Alignment Help

[BlackSnake]

I took my 99 in for an alignment today (it was pulling to the right). I got it back and the 'service rep' said they ran into a problem... something about them having to OVER ADJUST the left/front to make up with a problem they ran into with the right/front. Apparently, whatever setting they were trying to get it to on the front right could not be reached

You must be registered for see images

That's about as much detail he could give me. Car seems to drive fine now.

Here are the numbers on the front. Can someone tell me what these mean, or if they see any issues? Thanks!


FRONT RIGHT (The one with the problem)
--------------------------

 

[dblankenbaker]

A car will pull towards the side with more positive camber. Since the Viper runs negative camber in front, it will pull towards the side with the least negative camber.

From your specs, the LF was actually the side out of whack, unless you roadrace with Hoosiers or slicks and run -2.0 camber in front.

The problem is that they could only get about 4.9 degrees positive CASTER in the front. This should be 6.0. More positive caster helps the steering wheel return to center.

I am betting that your sport shims have been pulled. Pulling the sport shims gives you an additional -1.0 degrees camber in front without affecting caster. However, without the the sport shims, you lose the ability to adjust your alignment in the front back down close to zero camber while maintaining 6.0 degrees positive caster.

If you are indeed "at the limits", you can get to 6.0 positive caster by adjusting the rear cams outward (lobe towards the inside). This one adjustment will give you more negative camber and more positive caster at the same time. You will need to check toe after making this change.

BTW, **TOE** is the other clue that your sport shims have been pulled. The degree of toe-out in your 'before' numbers indicates this. Sport shims were pulled, and toe was never reset.

Your alignment is fine for street driving. I think the early cars ('92-'93) were even set at the factory for only 5.0 CASTER in the front.

You'd definitely want more negative camber in front for auto-x. Like I said: Dial in more negative camber, and caster will get to where you want it to be.

Just my $0.02 (based on 20 years doing my own alignments in my garage).

Dave

 

[BlackSnake]

Thanks for the reply. The problem is I bought the car 'new' from a dealer in Galveston; however, the dealer owner put 500 miles on it before they put it on the lot for sale. I got it for a song so that was fine with me.... Who knows, maybe he had the shims removed.

Does anyone have a PICTURE of what the sport shims look like when they are in place (or when not in place) so I can verify...

Thanks!

 

[GTS Dean]

The caster is still out of spec. If the sport shims are in place, there should be no reason (other than frame damage or worn bushings) why the recommended 6 degree setting cannot be reached with the camber in spec.

If you want your car to turn crisply and are not terribly worried about tire wear, I recommend between -1.0 and -1.2 degrees camber up front and about -0.9 out back. However, since nobody but the dealer will have any way of checking caster at the rear, I would recommend leaving it alone. The worst thing you can have is very unequal caster settings at the rear. It makes for unsettling and highly unpredictable behavior during power-down through and out of corners.

I drove a friend's '99 GTS at TWS last fall. It was way squirrely in the corners and unbalanced. We checked the rear caster and one side was at +0.9 (OK), the other was at -0.6 (SERIOUSLY BAD). The camber was within 1/4 deg. side-to-side and the toe was fine.