NewFoundPower

I've been doing a lot of reading about handling and how ride height and rake angle affect it, so I wanted to see if there's a way I can measure how much my car has been lowered and what the rake angle currently is compared to stock and what is optimum for the track. It was lowered when I bought it but the previous owner was doing it more for looks than performance. Is there a known point on the body that I can measure from? I'm not running stock tire sizes either so I know that will affect it - does that eliminate meaasuring wheel well gap?

Thanks!
-Josh

LDB C5

I would try measuring from the ground to the underside of the fender. Compare your measurements with a stock car. As far as the optimum height / rake ange for the track, you might try posting in the autocross section.

AU N EGL

The fenders are not equal. SO not really a good place to measure

Simplest way is to measure by the jacking puck holes on the frame.

Just in front of the front jacking puke hole and just behind the rear jacking puke hole.

The BEST way is to measure is where the lower control arms meet the frame

Good Luck

leadfoot4

Not only is it the best, it's where the factory takes it's "ride height" measurements. In all honesty, I doubt that any two 'Vettes that you'd happen upon are the same ride height from the factory, so comparing your car to another would only give you a rough estimate.

NewFoundPower

Well that sounds like it's the right starting point. Is there somewhere I can find numbers for the factory ride height tolerances at those locations? I'm not so much concerned about the actual amount it's been lowered as I am the rake angle - I want to be sure that's at a good number for my current setup.

AU N EGL

Rake angle should be between 1/2" to 3/4" between those two points.

Now remember to measure with YOUR BODY WT in the drivers seat. So if you weight 200 lbs, put 200 lbs of something in the drivers seat. then measue to the frame points.

royski

NewFoundPower

Thanks guys! There are two points where the control arm mounts to the frame, right? Does it matter if it's measured at the front or rear point, or should both be checked?

leadfoot4

I measure both the front and rear, as well as both sides, front and rear, to insure the car is also level side to side.

BitViper

I'm an idiot..but I gotta ask...

Wouldn't the changes 200lbs in or out of the car be relative...assuming that all you were interested in was rake?

I understand if you were trying to hit a specific ride height, (measured at any location), say 5in up from so your looking for 5.5 - 5.75 in the rear, placing weight in the car becomes an important thing. Is this akin to corner balancing/corner weighting?

Again...I know nothing and bow and am in awe to all who know more

AU N EGL

No you not an idiot and that is a great question.

Ok my car with 200 lbs of me in drivers seat ( or 200 lbs of old brake rotors) I have the GM T1 suppension all the way UP. and run 18x12 with 18x305/30 fronts and 18x13 with 18x335/30 rear

Measured to the frame:
front, just in front of jacking puck holes

LF 3 5/8" RF 3 5/8"

and just behind the rear jacking puck holes
LR 3 7/8" RR 3 7/8"

without my wt in the seat

LF 3 6/8" RF 3 7/16"
LR 3 15/16" RR 3 7/8" with out me in the drivers seat.

my left front is 1/8" higher
Left Rear is 1/16" higher

dont have my LCA measurements or corner wt numbers handy.

Not quite corner balancing

Cornerbalaings

RF+LR = LF+RR
and that is with drivers wt and fuel in car

it is seldom exact but very close.


Does this all make a differnce? Once your car is properly aligned and corner balance, it will feel like a whole new car, and handle even better then you think it does now.


our C5 Vert is stock and

5 1/2" and 5 3/4"

Bill Dearborn

Here are the factory ride height measurements at the frame points mentioned above:

Trim Height Specifications
J Height============================K Height
Shipped====Curb================Shipped=====Curb
153mm ==== 150mm ± 6.4mm ======= 157mm ====151mm ± 6.4mm



Bill

voda1

Race cars are scaled and aligned with the drivers weight. Additionally the fuel load has to be taken into consideration. Street/passenger cars have specs given for no driver aboard.