps. At least I'd be further up the grid for Day 2!



Jon was in HPDE3/4 and as the track dried up we swapped on the Hoosiers and he was having a blast. I saw the TT "needle go into the vein" for Jon this weekend... he's been cooking up TT builds on paper all week!

Sunday morning was a bit of a mess, and it was my fault. This was the Daylight Savings "leap forward" day, where we lose an hour at 3 am. My smart phone alarm can catch that, of course, but the problem was I set the alarm for... a weekday. So I overslept and made us super late to the track. We rushed to the track from the hotel but I made it in time to get into the 330, throw some fuel in it, and make it to grid with 1 minute to spare. I ran the first TT session in the BMW and again was mired in traffic. Getting a good lap in a gutless car that cannot pass anything is actually pretty difficult. I ran a 1:27.604 in the car Saturday but only managed a 1:27.854 on Sunday in this, the only session I ran the 330. Turned that car over to Jon for the rest of the day and spent the the other trying sessions to chase down that damned Mini in TTC!



In TT session 2 the Corvette was at least gridded 11th out of 39, so there should be a better chance of getting a traffic free lap? Well, not so much. I was on a quick lap and lost track of which car I was in... there's three left handers (T5 - T6 - T7) in the back section of the 1.7 course that I can take with the throttle matted in the TTD BMW, but not in the C4. Well I mis-remembered that, and kept the gas pedal mashed, and put two wheels off at the exit of T7 (Tombstone). And the grass was still wet, so that two off quickly became 4, which turned into a big graceful loop across track and into the grass. Yea, I spun it, which DSQ'd the session. I came back in and tried to get my head on straight.

BJ was checking to see if I was going out in TT session 3, and I told him that I damn sure was. So I got to grid for that session and all 3 of the top TTC cars were lined up pretty closely. BJ's Mini was sitting on a 1:21.8, I was gridded right behind him, with Mark Schnoeer's TTC M3 just behind us both with a 1:24.8 (last year's record setter). I needed to get the lead out and put a clean lap in for the day in the C4. I knew the C4 had enough performance in it to beat the Mini - it had beaten it every time before - but there was the whole driver thing I had to do.

I didn't know how much more the master cylinder had in it, but I was going to push for the win in this session. The first two laps of this session were traffic, and I passed some of the faster cars gridded ahead of me, but BJ was always right there about 30 yards ahead, too. By the start of the fourth hot lap I had passed the cars ahead I needed to, built a gap to BJ's Mini so I wouldn't be running into his mirrors, and got the 245 R7s up to temp. The brakes felt OK so I went for and achieved my best lap of the weekend....


Sunday TT Session 3 in-car video

All weekend I'd been touching 106 mph entering Big Bend and on the next straight reaching 110 before braking into T9. With these short tires, 110 mph is at the top of the rev range for this LT1 engine, so I started using 5th gear right before the start finish, and it gained me 2-3 mph (noted 112-113 mph into T9 on those laps). If you listen carefully in lap 3 in the video above, as I'm exiting the fastest corner of the course (Big Bend) I am running out of revs in 4th gear, so once again I planned to use 5th. I looked and saw that Predictive Timing showed me 1:21.6 right as I go to grab 5th... and CRASH! Synchros balk not once, but TWICE! It finally went into gear as I'm cursing the Germans who built this gear box. Even missing 5th gear twice the AiM logged a 1:21.90 lap time.

Son of a... Hindsight being what it is, I should have left it in 4th, because the 5th gear synchro has been "hit or miss" since we bought this car. Its an EXPENSIVE rebuild on this ZF 6-speed, too. Would it have been enough to get ahead of BJ's 1:21.618 he ran in that session? Who knows. At least I knew I had dipped into the 1:21s, which was a goal all weekend.

To make matters worse, after lap 4 in that stint I lost the brakes almost completely, with a VERY long pedal braking into T9. No brakes and no way to fix it at the track, so I missed the 4th session. Oh well, that 1:21.9 would still feel good for 2nd.



No, it just keeps getting better! The AMB timing loop borked that lap and showed it as a 1:03.786... Of course they had to throw out that bogus time (which was during my best lap of the weekend) and used my next quickest of 1:22.786 from that session (in traffic). Sure, its nearly a second slower than what I really ran, but I get it - timing equipment isn't infallible.



Even with a solid margin for Sunday, and after I told him I was done for the day, BJ still went out again in TT session 4 and dropped to a 1:21.589, resetting the TTC record with a strong number. So once again I was 2nd place in the C4 for the day.



During the weekend I was instructing with 4 different HPDE1 students, and sometimes sprinting to the grid to meet them in time for their sessions after getting out of the two TT cars. The grid was way back on the 1.3 mile course, due to the lack of paved parking area on this wet event site. Instructing was fun but made for a hectic weekend and a lot of running around - I need to get a scooter or small track support vehicle, something to get around the paddock in.



So once again the weekend was a mixed success. Driving two TT cars + instructing + talking to customers at our ever-busy trailer makes for a hectic weekend, but it was also a lot of fun. Jon got a check ride for TT and should have his comp license the next time he shows up to a NASA event. I managed two 1st place finishes in TTD (with only one timed TT session each day in this very under-prepped car) and two 2nd places in TTC. At least we were closer to the class winner in the C4 in this class, and we smashed the old TTC track record by nearly 3 seconds (but BJ reset it 3.5 seconds quicker than last year).



We run the same 245/40/17 Hoosier R7 on both cars, so the C4's old tires become the BMW's new rubber, heh. After switching the tires on the BMW back to the streets we moved the trailer to pavement and loaded the Corvette for the trip home. If there was any brake pedal I'd have run the last session to try to chase BJ Meyer down. After instructing in the 5:20 pm HPDE session, I didn't get out of there until after 6 pm, and that 2 hour tow home made for a another 12 hour day. But compared to my normal 7 day a week work days, this was a breeze!

WHATS NEXT

After seeing results that were quicker on the 245 R7s vs the 345 A6 tires, it looks like we're heading back to TTC for the rest of this season. Jumping 3 classes up with just a tire change was foolish, and the proper path involves spending a lot more money than we have budgeted for this car.



At a smooth track like Cresson I ran a 1:23.7 in January at the SCCA Club Trials on the Big Tires (335F/345R), yet I ran nearly 2 seconds quicker (1:21.90) on the little tires with no other changes in March. Being the "fastest car of the day" in January gave me a false sense of confidence, and over-shadowed how the car felt in bumpy sections of this course. At MSR-H the car was tougher to drive on the Big Tire setup, just due to the rougher track surface. In TT2 there I was 3 seconds slower than my 2015 pace on the narrower TTC tires.

Please don't confuse this handful of "data points" with busted theories that "narrower tires work better" on a road course for any given car. I made some posts on Facebook (#SmallTiresMatter) that were in jest, but several people took them seriously. We've proven the small tire theories wrong, time and time and time again. A lot of folks have a lot of theories on why we were quicker on the narrower tires, but trust me... its just a simple matter of the current shocks not working well with the MUCH higher grip levels the wider tires made.



With the right shock and spring package it would be quicker on the Big Tires. Always. We made big drops in lap times on our TT3 Mustang on each jump up in tire size, going to the same tracks. We went from 265 to 305 tires, 305 to 315, and 315 to 335/345, and each increase in width was a drop of 2-3 seconds per lap. Big Tires Do More Work. You just have to upgrade the rest of the suspension to deal with the higher mechanical grip levels. 25 year old OEM dampers ain't the hot ticket on 345 HoHos!

If we had the points for TTC, I'd still install some adjustable MCS dampers for this car. There are still handling issues on even the smaller tire with the factory shocks, just not as pronounced. We're just "point maxed" for TTC right now and cannot add any more mods. Raising the ride height will reduce the chances of hitting the bump stops on bumpy courses, which it still does on the 245s, so that is planned before the TWS event. Here's our TTC build point budget:

Base classing: TTC*, 3260 pounds
- 7 penalty points for the base class "star"
- 10 points for the Hoosier R7 compound
+ 1 bonus point for running 10mm smaller than TTC base tire of 255mm
- 1 point for cold air mods / vented hood
- 3 points for spring rate change
= 19 points allowed within the first class (1 more point moves it to TTB)

Shocks would be 3 more points we don't have. The inherent TTC class competitiveness on the smaller tire, and budget constraints, just doesn't make sense for us to upgrade the suspension and other parts to make the big tires work on THIS car.

For TTC use this season we do have some small changes planned to make the car easier to drive and maybe a tick more competitive. A change to a smaller diameter racing steering wheel and a quick release will make it easier to see gauges + easier to get into the cabin of this car (after removing the steering wheel and hanging it out of the way).



A full Tilton brake and clutch pedal assembly and firewall mounted Master Cylinders will be going in soon. Those will replace the factory pedals and OEM master cylinder (for zero class points), so we can hopefully get past these crappy reman MC units failing so often. Removal of the OEM plastic brake booster is another failure point we can lose, also.

Next few NASA Texas events:
  • April 22-24 – Texas World Speedway
  • May 21-22 NOLA Motorsports Park – Crossover with NOLA
  • June 11-12 – Hallett Motor Racing Circuit
After that we will add the small over-flares to fix the cut off fender lips, then maybe... hopefully this summer, get some new paint on the body and cage/interior. Check back next time to see what we do next to #Dangerzone to hopefully make it less dangerous!

Cheers,

Last edited by Fair!; 03-25-2016 at 05:16 PM.
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