Level8Drummer

Hey everyone! I've got a 2002 Z06, 100k miles.
I've done a few reliability mods: bigger radiator with oil cooler, trans cooler, diff cooler, replaced valve springs and seals.
A few performance mods: containment seats and 6pt harnesses, wilwood front calipers, ss brake lines, Carbotech RP2 pads, ridetech delrin bushings, Bilstein shocks, T1 sway bars.

Running 305x18 continental G5000 takeoff tires square, camber is 2.2f/1.3r, ride height is stock.

No other performance modifications.

Car weighs in at 3209 with a full tank of gas and no driver, and dynoed 340 on a mustang dyno.

I live in Greenville SC, so I frequent Road Atl, Roebling, VIR, and AMP.

I've been driving a while, but the vette is a new animal to me (came from the BMW world). I've been keeping my max RPM 6000 for reliability. Tires have a couple of weekends on them.

I was at Roebling road this past weekend with the PCA, and I managed a 1.21.5 in 96 deg heat towards the end of a session, only got 2 clean laps, lots of cars out there this past weekend! Max lateral acceleration was 1.15-1.23 G's throughout all the laps. Braking was about 1.1. Top speed was 137-139 throughout the laps.


Do yall think fresh hoosier A7's would be worth a couple of seconds? What other setup changes should I make to make the car more TT3 competitive?

Thanks!

Level8Drummer

StreetSpeed

A7 would probably be good for another 1-2 seconds. I've used the G5000 scrubs - they suck by comparison. Looks like 1:19s would be competitive in TT3, fast guys are 1:17s. Looking at the results from April I think Mark Nunnaly ran his TT3 car in TT2, and he ran a 1:13.something. So if he shows up you're in trouble.

Keep in mind your average power on a dynojet might be a bit high. If a Mustang is 10% low, then your power on a Dynojet could be 370. TT3 is 10:1 average HP. So if your car weighs 3200, you weigh 200, and you roll across the dyno at 3400lbs, that means your car has to have an average power of 340whp or less. So I guess you'd probably be OK, but you'll have to get in on a dynojet and run the calculations to be sure.

I say throw some Hoosiers on there and let it rip!

Level8Drummer

Better than Continentals?! Better than McDonalds!

I can't imagine more grip than that. I'm afraid my lungs will fly out of my mouth!

Good info, thank you!

Do you think I should try to get more negative camber up front? Haven't had a chance to check temperatures yet, just trying to ballpark it and go from there.

Level8Drummer

StreetSpeed

If you're on stock rubber bushings then you'd probably do well with a little more camber, but tire temps tell the story better than some jerk on hpthe Internet. Fwiw I used to run about 2.5 degrees up front with stock bushings and my tire temps were pretty even.

Level8Drummer

I have ridetech delrin. I did not get a chance to get tire temps at roebling last weekend, had 2 students! Definitely will at Road Atlanta in August with Chin.

Alex

C5Z06CE

I would suggest lower the car a bit. Try 315/18 square setups and R7. I also would look at lower tire pressures for even more grip. I tend to start around 26-27 psi cold and they heat up to 35 psi. If you haven't already get the car corner weighted and balanced. It helps handling. Lastly, get rid of some weight. My car is gutted but with a full cage AND driver it weighs in at 3180.

brkntrxn

The tried and true TT3 formula with a C5 is the following:

- get the weight out!!! Strip anything that is not necessary to go fast, brake late, corner quickly
- set your hp to the max ratio allowed
- sways
- for TT, you really do not need a BBK. so just a super aggressive brake compound will do it. however, getting BBKs or at least two-piece rotors will reduce the amount of time you spend in the pits changing rotors
- the widest A7s you can run. run 275s if you want the hp bump, or run 315 and greater
- balance and corner balance the car
- if you keep the leaf springs and shocks, get a set of new 2004 OEM shocks. they are a bit softer than the 2003 and older shocks and allow a bit more of a set when turning into the corners

The above will get you into the lower end of the podium and make you competitive. With what I described above, the CAR will be capable of 2:05's at VIR, 2:17's at Roebling, 1:35's at Road Atlanta, and 1:41's at CMP.

If you want to be on the pointy end of TT3, the CAR needs to be capable of running 1:59 at VIR, 1:29 at Road Atlanta, 1:38 at CMP, and 1:14 at Roebling (this is where this record should be). To do that, you are going to have to go after all of the hard stuff like: button clutch, headers, lexan, carbon fiber panels, functional aero, better springs/shocks (leaf or coilover as both work), lighter weight, perfect balance, sticker A7s for flyer laps, meteorological degree to forecast the weather, don't-give-a-damn-****-at-11, and willingness to put it in the wall and walk away with a smile on your face.

Once you get the CAR capable of running those times, you need to ensure the DRIVER can do it as well. I am here to tell you that there is a HUGE difference in your adrenaline level between the lap times I posted above in TT3 trim.


You live right in the middle of C5 Mafia geography. Ha, so you need to expect any one of them to show up at any of the tracks you listed.

Level8Drummer

Thank you everyone! Great information.

sperkins

I'm in middle GA and would be willing to help anytime if needed.
Scales, setup, mechanical etc..

Scott Perkins

wtb-z

At the "lower end of the podium" range how many laps/TT sessions/TT days do you think a set of A7s be worth running for? That seems like a big part of the operating cost.

StreetSpeed

Lower end of the podium meaning not trying to win? I can't really speak to TT, but at my last race weekend I was running A7s with 13ish heat cycles on them, and switched to sticker A7s for qualifying and only went .6 seconds faster. Mind you this was my first time driving my car with real suspension and solid bushings, so I was learning a lot, but still the "older" A7s weren't drastically slower than the fresh ones in my case. Still lots of rubber left on them too. I would imagine that if your setup is right you could get 18-20 HCs out of A7s, but I have no idea how well they would perform at that age.

sperkins

You're asking Mr. Stickers how often to run new tires?

brkntrxn

LOL, that is funny!

Sticker As to a 4-5 heat cycle A can be as much as a second or more per lap. 8+ heat cycle As will not even keep me near the front of the TT pack and will only be used for TT warmup and lapping. 12+ heat cycle tires are relegated to lapping duty or sold.

Does it matter? Yes when you are separated from your competition by tenths or less. Last Sunday, I won TT2 at Road Atlanta by 71/1000 of a second on tires that had four TT sessions and four races. But that is by far, not the norm. It all depends on who shows up.

drivinhard

Tire size plays a huge role in this. Spent a lot of years back in TTA on the 255/275 sizes, and played around with the bigger stuff the last couple of years. There is a very large difference in tire life, and actual tire "speed life" in the 315/335/345 sized tires. I would put the usable "speed life" of the bigger tires in the 3x range over the smaller tires.

If you have wheels to put them on, the big tires are the way to go, if nothing more than they are cheaper since they last much longer.

Level8Drummer

Are there any affordable wheel options to run "huge" (315+) tires on?

Level8Drummer

brkntrxn

If you are rich like my competitors, you can purchase proper 18x11 or 18x12 wheels from the big names like Fiske, CCW, etc.

If you are like me with two kids in college, you can simply run rear C5Z 18x10.5s. However, the contact patch of a 315 on a 10.5" will not be nearly as wide as a 315 on an 11" or 12" wheel. What I give up in contact patch, I saved by buying used OEM wheels from the waxers. Via Craigslist, over the course of a year or so, I was able to collect 16 rears. When I had to, I would buy a full set and sell the front 17x9.5s to the drag racing crowd.

Level8Drummer

Haha! Then you are like me. I have 2 full sets of C5Z wheels, and an extra pair of rears. One set has my street / DD tires, the other 4 rears house my 305 Conti takeoffs that I run square.

Level8Drummer

blueekb

I don't mean to derail the thread but dumb question... I'm rebuilding my car now.

If we have to detune what's the point of headers? Just lighter weight or do they really help with torque that much?

$1500 for actual lower lap time? I guess is what i'm asking.

drivinhard

I am surprised by Kevin's data on his min apex speeds and lateral G loads on 315's on his 10.5" wheels. They are good enough (granted his car has a lot of development) that if you have stock wheels and don't want to spend $$ on aftermarket ones, that you should absolutely go that route. I don't think they "Feel" as good since the wheel width doesn't really match the ultimate tire width, but in the end, you can't argue with the stopwatch.

drivinhard

It's a whole lot easier to work on the car with the stock exhaust.

Not sure where you are with your car build/development, but I would probably spend that $1500 on other areas of lap time for more bang for the buck.