Hello all,
First let me start off with I've been looking through the site allot and have found allot of great info on the PSS9 but havent exactly found just what I am looking for... So, if I've missed something my apologies for the repost..

I recently purchased a Pss9 setup off of another C4. Can anyone give me some guidance on a good aggressive street setup? I track the car 1-2 times a year and use it just for fun on the street otherwise (about 5k miles year) so ride quality isnt too important. I really just dont want to screw up on the ride height to avoid repeated alignments..

Any suggestions on ride height/alignment specs on a 996 C4?

 

I would def install H&R arm (anti roll bars)... pref with adjustable drop links. Set the arm in the middle setting up front and most aggressive setting at the rear (closest to the rear). As for setting pss9, dial in 1f/1r.... this is my setup at the track and I love it on the street as well. As for ride height... thats a personal choice but... depending on your wheel setup...from the ground to the bottom of the wheel wells... @25.25"f and 25.5"r... GL

 

Excellent, thanks.. I am just running on the stock 18" wheels. As for the height, I may go a tad higher than that but not much. Hearing what other people have their height at is good, I really didnt want to do to much trial and error there for obvious reasons..

Thanks again

 

Ok, first off, this can be as complex as you want it to be. Most folks simply put on the PSS9/10 (or whatever), set it, and forget it. But, if you want some extra info, here it is. Keep in mind I don't have all the answers, some of this may be total BS and completely worthless/wrong for your car and your situation. But, here it is anyway:

With respect to your first question: when you put on the PSS9, you will drop the ride height about an inch from stock already. I seem to recall that this is due to the parts themselves as well as droop (explained shortly). Then you have about ~20mm of adjustment in the front, and ~10mm in the back (check the spec from Bilstein for your car, but it's close to 20/10). But, this needs to be taken in context:

For our cars, the PSS9 shock has about 85mm of total travel available. Of this, about 50mm is free travel before it reaches the internal bumpstops. The bumpstops can then can compress about 50mm, giving you a total MAX of about 100mm of shock travel [a little less than 4"]. Why 85mm if the numbers calculate out to 100mm? Well, in use, the internal bumpstop stiffness becomes REALLY high - effectively becoming a solid mount - at around 35mm of compression. So you have an effective operating range of about 85mm, or about 3.35". Well, what does all this mean?

With the car resting on the ground, the shock will compress simply do to the weight of the car, i.e., droop. It could be 10mm, but might be as high as 30mm [or so] based on your car weight [I don't have these numbers, but I might test on my car later tonight].

So, if you only have 85mm for shock travel, and 30mm is taken up with droop, you get about 20mm of free travel, and 35 of bumpstop travel. 55mm = ~2" of shock travel before you have "no shock" left. On some heavier cars (like the GT2, the weight of the car causes about 50mm of droop, meaning you are ALREADY on the bumpstops! YIKES!] What about simply getting heavier springs so the car doesn't droop? Well, you would have to revalve your shocks to accomodate the springs. It CAN be done though.

Another issue you face with the PSS9 system is that adjusting the ride height [any lower] also reduces the PSS9 shock travel distance [as well as preloading the springs]. Using the above example, say you use all of your 20mm adjustment range for the PSS9. Well, you would further reduce your 55mm of shock travel to 35mm (about 1.4"). On virtually any thing but the smoothest roads, 1.4" is not enough shock travel. You WILL feel it, and NOT like it. If you have less droop, you can lower the ride more, but you won't know you've gone too far until you hit that big bump that really jolts the car.

The good news is, there IS a happy lowered place where you can get optimal suspension travel without compressing to the bumpstops, but you will need to figure that out based on your car weight and track/road conditions. I had mine lowered about 15mm, but then had to raise them back up 10mm to get it off the bumpstops when at the track.

Bored yet? lol. WRT your alignment, your shop will have decent settings for your car, simply add a little more negative camber and maybe a very litte more toe. I wouldn't change caster or you will end up eating your fender wells. You could even ask them to use GT2/3 settings and simply back just a bit for your car. Should work out In any event, I would suggest nothing more than -2.0 to -2.5 degrees of camber in rear, otherwise you will be eating through your street tires pretty quickly.

Lastly, if you get the car all situated and aligned, and THEN realize you are riding the bumpstops, you can raise it up just a bit without really needing to realign it. I forget the amount, but 10mmF/5mmR should be fine. This will simply take out some negative camber and shouldn't screw up the hangling.

I hope this mess is factually accurate and helps, lol.

-td

 

More good info, thanks for the insight. As I mentioned previously, I've heard and read so many different opinions on the subject that it makes it a real chore to put it all together.

That's good info about the 10mmF/5mmR wiggle room. In the end I know I'm going to be fiddling with it for a while but now I think I have a good baseline to start off with. I've been riding this car on the stock setup for 5 years now so it's time for a change. I've heard allot of chatter about the GT2 Street specs (which I believe is very close or exactly the height RedRidge mentioned above) and am considering that..

 

So just to be clear, if you have the locking rings screwed all the way to the top, you will still result in about 1 inch less height than stock and have maximum travel...correct?

 

As I understand it, you will get ~1" drop, but your car's weight will compress the suspension a little taking away some of the shock travel. Perhaps someone can confirm this with data though.

-td

 

Well, yes, that makes sense, travel is total movement up & down, so if droop robs you of an inch (same or less, due to stiffer springs, as whatever stock is), and you have 3" down travel you have 1 inch up travel. What I actually was looking for is if it is required to actually screw the rings to the top, or if there is some intermediate position that is the same as full up. I doubt it but tought I'd ask.