froggy47

From the factory settings to max lowered on stock adjusters, how much is there front/rear?

Don't count if you raised it UP on factory adjusters, just stock setting to max down.

Please post only if you know from experience or have access to factory data. Don't repost "I heard it was about.....".

I think I put bump steer into my front suspension (now that I know what it is). Street driving (slicks) when I go over some street irregularities/bumps the car momentarily darts left/right or maybe left & back to center or right & back to center, it's hard to tell, felt in the wheel also.

I don't notice it in autox & track but that's such a totally different set of circumstances/speed/grip I'm not sure I would notice it.

My alignment has a lot of neg but zero toe front & max lowered front. 1/4 inch rake up in back, measured at tie downs. I expect some tramlining, but this is different, not tramlining.

I should have done before/ after but did not. Still learning.

Thanks

acrace

On my '03:

LF: 15 mm
RF: 14 mm
LR: 21 mm
RR: 18 mm

I don't know if this makes a difference, but this was with a full tank of gas and no driver in the vehicle. Measurement was made at the fender lip. Car was driven for approx 5 miles to help settle things.

Bill Dearborn

Owner's Manual states lowering should be no more than 15mm. That is a lot less than what a lot of people do but I suspect GM had a good reason for putting that info in the owner's manual.

Bill

CHJ In Virginia

I took my Z down as far as it would go on the stock bushings / bolts. It brought the car down right at 3/4" all the way around. I am running a compromise alignment with 1.5 deg negative camber F & R and just a very slight bit of toe in at the front as a concession for the street driving that I do once in awhile.

96solo

I've been where you are. The front can be lowered as much as 1 3/8", but I don't recommend being that low. The rear on the stock bolts is about 3/4". To get the ride height and the car corner balanced you'll need to get lowering bolts for the rear. You need to maintain 3 threads widths left for safety in the rear.

I started with the car lowered 1" then raised the car in the two corners in the front and driver's rear until we got it very close on cross weight. Your passenger rear will be the lightest and most likely not need adjustment. You'll need to remove the bolts holding the sway bars to the control arms temporarily, so not to get a false reading on your scales. You'll need to be in the car also during this to accurately get it right. It is a trial by error approach and will take many times to get it right. Don't forget to recompress the suspension to get a true ride height each time it is adjusted. There's a procedure in the factory manuals that works very well. We got mine within 16 pounds cross weight and the car was always neutral. Good luck. This was for ASP class at that time.

davidfarmer

every car is different....most no more than 3/4" without cutting....

voda1

What is car height change per revolution of adjuster frt and rear?

96solo

Edit on mine... David is right on the front with stock bumper. For ASP, we cut half the bumper off to get 1 3/8", then later went with T-1 bumper ends.

froggy47

By bumper, you mean the adjuster bolt with the little pad on the bottom, right?

96solo

Yes, the pad the sits on the lower control arm's valley. The stock one is quite thick. The T-1 one is thin poly.

froggy47

This seems to be what my car has available in adjustment.

15mm is only a bit over 1/2 an inch.

If you LOOK at the lowering bolts, especially the fronts, and don't look at the OVERALL length, just the threads from the TOP of the pad thing to the BOTTOM of the spring I'd say you have about 3/4 inch of available threads.

Remember, at the beginning I said not to raise it UP maximum then down, just from the FACTORY SETTING down.

I don't see how anyone lowers (on stock adjusters - broken record) more than 3/4 inch at most.

Don't see how it is mechanically possible. Remember, do not count rims/tires/etc. Just the frame/suspension. I'm sure uber low profile tires will get the body down (low rider) but do not include that. Do not count modification to stock adjusters.

Does what I described driving sound like bump steer?

96solo

Bump steer can be a problem lowering below 1/2". Baer makes a nice heim joint tie rod end for that.

The way to measure the ride height is done several ways. GM calls it the J an K measurement, but many use the measurement from the lower edge of the highest part of the fender to the ground. J is measured from behind the front wheel well on the frame where the jacking hole is located (just behind it) to the ground. K is in front of the rear jacking hole in front of the rear tire well. This is used to determine rake of the car.

One other thing. When lowering the car to the 1" level, you need to check if your shock is not bottoming out. The Koni 3013 is made for the lowering on the suspension. Great bang for the buck adjustable shocks! See Sam Stanos for a matching set. Great guy! Legal in SCCA SS or ASP classes.