VettChick

550RWHP: What's the optimal rear tire pressure for traction:

Toyo R888 305/30/19's?

C6 Doberman

Not sure but I really don't think it is going to matter at the rwhp.

Mike V.

I agree, but you might need to clarify for what (i.e. at the drag strip, road course ,everyday,... also on what size rims) to get a better answer. I would say no lower than 20lbs at the strip & no lower than 25lbs daily driving. If you goal is super traction it just isn't goin' to happen, but strong launch skills will be way more important than tire pressure!

rovers2000

30 lbs works good. launch control is also important.

PowerLabs

Horsepower won't change the ideal pressure on the tire

I run mine at 30PSI all the time; they wear faster and are more prone to damage if you run sub optimal presure on them. For autocross/road racing, I found 34PSI to be ideal. My best launches on the drag strip were at 16PSI, but it is entirely possible that that was too low and it may work better around 20PSI (the number I've been suggested before).

BlownStealth

Would looser front shocks help traction?

PowerLabs

Probably not / Not necessarily. Softer rear springs/shocks would help more, but for that your car will handle like crap... If that is an acceptable compromise you could always just sell the Corvette and buy a Mustang... It will be cheaper and get better traction, the solid rear axle is more durable, and making power on those is cheaper too. My buddy had a Fox Body with a turbo that ran 9s, and he put about 12K into the project. The handling was undescribeable; we almost went off the road taking a shallow turn at 40mph. It handled like a lifted pickup truck.
They don't stop or turn as well as a Corvette, but the handling and stopping should be comparable with a corvette set up with soft springs and shocks for launching

To improve traction (in order of compromise):

- Sticker tires (the R888s should be good)
- Less air pressure on the rear / more air up front
- Lower the rear
- Remove weight from the front (headers instead of cast manifold, high flow cats / no cats, lightweight clutch, lighter brake rotors, lighter wheels, lightweight battery)
- Add weight to the back (relocate battery, fill up the gas tank)
- Softer rear shocks (may cause wheelhop)
- Softer rear springs
- Remove front swaybar
- Softer front shocks and springs

My car is hardly the example of what a drag car should be, but I can just about hook up 600RWHP in 1st gear if my Nitto NT-555R2 (almost identical tire to the R888, with the same rubber compound) rears are hot. I run them in 305/35R18

BlownStealth

Thanks for the info. Just got the R888's. I really thought they'd hook up better. Great suggestions though. I guess I have to work on using my right foot!

May be a wide body conversion next year with 18" 345's!

dbsears

Beauty of the vette is you can make it handle VERY good and still have great traction. If you don't want R comps on the street RE-11 are very good and are available in 305/30/19 and 265/35/18. Step down from R888 not being an R comp but will give you 8/10ths of the performance with twice the mileage and still one of the stickiest street tire you can buy. Me personally I would go with R888 but WA rains more than it shines so RE-11 is about the stickiest tire you can by that won't kill you in a torrential downpoor we commonly see all of a sudden.

Questions for PowerLabs...how is the drivability on those R888's? Quiet/Loud and how many miles do you think you can sqeeze out of them. I am used to driving RE01R daily but that amount of traction is very temping.

BlownStealth

Can the C6 "traction control" be utilized or MODIFIED for spin control in hi performance street apps?

I have the A6 auto. When traction control is on, the wheels still spin a lot then the motor just bogs down.

570RWHP

PowerLabs

Did you heat cycle them properly?

R Compounds do not hook AT ALL unless heat cycled properly.

PowerLabs

They are about as loud and stiff as the run flats on most roads.
I was told to expect 9 - 12K miles out of them. Can't comment on that yet...

In theory yes. LG claims to be able to do it. I haven't seen anyone do it. My car with T/C on still does epic burnouts; my traction control has no authority over the car.