C5_Z06

I've read alot of old threads trying to get a good understanding of what I should aim for when I have my car aligned. I still have some questions hence this post.

The car in question is a C5Z06 with the full T1 chassis kit. I use it as a weekend toy and also attend HPDE's. I do probably 75% spirited street driving and 25% road corse track time. I never do any auto-x or competitive driving. Car has C6Z51 brakes with Stoptech pads. I run Michelin PS2 street tires in 263/35*18" and 295/35*18" on stock 18*10,5" wheels. I'm now trying to decide what alignment spec is best for my driving habits. I have no plats to run R888 or similar track tires, so basically I know my car is a compromise. So here it goes:

Camber: I plan to run 1.2 front and 0.8 reas, is that to little?

Caster: As I understand the more the better? Stock Z06 spec is 6.9, non Z06 have 7.4? Shouldn't the more performance oriented Z06 then have more caster? I don't get that, can somebody explan this? What should I aim for here?

Toe front: Stock values for the front is 0.04 degrees per side => 1/32" total toe in if I calculated correctly. Is that a good starting point? I understand to much toe eats tires, and that I want to avoid.

Toe rear: Stock value specifes a small toe OUT of 0,01 degrees! I couldn't find anybody recommending that here. It's usually toe IN that is also larger than up front (generally twice the front value). Can somebody please explain this? I read that for a rear wheel drive car it could be good to have a small toe OUT set since the wheels move towards toe IN during acceleration. Currently I have 0 toe in the rear and the rear end gets very "lively" if I accelerate hard on an uneven surfae like the white markings in the road. I definitely do not want this behavior. Can that be affected to the toe setting?

I hope I didn't bore you to death, but I couldn't find any conclusive answers the the questions above. I'm looking forward to your input.

mgarfias

I'm not on a T1 suspension, but I run -1.5 up front, and -1 in back. What kills the hell out of front tires is toe out. On the street I run a smidge of toe in (probably about that 1/32" or maybe a bit less. Not that I want toe in, I want neutral, but when we set up the car its not moving and the suspension isn't loaded and deflected. I've found that when I set 0 toe statically I end up eating the tires' inside shoulder, so I crank in the smidge of toe in.

At the rear I run 1/8" toe in. I think I'm running about 6deg of caster, but when I get around to it, I'm going to realign and get as much caster in as I can while still getting the camber I want. Less caster makes the car twitchy and responsive, more slows down the inputs a bit, but also plants the outside tire in the corner.

Also, before you align, you should disconnect the anti-roll bars, and corner weight at your desired ride height. Reconnect the bars, drive around the block a few times, then align.

torque*is*cheap

The autocross guys run a fair amount of rear toe-in (1/8" or 3/16") for better traction on exit, but then again this is the extreme case...hard 2nd-gear acceleration out of really tight corners.

C5_Z06

That makes sence. Iv'e been running 0 toe up front as well and got wear on the inside shoulders. I'll go with stock setting.

What about rear toe then, why are cars setup with that much toe in? Don't you want neutral in the rear as well to avoid tire wear?

Will I notice a big difference by going from say -1.2 to -1,5 camber?

How about caster, anybody know why the stock C5 has more caster compared to the Z06? Isn't more caster always better? Or is it beacuse the Z06 has more static camber?

mgarfias

For some reason the rear doesn't wear the outside shoulders with that much toe. I imagine if you went to something like 1/4" you'd see it, but thats excessive for the street.


I don't think you'll notice much difference between -1.2 and -1.5. On the track you'll wear the outside edge with either -1.2 or -1.5.

C5_Z06

Thank you. I still don't get castor and rear toe, see below. Any input?

Caster: As I understand the more the better? Stock Z06 spec is 6.9, non Z06 have 7.4? Shouldn't the more performance oriented Z06 then have more caster? I don't get that, can somebody explan this? What should I aim for here?

Toe rear: Stock value specifes a small toe OUT of 0,01 degrees! I couldn't find anybody recommending that here. It's usually toe IN that is also larger than up front (generally twice the front value). Can somebody please explain this? I read that for a rear wheel drive car it could be good to have a small toe OUT set since the wheels move towards toe IN during acceleration. Currently I have 0 toe in the rear and the rear end gets very "lively" if I accelerate hard on an uneven surfae like the white markings in the road. I definitely do not want this behavior. Can that be affected to the toe setting?

mgarfias

Caster: no idea why the base c5 calls for more than the Z. If I had to guess it was to make the Z feel a bit more lively to the average driver. I'd run as much as you can while still getting the camber you want.

Toe: I don't know who is smoking what. I'd never drive a car with toe out in the rear. Makes the car want to swap ends. Also, you can monkey with it yourself. Set it to 0, then give it a turn on each side (mark the tierods so you can go back) either in or out. And drive it and see if you can tell the difference. If not, add another turn in the same direction. Also, toe in at the rear helps plant the back end under hard acceleration out of a corner.

PA Z06

Shoot me a pm and I will send you a very helpful alignment spec sheet from Pfadt

C5_Z06

Is this what you are refering to?

http://www.pfadtracing.com/blog/wp-c...-alignment.pdf

Bills Z06

I've used these setting and they seem to work pretty well.

C5_Z06

Thanks for all the replies, much appreciated, I'll go with what's been recommended.

For the sake of learning though I would really like to get a better understanding of the two questions above. Anybody have any more input?

TS Motorsport

Bushings are the key to running a lot of camber, caster & toe on the corvette. If you're on OEM bushings, you are limited to the amount of movement the bushings will allow.

C5_Z06

I thouht it was the other way around? Hard bushings like poly allows for less movement hence you don't need to run a high static camber to compensate for flex in the bushings while cornering?