Does the 996TT have adjustable castor and what is the factory setting.

TIA,

Mark

 

I dont believe so. I believe the only way to adjust caster is to get adjustable thrust arm bushings.

 

Hi, You need GT2 lower control arm(2 parts) with adjustable arm bushing and shims to get your camber right
Tim

 

Certainly.

Factory settings: 8 deg +/- 30 minutes
Maximum difference left to right: 40'

You can change these settings as needed, but go to someone who knows what they are doing, it cannot be done in isolation, it should be done in conjunction with other settings overall. for street driving, no need to touch anything.

 

Thanks Jean.

 

My indy shop recently lowered my car, installed PSS9's, did a corner balance and an alignment, and now the car drifts to the left a little. I took it back to them and they tweaked it, but it still drifts left a little. They say it is because there is a 30 degree difference in stock castor setting, that can only be changed by going to the upgraded control arms. I never noticed this left drift until they worked on the car, or maybe I never paid any attention to it until after they did the suspension work. Does their explanation ring true to you guys? Any suggestions? How much $$ for the upgraded control arms?

 

Cup arms run about $600 a piece.

 

rosesplus, welcome.

landjet, that is very unlikely the reason ( I am guessing you are saying 30minutes, not degrees?)
Care to share the readings of your setup, looks to me that you have too much castor, or too little.

 

Looking at my readout, I don't see where there is 30 minutes difference, so now I don't know what they can be talking about. But then, this readout is all Greek to me. Here is what it says: front left-camber.57,caster.8.32, toe.02, front right-camber.63, caster8.24, toe.03, front cross camber.06, cross caster.08, total toe.05. Left rear- camber1.42, toe.17, right rear- camber1.50, toe.18, total toe.35, thrust angle.00. I requested that these settings be set at stock specs, as I wanted a good street ride and don't know enough about track use to be messing with that aspect until I get some more experience. What do these settings tell you? Why would the car be drifting left?

 

landjet, these settings are good.

The next question to ask is what are your corner weights Front right, left and rear right and left. The most likely explanation is that they might screwed up ride height and corner balance. I would bet this is the problem.

Somewhat stupid question but have you checked your tire pressures?

Do you have any problems with sticky brakes?

 

Jean, thanks for taking the time to check this out. BTW, love your car.
I don't believe I have sticking brakes as the car only has11,000 miles and has only been driven in the rain twice, and I don't feel any issues with braking. The corner balance figures are: front left 752, front right 714, left rear 1179, right rear 1085. This is considering a 200 pound driver. My tire pressures are 36 for both fronts and 41 for both rears. The rears need some air.
If the corner balance needs to be redone, does that mean I will need another alignment?

 

landsjet

Your left total weight is about 140lbs more than the right side. This means that it will impact your car to pull towards the left. However normally this would not be enough to be very noticeable, especially since the cross weight is fine. But if you add this to a few other imperfections, then a 140lbs can make a difference yes.

I am assuming that the tire pressures that you mentioned are as measured while the car is drifting.

I am also assuming your tire tread is properly worn out.

Other than that , difficult to know, what is going on without looking at the car. The shop HAS to fix it, the castor story and stock arms is BS.

 

Jean, the tires are almost new, maybe 1500 miles on a set of MPS2's, and the tire pressure has not been changed since I got it back from the shop. The roads here are covered in salt at the moment so I won't be driving it again until we get some good rain. Thanks for your time.