Hi All,
Looking for recommendations for the PSS-9 shock settings and adjustable RS sway bars settings to use for autocross. Installed the suspension in my 1996 C4S last fall and want to get it sorted out for autocross this year. Presently the ride height is set to 993 RS specs (2" lower than stock USA)and it has an "aggressive street alignment" (-1.4 degrees front camber and -1.6 degrees rear camber) I'm running Hoosier R3S03 tires, fronts are 245/40ZR17 and rears are 315/35ZR17. Typically autocrossing on asphalt/blacktop surfaces in the Pacific Northwest,(not real hot even when it's not raining) Any advice that will help me get the car dialed in will be appreciated.
Thanks,
Jack
'96 Black C4S

Let's see I'd start the rear bar at position 1 (closest to bar) and front bar at position 3 (middle). Then set the shocks at 1/3 from full soft and tweak from there.

JC,

Thanks for the input.

Jack
'96 Black C4S

After several autocrosses and a test day I'm finally zeroing in on my autox setup.

Here's my current set-up which I'm pretty happy with. My goal is to get it to a point where all I need to do is make tire pressure changes to tune it between runs.
You'll notice I'm really trying to loosen the rear up to get the car to rotate better. Porsche did a pretty good job of taming the rear end in the 993.

- 255/40/17 Kumho Victoracer 700's all around (8" and 10" HRE's).
- Ride height is about 10mm higher than RS.
- 1.7 degrees negative camber in both front(all I can get at this height) and rear. I actually took some camber out of the rear. I used to run it with -2 degrees in the rear.
- Front Sway full soft
- Rear Sway full stiff
- Dampners set to 7 all around. Sounds soft but most of the surfaces we race on have a variety of conditions to contend with and a more compliant dampning setup can handle a wider range of surface conditions. My last suspension was too stiff for autocross.

I haven't been to the track yet but I would probably run the dampners a little firmer and the rear sway softer. I wouldn't want it as loose on the track as I do for autocross. Rotation isn't a good thing on the track.

Whatever driving style you have the PSS-9 with RS Bars gives you enough adjustability to tune your 993 to your liking. Wish I had found it 2 suspensions ago.

Buck

Instead of tuning it with tire pressures, an alternative is to tune it with rear shock adjustment. A little firmer is a little looser, a little softer is a little tighter.

DJ, the reason I don't adjust the shocks between runs is one of my two gripes with the PSS-9. The rear adjusters on my set don't have any sense of 'clicks' or indention between the settings which means you have to see the dial to get an accurate set. Seeing the adjuster with the car on the ground isn't easy. You have to use a mirror and a flashlight. The fronts are easier as they do have a click and indention that means you can do it blind (as long as you don't get confused on which way 9 and 1 are).

My other issue I've had is we couldn't get the right rear sway bar mount to stop rotating forward (clockwide) around the shock body under heavy loading. With the locking colar on top of the mount the force from the sway bar loading was rotating the mount away from the locking colar. We couldn't get the collar tight enough against the mount to withstand the force from the sway bar set full stiff. We just relocated the locking colar to under the mount. Now the force is tightening the jam effect instaed of moving away from it. Hopefully this fixes the problem.

Every PSS-9 owner should check their right rear sway bar mount on the shock to see if it's still where it was when installed. If it's loose it can go forward far enough to touch the half shaft. Mine has a nice shinny spot on it. Luckily the mount is aluminum so it didn't remove any material from the half shaft.

Buck, thanks for the inputs. I drive mine on the street everyday and have not seen the sway bar bracket loosen up yet, but I have not tried full stiff on the back sway bar yet either. When I do I will take your advice and check to make sure it doesn't rotate.

Jack
'96 Black C4S

[quote]Originally posted by Buck:
<strong>DJ, the reason I don't adjust the shocks between runs is one of my two gripes with the PSS-9. The rear adjusters on my set don't have any sense of 'clicks' or indention between the settings which means you have to see the dial to get an accurate set.</strong><hr></blockquote>

Hey Buck,

Mine had the same problem, and they were really stiff to turn. It will loosen up after a while (after turning the **** a lot). I tend to run mine on the stiff side, so I'm usually at full-stiff, or one click off of full-stiff, so that makes it a bit easier.

Let's see now, we put the bigger RS sway bar on the front and then set it to the softess setting. Could we have gotten to the same roll stiffness with the stock sway and saved some money and time?

Jack

'96 Black C4S

Jack, if you only wanted an autox setup you could probably find a non-adjustable bar (stock or 030) that would work. Being able to stiffen the front bar for the track will give you another option when tuning the car for high speed events.

My only fear about all this adjustability is all this adjustability.

Buck <img src="confused.gif" border="0">

[quote]Originally posted by Buck:
<strong>My only fear about all this adjustability is all this adjustability.
</strong><hr></blockquote>

Tell me about it. I have shocks that are adjustable for rebound and compression that totally change depending on how much nitrogen is in the canister, RS sway bars, camber plates, tire pressures, ride heights, etc that can all be adjusted. How in the world do you get the right settings? Well you just try different things and make notes of how it works, make big changes so you know if you are in the right direction. What can really mess you up is if you are compensating so much for the car doing one thing that you think it is doing another.

I am glad I didn't go with the Versa springs that allow me to change spring rates at the track.
At least there is one constant in my equation that I have to work around.

Another great way to find out how good your set up is: have a top notch driver take your ride for a few laps, they are usually able to find the limits much quicker than you are. If the car feels like it is on rails it means you are not driving hard enough.
Greg

[quote]Originally posted by Greg Fishman:
<strong> If the car feels like it is on rails it means you are not driving hard enough.
Greg</strong><hr></blockquote>


I like that one. <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" />

E. J.