[Geo968]

I have a 92 968 that is stripped down to 2860 lbs.  It is a mostly track car, since it has sticky 10" tires and no A/C, no radio, etc.  This is my first Porsche, but I am a very good mech, and I do all my own work on my cars,  I know how to do front wheel alignment, but this is the first car I've owned that requires 4-wheel alignment, so I need some help.  i have read the service manual and understand how to do the rear wheel toe & camber adjustments. 

 

Car has a square wheel setup with 17" x 10.5" wheels, MOTON Clubsport coilovers with 550# front springs, 800# rear springs.  Car has manual steering and is lowered as much as practical.  Roll Centers were measured to be 45mm Front, 120mm Rear (obviously above the ground).  I've read everything I could find on preferred specs for this car (OEM, street, auto-X, track). 

 

When I took delivery, car was currently set up as follows, and does not handle very well - it's OK, but I expect a lot better from a Porsche 944/968.  Car is twitchy, even at street speeds (left is driver side):

 

Caster - as much as you can get (have not measured it)

Camber Front -2.5 deg on right, -4 deg on left

Camber Rear -4 deg right, -5 deg left.

Toe - 4/16" Toe OUT on Front, 5/32" Toe IN on Rear (total)

 

I changed ti to be this, and now it handles worse:

Caster - as much as you can get

Camber Front -2.5 deg

Camber Rear -2 deg

Toe - 1/6" Toe IN Front, 1/8" Toe IN Rear.(total)

Height - even front to rear

 

Everything I've read says a little Front Toe IN helps the car to be more stable at high speed, but most other cars I've driven feel more stable to me with a bit of Toe OUT in front.  Also, a little Rear Toe IN should help the car be more stable, but this car already has Toe IN and still doesn't like to go in a straight line - needs constant correction.

 

Is what I just said about Toe IN correct?

 

I want it to drive more stable and straight at high speed, I don't care if it has a little understeer.  I can tune that out with shocks and swaybars and tire pressure.

 

Ideas?   Comments?

 

Thanks,

- George -

 

 

 

 

 

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[Eric_K]

I think you might have some other issue. Those alignment settings shouldn't cause straight line instability. I would check your wheel bearings, bushings, steering rack, etc.

For the track I prefer some toe-out at the front and slight toe-in for the rear.

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