Disclaimer: I'm not a PSS9 owner... yet, but I've done some research.

According to a Bilstein representative the softest setting on the PSS9 (setting 9) is approximately 7% stiffer than the stock 993 suspension. However, the Bilstein damper quality is much better than the factory Monroe shocks and I've heard more than one owner report that the quality of the ride actually improves with the PSS9 setup due to the more advanced shock design.

Also, I believe that the PSS9's smaller spring's sole purpose is to prevent the entire coilover assembly from becoming completely disengaged from the strut tower at maximum extension. I don't think it has any bearing on normal ride quality... it's a true "tender spring."

Hope this helps.

 

Poon,
I'm presently running PSS-9 coilovers, and RS swaybars, still experimenting with different settings for street/track/autocross. I wouldn't dismiss the PSS-9 setup out of hand just because of your mechanics recommendation. Is there any way you can get a ride in a car with the Bilsteins? I don't think you would find the ride too harsh.

The only objection I have to the setup is on the freeway using the softer damping settings (higher numbers) the front end can get to feel like it is floating along. I think it is a matter of the spacing of the expansion joints here, maybe they hit a resonant frequency with the springs/shocks.

The adjustment ***** are a bit harder to get to on the Bilsteins, the fronts are on the very bottom of the tube, covered by a soft plastic cap, the rears are near the bottom on the side of the tube. You can adjust the dampers with the wheels mounted, kind of tricky, using a mirror and flashlight.

 

Hi Ben:

If I may step in here a moment and add something here,....

Dampers perform many roles and John is right on. One of the things they control is the RATE of wheel movement and this affects transient directional changes, as well as how each wheel reacts to road irregularites.

Damper valving really has the major effect on ride quality as long as the spring package is close. In the case of the 993 PSS-9, its very good for what it was intended for; aggressive street use and track days.

Bilstein uses active tender springs and although they might look coilbound at rest when you observe them, they play a large role in the overall spring package and wheel rates with the car in motion.

 

Thank you to all for your input so far, I am still very interested in the PSS-9's as they are adjustable and I can play around with settings, from what I can see from your replies the softest setting shouldn't be too much harsher than stock and I have lived with harder. Interesting to read that the sway bars also harden up the ride quality, obviously I still have lots to learn on the suspension side.

This area is a bigger minefield than I realised. Will speak to Jonas at JZ again.

Anymore feedback appreciated.

By the way if anyone in the london/South of England with PSS-9s can take me for a spin to experience them I would appreciate it.

Thanks again

 

I'd to add that at 8f/6r, despite the stiffness, the pss9 is very quiet and to me, it gives an overall high quality ride, much better than stock's.

I also agree that at softest, it's very close to stock setup and again, very quiet.

 

Just to add another variable:

In my opinion a very good suspension "upgrade" is a good set of aftermarket wheels. You can save 10 lbs per wheel of unsprung weight, and that lower intertia allows the suspension to react much more quickly and keep the tires in solid contact with the road, which is pretty much the point of suspension in the first place.

 

Steve,

Thanks for the clarification.

You also stated

And this is exactly my clumsy point. That's the type of 993 driver I am and if that's what Poon is after I suspect he can't do much better!

But I think some folks are convinced PSS-9 is always the best upgrade - and that's not necessarily the case. I know when I was deciding on my upgrade choice I was strongly directed to the PSS-9 and it's 'better than stock' ride quality. If one were to infer a more (gasp) luxurious ride - or even Cadillac like - from that guidance dissappointment would be at hand!

Just trying to add some perspective - and remember, I'm a satisfied user of this very system!

Ben

 

As a reference point on spring rates, the 993RS has progressive springs but Porsche quote the nominal rate as 43N/mm front and 80N/mm rear, which if my abacus is working right equates to 245lb/in front, 456lb/in rear.

I reckon that is a similar front/rear ratio to the PSS-9, but about 15% stiffer, but I can't quite bring myself to go through the PSS-9's wire and coil diameter data to work out their overall rates. A higher rear to front spring rate ratio (than stock) helps reduce understeer.

And on the general question of PSS-9, fitting them was by far the best thing I've done for the car, even when originally running PSS-9 with the stock anti-roll bars, and adding the RS bars was another big step forward.

 

Quote Steve
In the case of the 993 PSS-9, its very good for what it was intended for; aggressive street use and track days.


Quote Ben
And this is exactly my clumsy point. That's the type of 993 driver I am and if that's what Poon is after I suspect he can't do much better!

I think you have both summed up the arguement for me, I like to have an aggressive set up, and if I got a conservative ride would always be looking to change (nature of the beast). Think I'll go for the PSS-9's as it doesn't sound as though they are ridiculously hard.

 

Poon,

I have run the PSS-9's for about 6 months on both street and track, and they are great. I run softer settings on the street (8 front / 6 rear), and they are far more comfortable and compliant than my previous set-up of Eibach springs with stock shocks. On the track, I stiffen up to 2 front / 1 rear, and they are confidence inspiring, although maybe not as perfect as a true race setup.

All in all, a wonderful solution for those who track a daily driver. Have no fear!

BTW, my avatar is from before the PSS-9 upgrade. It doesn't roll that much now!

 

Thanks Anir,

Nice to hear that you had my current set-up and find the PSS-9s more comfortable.

 

Poon,
I have to agree wth Anir, the PSS-9 setup is a great compromise solution for a streetable car which is also at home on the track.

I suppose of you were aiming for a track only car there would be some suspension kit out there that would outperform the Bilsteins, but it would be too harsh for a daily driver, just blatant conjecture on my part, but sound reasoning that ultimate handling and ride comfort do not usually go hand in hand.

I'll echo Anir again in his description of the track manners of the setup as, "confidence inspiring", I don't think it can be said any better. The car tracks consistently instead of searching around for the correct set. Turn-in, set, and exit are all done with smooth transitions, it is very difficult to upset the car.

The engineers did their homework before putting this kit together, and the setup mates quite nicely with the RS sway bars. I'm ready to start a PSS-9 fan club I'm so pleased, I couldn't be much more enthusiastic even if I were selling the dang kits.

But all gushing aside, try to get a ride in cars with the suspensions you are interested in, that will take away all the fear of, "will this be too stiff/harsh", or , "this suspension doesn't feel right", before you invest money in the project.

This quote is worth reading again, take it to heart like the gospel, (and a good argument for adjustable dampers).

Best of luck finding your ideal solution.