My car was feeling a little floaty at higher speeds so I decided to check my rake and do a little lowering on the stock bolts. When I checked the rake it was slightly lower in the back when measuring at the Jack puck holes.

When I checked the lowering bolts the rears were all the way down (1 thread showing,) the passenger front was all the way down, and the driver's front bolt was about 5 threads higher than the passenger side. The only reason I can think why the previous owner might have done this is for a possible drag racing setup.

I now have the two front bolts 1/4 turn from all the way down and the rears with 5 threads showing. This is getting me about 1/4" lower in the front when measuring from the jack puck holes. But when I measure from the ground to the top of the wheel wells the fronts are about 27-3/8" from the ground and the rears are 28-5/8" thats 1-1/4" difference. That doesn't seem right to me.

Does this make any sense? Is there a more definitive and correct place to measure to get proper rake? I'm at a bit of a loss on what to do next.

Edit: I'm thinking GM might have made the rear wheel well slightly larger than the front to accomodate the larger rear wheels. This is just a guess: If they increased the radius 1/2" then my difference front to rear at the wheel wells would only be 3/4" on a level plane which doesn't seem so bad, but I'm just guessing. Maybe I'll drop the rear bolts down 1 turn.

 

I have not messed with lowering mine yet. Did you perform a search here? Iv'e seen tons of postings about lowering Z'S. Good luck,

 

Yea I did some searching on this, and most of the info I found was in C5 Tech. In some postings they measured at the wheel wells, and others they were measuring at the jack puck holes. But suggested rake varied by 1/4" at the puck holes depending on the post. So I thought I'd ask here from people with Z06 specific experience, many of whom track thier cars and have significant knowledge on this subject. Thanks for the suggestion though

 

Please post on the roadrace and autocross forum for better answers to your question.

 

I'm not sure from your description of how you've got the bolts adjusted but, here's a rule of thumb. The more threads exposed on top the spring in the front, the lower the car will be in front. However, the less threads you have showing on the rear bolts up top the lower the rear will be. The bolts work opposite of each other. Also, the wheel well readings will have lower heights in front than the rear. You can use those measurements to compare from your original heights, but to check for rake you have to measure at rocker panels. I use a 24" level and make sure the car is slightly sloping down towards the front. It's also handy for changing the oil. The engine drains better when the front is lower than the rear.

 

Thanks,

Yep I got a handle on how the bolts adjust. Great Idea with using a level though; I'll use my four footer