tshirttom

I am fairly new to autocrossing and wondering what specs would be good for rear wheel allignment on a C4?

What about tire pressures front and rear?



Apreciate your input.

jaa1992

I think VBP has an alignment guide on their website. I don't have a link to it.

How much negative camber can you get in the front?

I get 0 negative camber in the front so I'm only running -0.5 in the rear.
Tire pressure is dependent on:
What tires?
How many heat cycles?
Autocross or road race?
How long of a session on the road race and how much camber?
Got chalk and tire pressure gage? take a notebook and keep track of it all.
Find what works for you.

Kubs

It depends on a lot of things. On my car I got -2 degrees front, so I ran -1 rear with about 3/16 toe in. I also have solid heim joints instead of the rubber bushings in the back so it held the alignment very well. It works very well on a roadcourse but it was just ok on autocross.

tshirttom

I am running street tires all around -Pirelli p zero 235/30 Zr18's

I have the Banski rods on the back so I can easily adjust at the autocross but won't have the same luxury on the front.

Solofast

We typically ran -1.25 to -1.4 degrees in the back of stock class cars.

You never want to "dumb down" one end of the car to match the lower grip at the other end. Get as much as much grip as you can out of BOTH ends and then adjust sway bars to get it back into balance. Even if you have to soften the front bar (or if the class rules allow it stiffen the rear).

Just because you don't have a lot of negative camber in the front doesn't mean the back can't get you more grip. Get more grip in the back, and then readjust the balance to take cornering load off of the front and you will be faster.

With that much negative camber you will put power down well coming off of corners and the car will be stable so you can put it down earlier. If you use less negative camber you won't put the power down, you will eat outside edges of the tires and it won't be fast.

Solofast

Tom,

You really need a set of 275's for that car. 235's aren't enough tire. It will likely push without some bigger meats up in the front. I know tires are a lot better now than back when I was running C4's, but we never got them to work well at all unless we got 275's all around on them.

tshirttom

Mistake

Sorry it was dark in the garage. I am running 285's all around not 235's!