tygrys

Hi to all
First of all thank you for taking the time to read my post. I own a 2008 C6 Coupe MN6 Z51. I did the following performance related modifications to the car:
1. VARARAM CAI
2. BORLA exhaust
3. Ported TB
4. Tune
5. Michelin Pilot Sport PS2 Tires: Front 275/35ZR-18 and Rear 305/30ZR-19
6. Bilstein shock absorbers
7. LG Motorsports sway bars
8. Stainless Steel brake line
9. Hawk Performance Ceramic Brake Pads
The car dyno’ed 402 RWHP runs great and with the suspension/tire mods I feel substantial improvement in handling and cornering. It is my weekend fun driver as I use a different car as my regular daily driver. This year however I am planning on using it more on a racetrack. As a matter of fact I already went to one race track event this year.

I was wondering what kind of other modifications would you recommend? What I am looking for are modification that:
a. increase the power/torque output (for example the car pulls great on 1st 2nd and even 3rd but then on the 4th and 5th it could do better)
b. improve track performance (cooling, braking, handling etc)
c. do not deteriorate my regular weekend use of the car.

RELIABILITY is my major concern as I moved to Europe some time ago and thus have limited access to corvette mechanics/parts etc. I am handy with tools and capable of performing some mechanical work.

Look forward to hearing from you regarding your experience and thoughts on the subject.
Chris

Bill Dearborn

If you are talking about race track performance on a road course it really doesn't matter much how well it pulls in 1st and 2nd since you never use them except to pull out of the paddock or back into it. With the Z51 you have a pretty large jump from 3rd to 4th so the drop in acceleration when you go to 4th will seem to be exaggerated. Even with the lower geared 5th your transmission has it is still an overdrive and you need to get into that gear at the correct time to make it perform right. My 03Z had the same transmission and on level ground I had to shift into 5th at around 115 to get over 150 before I had to brake before the next turn. If I held the car in 4th to 130 or more it wouldn't reach 150. If you are really seeing a drop in acceleration when in the higher gears you should also be alert to the clutch slipping.

Spending less time in the corners and exiting at higher speeds is the best way to improve your track performance before engine mods. That can be best obtained by getting a decent street/track alignment, improving your driving skills entering and exiting corners and once you are a better driver moving to a set of wheels with track tires, improved driving skills mean you won't be as hard on the brakes but at some time you will want to improve them. For the time being track pads will work fine in your calipers along with some cooling ducts to cool the brakes after you heat them up to 1300 degrees. The stock Z51 brakes will slow the car as well as any big brake kit. They just don't do it as well for as long so if you are running 20 min at a time you should be OK with track pads and lots of cooling to the rotors.

It is amazing how much distance you gain on another car if you can get through a corner a few tenths of a second faster and exit 1 or 2 mph faster. 1 mph equates to about 1.5 ft/sec. So if you exit a turn at 80 mph Vs 79 mph for the other guy and drive wide open for 30 seconds (hitting 150 mph) before hitting the brake you will gain 45 ft over the other guy. It takes a lot of power to overcome that little speed difference.

One thing I haven't done in a while is spend some time making laps around a track with minimal use of the brakes. It can be quite instructive learning how fast you can get around the track without touching the brake pedal. Do your speed control with the throttle and the steering and if you over do it you can always touch the brake as a save your butt measure.

Bill

mikeCsix

Outstanding advice from Bill. I was quite surprised how well my stock GS performed at the hands of an expert which tells me the investment I need to make is seat time.

jon6.0

timd38

I am guilty of of making the car far more capable than the driver. Invest in learning how to drive before you get to old to learn.....

tygrys

Thank you Bill and all for you feedback.
I could not agree with you more regarding seat time, i think it is the most rewarding and satisfying experience to see effect of one's own improved driving skills. I have had a chance to complete a performance driving school workshop on a Goodyear racetrack in Luxembourg and have been practicing myself as well. It is plenty fun and I will continue to do that. I asked the question also because in about a month from now I will be traveling to the US so thought that if I needed, I could buy sth and bring it back with me

Regarding the gears I was indeed referring to drop in acceleration when shifting from 3rd to 4th, which I could feel very well on the main straight one the track, exiting from the last turn on the 3rd and then going into 4th. Thank you for the advice on when to engage the 5th, I will certainly try it out. Until now I have been trying to stay on the 4th until the end of the power band and then shift to 5th. I'll see the difference soon.

Regarding the brakes and cooling. This is actually my 1st point of interest right now, two weeks ago while on a track, at the end of the session my brakes got stuck. I think the major source of the problem was the fact that I did not use racing type brake fluid so I think the regular one just boiled and melted the seals on the pistons in the calipers and then pistons then did not want to go back. I am getting this fixed right now and changing the fluid as well. However I was wondering if there is a way of improving the cooling of the brakes? Should I think of improving cooling of other fluids/systems (transmission, engine cooling, etc)?

Adam@Amp'dAutosport.com

You need to change fluid to a DOT4 and do not use those ceramic pads on track get a set of dedicated track pads like Carbotech XP10 and XP8. They make a few diffrent cooling duct kits just search you will find a lot of info on them.