Sox-Fan

I sent out my 04 z06 to have the rear seals re-done and it came back sitting low in the rear. If I'm going to change the way the car sites I may as well put it on scales and put it where it belongs rather than simply tape measuring on the frame and setting it level or maybe trying to eyeball in some rake.

For a car that's daily driven, will see two or 3 track days, and 12 Autoxes what would you set the weights at? More nose weight for better braking?

Hi Volts Z06

I'm assuming you have coilovers. C5's like about an inch of rake to the front. Regardless of what your use is, you should always try to corner balance the car with you (or someone or something of your weight) in the passenger seat and you should be looking for an equal cross weight measured diagonally (meaning add the left rear weight to the front right weight and vice versa) in order to achieve the best balance.

Sox-Fan

I don't have coil overs. Apparently they cranked the bolts down on the back to where it sits lower in the back. Would adjusting those bolts not move weight in some form or fashion?

Hi Volts Z06

I thought the only method of lowering a stock monospring was to use a longer bolt. Regardless of the method- it's wrong because it changes spring rate. When I purchased my C5 it came slammed to the ground (FL car) but here in NY with the hills (and potholes) I ended up putting in coilovers to raise it up and get the suspension geometry correct. The car is now a dedicated race car so it really doesn't matter but I can tell you that it's important not to lower it too much regardless of method because you basically have almost no travel and it's counterproductive.

Sox-Fan

You can change the ride height by cranking up and down the so called "lowering bolt" at the ends of the springs. Mine were not really lowered at all. Now the back is squatting. It's not where I want to be for all the reason you have mentioned. I'm sure that raising the car over the springs again will move some weight, so the question is, what's the optimal percentage for the conditions I described?

69427

You can't move weight front to rear (or vise versa) by adjusting the springs (the vehicle mass is still in the same places after the spring adjustment). You can only move the weight diagonally.

Regarding extra nose weight for better braking, consider why it's difficult to outbrake a rear heavy 911.

RedLS1GTO

You can get quite a bit of movement even with the stock bolts. This is 100% original GM suspension, and still had a little room to go:



To the OP, you aren't going to do anything in the way of F/R distribution with the ride height. You can go corner to corner with weight, but not much front to rear. Set the rake and ride height FIRST, and then if you want some fine tuning you can go corner to corner with it.

Sox-Fan

You're right, as is 69427. Well, that makes putting the car back to where it should be a lot easier then. The car previously was level. What's optimal for rake?

brkntrxn

1/2 to 5/8"

Sox-Fan

Terrific. Thank you all for the help.

acrace

OP:

On my '03 Z06, which was run in SCCA Stock class configuration (thus, factory leaf spring adjusters, not longer bolts or cut bushings) and good enough to finish in the trophies at the national championships, my weights were 54.5% front/45.5% rear. I was able to achieve cross weights within two pounds. Measurements taken using the autocross tires and 1/8th tank of gas.

Frame-to-ground measurements were approx 5-1/4" front and 5-3/4" rear - taken from the tie down location to the ground.

Sox-Fan

Thank you. I'm also stock.

0Anthony @ LGMotorsports

You can't move it right to left either...

Sox-Fan

I could go on a diet!