Datawiz

For Autocross

If Frank Gonzalez is anywhere around, I'd like to hear from you. Dave Lehman said to ask for you. I think you've run at Buckingham, where I run.

Anyways, I just recently took posession of my '08 Z06 and my fresh Hoosier rubber. Dave said I should have it aligned to add camber. What settings should I use to improve my racing, but not be so radical that when I put my street tires back on, I won't beat the hell out of the street rubber. The car is a weekend/race car.

TIA

davidfarmer

-1.7front, -1.25 rear.......good comprimise. I'm running -2.2f and -1.5rear, but I'm willing to give up a little on the street for more at the track. Bring er' up and I can corner balance and align for you.......

Datawiz

Thanks! I'll give it a shot.

95jersey

If you PM me, I have a full spec sheet that shows moderate, med, aggressive. The C6Z has very soft bushings and moves around a lot under load. You may not find anything under -2 to be enough in the front.

Solofast

I have found that you beat up the race tires a lot faster (and it costs a lot more) if you don't go to at least -2 degrees on front camber and about -1.5 or so in the back.

If you set the car with some toe in (1/8" total toe) in the front with -2 degrees of camber, you will get about 20,000 street miles from the front tires, assuming that you flip them on the rims at about 10,000 miles... Mark your tie rods and then put one full turn of toe out on each side for autocross and that will give you good turn in, and then set it back when you take the stickies off...

If you don't go high enough on front negative camber you will chew up the front tires in a couple of weekends on concrete or other abrasive surfaces. If you have enough negative camber you can run a season on the Hoosiers and get good life out of them...

Datawiz

This is great news. Thanks for the info. At $1,300 for the rubber alone to run SS, I'm all for making it last a long time. Where I'm racing this weekend (for fun only), the surface has a LOT of grip, but is very brutal on tires. Unfortunately, I won't be able to make any changes by then. I hope I don't use up the Hoosiers in 1 weekend. I will do some laps on the stock rubber as well, hopefully setting a nice baseline on the mile course for street vs. race rubber.

jlvink66

I agree with Dave's recommendation; -1.7 front and -1.25 rear. I'm running your exact tires/wheels with this alignment on 2-3 mile road courses. I have been measuring tire temps and they are pretty uniform across the treads both front and rear running 41-42 psi hot front and 40-41 psi hot rear.

As Dave mentions, this is a compromise setting. On my street tires I have noticed some accelerated tire wear on the inside fronts at this setting. Any more negative camber and you might not want to drive it much on the street.

John

gonzalezfj

Hey, Datawiz, sorry for the delay in answering you. I have been out of the country without internet access.

I run a pretty radical alignment in my C6Z, but it would not be friendly to street tires.

I agree with David's recommendations: about 1.7 to 2.0 degrees of negative camber in the front and about -1.25 to -1.5 in the rear.

Enjoy. Feel free to PM me if you want to discuss this further.

the blur

The answer is to run higher pressures in the hoosiers to preserve tire life.

gonzalezfj

Not really (in my experience)... The new generation of Hoosiers (R6 and A6) like lower pressure than former designs.

Both my C5Z and my C6Z run with HOT PRESSURES of 30 front and 26 rear. Tires don't cord and the grip is outstanding.

YMMV.

Frank Gonzalez

the blur

You can certainly run faster with lower pressures, but unless your running -3.0 camber the outer edge will cord will fast..... in my experience. And it cost me a front tire already. So I run 32 / 27 now.

jlvink66

Wow, those are way lower pressures than what I've been running. Have you been measuring tire temps? I've been gradually raising my tire pressures to the point now where I have fairly constant temps acros the tires with 40-42 psi hot. Is there maybe an inconsistency between what is fastest and achieving even tire temps?

John

Solofast

Frank is right the later gen Hoosiers are perfectly happy with lower pressures and work great there, PROVIDED YOU HAVE THE CAMBER RIGHT. If you don't have enough negative camber you can try to compensate with higher pressures, but then the tire doesn't work that well. The -2 degrees is the right number guys, this setup works..

Put in the -2 degrees and enjoy it. The street wear isn't that bad. The real issue is toe out. Toe out will destroy the street tires in no time, but if you reset toe when you change tires it just isn't much of an issue.