I had my alignment done last week and all i got was 6.37 and 6.27 degrees caster, Camber is 2.3 and 2.08 degrees.

Has anybody had this low of caster?

And if so have you adjusted the stock caster on the control arm?

How do you change it? do i have to remove the control arm?

Any help would be great.

 

The Caster angles do seem low, you should have as close to 8.0 degrees as you can get this wil improve straight line stability and make the car turn in much better.

With more than 2 degrees of camber you should use the forward most hole on the lower control arm. With the suspension relaxed (car jacked up using the jacking point on the body) there is no need to remove the lower arm.

There should also be less cross camber, I think that 0.23 degrees difference is too much. It should be as close to identical as possible.

 

Z06 - what method did you use to get neg 2 camber? Shims would have increased caster.

 

By the way, Racerron is a Porsche Racer/Guru in these parts and the only guy I would trust to align my car. I infected him with the GT3 disease by lending him mine for a track session. His wife may feel that this is the automotive equivalent of spreading HIV .. Ron doesn't think so.

Welcome to the Forum Ron!

 

Z06:

I had mine done last week, by adding 7mm shims.

I got 2.5 degrees camber at all wheels (not the exact measure, I don't have the print out here), and my caster is L8.8 and R9.0.


Did you rotate the upper mount or you went for shims?

 

I extended the holes on top with a die grinder.
Shims should be stock.

I sent Racerron an email.

 

NJ-GT,

Did you feel any difference with the steering? .......i would assume it increased caster over stock.
On my car the steering is like a grocery kart, over light bumps the steering moves left to right, not very stable, have not tracked it yet.

 

NJ-GT my caster is also right around the 9 since doing the full corner weight, -2.3ºf -2.5ºr, but the car feels like it's on rails, and is really great at the track, so I have no issue with it in terms of feel and feedback.

Of course I'm a little concerned that it's out, as there is no easy adjustment for it. When I posted about it a couple of months ago I wasn't able to arrive at a solid conclusion as to wether I was doing any serious damage, and should try to change it. There was a point raised about the possible fouling of a rubber bushing in the linkage, but fixing it would mean another day at the aligners, and it seemed a lot of extra time and work for something that could be just fine, so I've just left it for the moment.

 

Z06:

I've zero toe at the front. My caster was increased over stock with the new alignment.

The steering feel is GREAT. Turn in is crisp and precise. I ran an autocross last Sunday in a very bumpy lot on street tires, and steering was excellent. No understeer at all. Instead the car oversteers under full power (of course!), but car can't be more neutral than this.

You extended the holes? OMG!!!

Macfly:

If it's not broken don't fix it.

 

Unless i misunderstood Bob, he recommended i extend the tops.
I have a slight push, handling is great overall, with throttle i can rotate it, on the front i have slight toe in +3 & +5.

 

NJ-GT Yep I extended the holes on my GT2 and on My GT3 and my Boxter S previously. No issues. Z06 I don't understand how the caster changed Do you have a before nd after print out? Mine did not change and I am around 8 deg. Ovalizing does not change the caster whereas using the shims does. Myhwife's car has the shims and she also has 8,8 deg caster and minor rubbing at full lock. This is pretty weird.

I wonder if your caster adjuster on the control arm is in the wrong hole? The second hole is put there to *reduce* caster when you use shims to get negative camber. If yours is in the "less caster" position that would explain the problem. I reiterate on my Box S, GT2 and GT3 ovalizing the camber adjustment holes a little more did not, repeat not change the caster.

 

Bob is correct in saying that moving the top of the shock further in will NOT affect the caster angle whereas install shims on the lower control arm will. This is a function of the fixed length diagonal track rod attached to the middle of the lower control arm.
I saw somewhere a different track rod that had a turn buckle in the middle of it to facilitate easy caster adjustment.
Personally I think the cars should have this as standard but it may be a motorsport part only.

 

Bob:

I did get very minor rubbing on my car on the MPS2. Rubbing dissapeared when I switched to MPSC.

 

Hi Z06,

What do the figures +3 and +5 for toe mean....3 and 5 degrees I would assume but then....we all know what ***-u-me spells. ~