MartyZ51

Here's my track experience with an '08 Z51, NPP, 6 speed that may be helpful for some people hoping to track a C6:

PCA three day advanced Driver Education event at Heartland Park Topeka. I have 8 years of track experience with Camaros at various tracks in the midwest. This was my first weekend in the Corvette.

Modifications: Hoosier R6s (Tire Rack) mounted to 5 spoke stock take-off rims, Quantum brake vents with 3" hose (street hose is fine), -2.1 degrees camber on the front and -1.1 on the back (NTP). Carbotech XP10 pads on the front and XP8 on the rear. I flushed the system with Autozone Dot 4 fluid using newly installed Earl's Solo Bleeders (LG). Greased the rear tie rod ends and wrapped all four with heat shield tape to prevent them from melting. GM splash guards (Gene) were added to help reduce rock chips from the slicks as they are wider than stock. The TPMS reset tool from Katech and the TPMS sensors (House of Wheels) worked flawlessly. I don't subscribe to On-Star but I pulled the fuse at my house beacuse I could feel the black helicopters circling overhead. The car is a 3LT with HUD and without floor mats and with a 1/2 tank of gas it scaled at 3230 pounds.

I ran the car very aggressively and generally had 1.52 minute lap times. The Porsche Club race 944 winner's best lap was 1.48 in the same conditions. The oil never got above 285, the highest I saw the G-meter reach was 1.17 (banked corner to so who knows what it really was). I left the competitive mode on most of the time and did get the active handling intervention message on about 1/3 of the corners. It must not be tuned for slicks because the car didn't want to push out but it did make me feel very safe. After a long cool down, the front rotors generally ran 195 degrees and the backs were 75 degrees more. I assume they were more because the active handling was working them and I don't have an axle mounted duct. I took the temps after a session with all stability control off and the rears were 30 degrees lower but still higher than the fronts. A three section width tire temp and the tire wear indicated not enough negative camber. After 350 miles on the track the back R6s are 1/2 gone and the fronts are 80% gone. I'll flip them both to get a fresh edge on the outside.

The only mechanical issue was in wet conditions at the top of third gear the speedo would sometimes go to zero and then engage again to about 120 MPH when I got into fourth.

My conclusion:
The C6 Z51 is a world class track car that is extremely competitive with very little modification. Hoosier slicks are expensive and I'll move to take offs or Kumhos for the front. The single biggest improvement I could make to the car beyond the driver mod is a set of 18" CCW light weight wheels. I test fitted a C5 ZO6 18" rear to the front figuring I could run these on all four corners but wasn't comfortable with the clearance. This would be more of a pocket book improvement verses a performance improvement allowing me to run take-offs. I will reduce my brake pad aggressiveness one notch front and rear to save rotors. I'll be looking for a better rear brake duct solution to get my temps lower than the fronts. I experienced no brake fade and didn't bleed the brakes all weekend so I won't be buying stainless pistons or lines and won't buy expensive fluid anymore. I will probably switch to a Z06 or some other larger oil cooler. I think it will be hard to stay below 300 degrees when it's 90 outside. The car didn't burn a noticeable amount of oil and I topped it off as indicated in the manual. The intake, engine, and exhaust are stock with the exception of the Nakidparts NPP controller. I'll be keeping them that way as the car doesn't need any more power.

I hope this encourages some new owners to get their cars out on the track where they belong!

LS3FORME

I echo you points, I am a PCA instructor, same car as you, Vy, 08 Z51 NPP 6spd. Running the car this weekend at homestead, Lowered on Harbar bolts, running Hawk HP+( for rotor life), front brake ducts, second set of 08 split spokes with toyo r888, 245/24 f 295/30 r. I did however, upgrade to motul fluids. The clutch fuild last a little longer. The oil temps in so fla get hot, I have hit 290 during the summer. The car can hang with a 997 gt3rs on the straights. I do not push it to 10/10 but it does not need more power, Going to align it this friday, the R888 do not need as much camber as the R6 but that is pretty impressive amount of camber for a street car.

This is my 4 trackday with the car. Getting comfortable with it. great car for the price.

B/Stock

Thanks for the informative post. What did you think about the handling with the active handling and traction control off versus competitive mode? Did you make any runs with both TC and AH on and if so what did you think? It would be interesting to get some temps with the Quantum vents off & see what the difference is.

MartyZ51

I did leave TC and AH on when the track was wet because I didn't have rain tires. Basically, the TC would completely bog the car down when left on. I think the Competition mode is tuned for the summer street tires that come on the car and probably works really well allowing a certain amount of slip. I only ran 2 times with everything off and as I said the the rear brakes were cooler. I wasn't running 10/10 but really getting used to the car and learning to feel safe. My last 2 cars would allow you to 4 wheel drift out at the top of sweeping corners when you applied throttle at or before the apex. I imagine this car will be the same with everything off once I feel comfortable with it.

MartyZ51

I forgot to mention the clutch fluid. I had all kinds of trouble with my Camaro and the clutch sticking to the floor. Transmission was behind the motor and the line from the reservoir ran right by the catalytic converter. I ended up wrapping the line with heat tape and removing the transmission to install a remote bleeder line. I learned the pump and flush method on this forum and it saved me a ton of time. I'll have to pass that video clip on to the F-body guys!

I also ran with the GT3s on the straights. The two I was with had slicks and open exhaust and had to be more than 425 HP. It's hard to tell how hard they are pushing their cars or if it's all about corner exit and the line each car takes. I would probably be very cautious running a car I paid $107k for at 9/10s for a track weekend.

I need to figure out the tire/wheel issue quickly. I took a closer look today in the garage and one front is corded with the other one close behind. This is after 3 days and around 350 miles of track time. slicks are a lot of money but it seems like a step back to go without them.

BEZ06

Wow!!! Excellent report!!!!! Thanks very much!

Can you clarify your comments regarding the AH?

You seem to indicate that you think the rear brakes were heating up more than the front due to the AH.

I've owned a C6 for 4-1/2 years now and have tried to learn about the systems on the car. However, there are a few systems that are still mystical black-art systems, and the AH is one of them. However, all the info I've found indicates that the front brakes are the ones that are used during AH intervention. Here's what the Service Manual says:

Maybe I misinterpreted what you said, or maybe I don't understand the AH well enough (I know that's true!! ), but if the Service Manual info is correct, then it sounds like only the front brakes are applied when the AH is working.

Standing by to be educated about the AH system!!!

Bob

MartyZ51

I'm not an expert on the active handling but the difference in rear brake temps compared to the front could be attributed to:
+the fronts having direct vents to the spindles and the long cool down laps I was taking.
+too aggressive pad compound on the back verses the smaller mass of the rear rotors causing them to gain more temp.
+Active handling pulsating the inside rear brake to prevent oversteer on hard cornering

I'm sure there are Active Handling experts on this forum but my plan is to go without it once I feel comfortable. I can't imagine GM calibrated this system for slicks, high degrees of negative camber, and excessive speeds on corner exits. I would imagine they set it up to allow a driver in typical situations to experience a limited amount of slip to have fun. I'll know I have arrived when I can consistently beat the competitive mode track times on my own!

rustyguns

the rear brakes get fricken HOT with the active handling on!
believe me!

DarkMastyr

How did you get so much camber on the stock suspension?

EvilBoffin

David Farmer did the alignment & corner-balance on my '08 Z51, and told me that we could get as much as -2.5 camber on both front sides. Not sure if that's unusual for a non-Z06 C6, but it didn't seem to surprise him.

MartyZ51 - How far off were the temps across your tires? Did it look like you need a LOT more camber, or do you think -2.4 or so will suffice? I'm running -2.0f/-1.1r now, but feel I should go to about -2.4 in front. The extra wear on the outside shoulder of my A6's seems to show that more negative is needed to keep Hoosier's happy...

.

flink

Yes, you're measuring the cooling rate there more than anything else. I don't
think you know whether the rears were overheating, frankly.

Try putting some temperature-indicating paint on the rotors, to measure the
peak temperatures. I use MD-GEN-GB1000 from moto-delta.com, but I'm
not terribly confident in what it tells me - it always says 1500F, front and rear,
even as I added successively more ducting. Then again, I was driving harder
each time too.

1.17G's doesn't sound much - I'd expect over 1.3 on those tires. But it sounds
like it was wet a lot.

flink

No I don't. I use GB7000:



and I always get this color:

MartyZ51

I believe with the suspension geometry you can get more negative camber the lower the car is. My car is on the stops in the back and one inch lower than stock on the front. there was one side that limited it so we made both sides match.

Bob815

What size R6's were you running on the stock wheels?

Thanks
Bob

MartyZ51

The rears were 315 30 19 and could have been wider. The fronts were 295 30 18 and were as wide as I was comfortable with. I'm going to flip the rears to put the fresh edge on the outside and the fronts are done after 3 days.

Marty

Datawiz

G-force ratings seem very low for Hoosier R6's. I saw 1.24 at Spring Mountain in the Z51's on stock Goodyear Runflats.

I frequently see 1.35 or more in my Z at the autocross track with my Hoosier A6's on my Z.

Great write up nonetheless.

jadkins

100% agreement - I have the "Track Special" C6 myself 2008, z51, NPP - no HUD pretty much zero optioned car except NPP. Mods wise - I am running smaller C5/Stock C6 brake rotors (cheap/disposable), this also allows me to run 17" CS/A-Mold clones with 315s Kuhmos on all for corners. All NANNIES turned OFF. Wilwod/Carbotech 2008 and Hawk (for 2009) Alignment/Corner weight by Danny Popp.

Best time was a 1.18.7 at Putnam Park. I did find that 285temps on the oil were a little much so for this year I installed a C6 Z06 Oil cooler (used $240 from Katech) which is about 3times the size of the stock z51 cooler - hopefully it brings down the temps on the hotter days. But even with the stock cooler if the temps went up I would simply let everything cool down for a lap and would be ready to push it hard again.

Bottomline with new Kuhmos (or better yet Hoosiers if you can afford them) this car is super easy to drive (Danny P's setup is second to none!) and will make you look like a superhero in most run groups, even with heavily modified cars. But I will be the first to admit the car is way beyond my skill level - and saved my butt several times last season when I made poor decisions.

I spent about 5 year autocrossing an 89' Saleen Mustang in the early/mid-90s, 3 seasons open-tracking a 2002 Subaru WRX (another easy car to drive fast), 1 season open-tracking a 2000 C5 coupe, and last season in the 2008 C6 and can honestly say the C6 is by far the easiest to drive and will produce low laptimes just about anywhere - even with a mid-level driver behind the wheel.

Feffman

We (www.MVPTrackTime.com) have a good turn out of Vettes at all our track events and anyone who thinks the Vette, particularly the C6, is nothing short of great, both on and off the track, is simply arrogant.

The first year the C6 Z06 was out, one of our instructors who switched from tracking a BMW M3 to the Z06 set the fastest lap of the day on the stock run flats by nearly three seconds over a number of cars running on R compound tires.

Feff

LS3FORME

Update on this topic. Sat. Homestead Grand Am road course. C6 z51 npp, 6sp. First run with the new R888, excellant tires for dual purpose useage. Learned alot of interesting stuff, A race team will not disclose, building a c6 racecar was there testing. Spent alot of time with the tech/owner, new stuff, even with active handling and tc off the GM system still keeps some nannys active. How do I know ,the C6 race team was reengineering the software to get the factory abs back in check with the custom stop tech brakes and the systems would as all have said kick in the rears even with all electronic defeeeted.( cracked rear rotors) So even with everything off it is still there. Ran several laps in comp mode and several in all off, and several in all on. The abs and the AH handling features are much more noticable with the DOT R, I got into abs several times but what really go my attention was the rear brakes where baking even with everthing off after about 5 good laps. This got me thinking about the software and it's inherant trait to kick in, so I went back to the c6 team driver owner, posed the question. If the comp mode has built in parameters which are known to allow some slip angel and aggressive driving style. If you turn all off but it still is there in the back ground do the parameter of the system have limit, upper and lower slip angles, yaw, wheel spin, etc. I guess a programer could go into the coded and figure it out, anybody done this. The car after every thing I tring felt the best in comp mode. Ps the r888 like high pressure 43f/44r on track. They kinda found a balance at that sweet spot, below lost some communication, above got slippery. One other thing the Dot R make the z51 suspension show it's limits, on the high speed 180 not a hairpin, but T7-8 homestead the body roll was very apparent with the stick of the toyos.

Abbott

Is the C6 more capable than a C5 Z06 in the same hands and tires?