jkb157

I have read that 95 993(PCA Web site) should have the rear suspension updated to 96 due to oversteer tendency when driving the car hard and thru a bumpy corner.Does this occur with a stock suspension setup and with a car which may have an been lowered and has upgraded shocks and sway bars?What change did porsche make to the suspension in 96 for the 993?Thanks

fast_freddy

From what I understand unless your car is seriously lowered, i.e. far beyond a set of Bilstein HD's/H&R springs bump steer is not an issue. Perhaps our friend Steve Weiner from Rennsport Systems could chime in. With me a little information is a very very dangerous thing and all I have is a little information about this. I do know that to "cure" bump steer on seriously lowered 993's is not a cheap modification, you have to change the uprights, kinematic links, subframe arch and another bit or two to the appropriate spec.

George A

I thought it was just a change in rear alignment specs? I could be wrong.

G.

TheOtherEric

jkb is right, on the pca website, Reiser tells owners of 1995 993's swap out ALL of their rear control arms and subframe for the updated 1996+ parts. Calls it "an absolute necessity for the track, and is close to that on a street driven car." It's been discussed in the past, but in short, nobody follows that advice because there's no known basis to do so. It's always peeved me for someone in his position to make such ridiculous, unsupported, and expen$ive recommendations. Would probably cost $4k for everything, installed. He really should retract that or else find a rationale for it. Yes, the part #s were changed in 1996, but it hasn't even been established that there's been a significant geometry change AFAIK. And if so, that it has a meaningful effect on handling.

Here's some reading:

https://rennlist.com/forums/993-forum/312384-1995-versus-1996-1998-a.html
https://rennlist.com/forums/993-forum/255937-95-or-96-a.html

John H

I never noticed any rear bump steer on my lowered, race prepped 95 993. Now front end bump steer, yes.

chris walrod

These will help cure that

jmreiser

Excuse me? I know of a number of cars that were crashed and totalled due to this problem. This problem and my experience with it goes back 13 years. With the first one or two, we figured it was driver error. But later the numbers increased, and a number of them were very experienced instructors. The 993 has passive rear steering. The 1994 & 1995 cars can get into a mode where it suddenly tugs back & forth on you in a high speed corner. If that happens, you are in deep trouble. Porsche also found this problem during the testing during development of the 993 Turbo. They made "minor suspension geometry changes". To me that is not so minor. They mean small distances were changed. The result is a big difference, and a great change. It is a no-brainer. Why would you risk crashing your car and spending or losing $20,000 to $40,000 instead of $2,000? I suppose if you only drive your car slowly, you may never see the problem.

The subframe and arches do not need to be changed. Please read that a little closer.

When you put even some of the new parts in, the alignment (toe) will now change. That establishes that the geometry has changed.

Lawrence_P

Subscribed!

Wreck Me Otter

Phokaioglaukos

This is new to me. Please explain what it is and how it changed with the 996s.

jmreiser

Porsche has been working more & more tricks with the rear axle suspension for some time. They started some of this with the 964. They added "kinematics" and kinematic adjustment for the 993. They had a lot of trouble helping the dealers deal with this, in addition to the issues above. For the 996 they further developed it, but took away the adjustment. Race teams can still mess with it by changing the arms.

K964

+1

38D

Two friends of mine have driven a '95 993 at the track...both described the car as "evil" above 8/10ths.

Bull

I'm with Joel, and know the people Colin mentions, who are not new to this. Many, after having similar experiences with '95s, believe it to be true of all 993s. Having owned a '96 and a '97, I can tell you it isn't.....but a poorly set-up, out of alignment (slightly) '97 can make you think you are in a '95. "Twitchy near the limit" is the usual description.

If you drive your '95 on the street, or below 8/10s on the track, then it really shouldn't matter.

George A

Which arms change in length? Shorter?? Longer??

I almost wish I would have done the full ERP rear links rather than just the bushing/monoballs after I've read this. Mine is a '96 but still....

G.