AVoyvoda

PSS9s seem to work well on 993s and the concensus is that that do. Mine were fitted by Autofarm, one of the top tuners in the UK, who know their stuff. I was quite amazed by how poorly they performed and tried 17 inch 7.5/9 SO2As and 18 inch 8/10 Continental wheel/tire combinations to improve the ride. Hardly any difference. I had to conclude therefore, that they are ineffective on widebody 4wd 964s. Perhaps the units were faulty, which I doubt, or my expectations are simply too high.
In any case, can't wait to get rid of them.
I have owned this car from new and drive it every day - until last year on standard ROW suspension -and had become so used to it, that I could accurately judge the level of fuel in the tank by the way it handled. Reason for changing over to PSS9s was that the car became "nose-light" at very high speeds (>120). Lowering and the PSS9s cured that, but at the cost of serious low speed discomfort. Crashing and banging over every pothole is unacceptable. There must be a better solution out there.

Tom W

What do you have the PSS-9s set at? I think they stink for street driving if at full firm, but full soft or intermediate settings is a big improvement from stock. When I got mine (a few years ago) the mechanic said that they were set at full soft - and I hated them. Luckily my forts autox was a few days later and when I went to adjust them to firm, I found that they were at full firm. The setting dial is notintuitive. I assume from your post that you've tried other settings and hate them all? What do you have them set at that leads to such unacceptable handling? You are sure that they addressed any bump-steer issues when the set the car up?

AVoyvoda

Thanks for the concern. This is not a bump steer issue or overly hard settings. On the contrary, the fact that the car can rock from side to side like a boat, shows that perhaps the settings are too soft. I think the real weakness is lack of "compliance" for the lack of a better word. The 964 in its original ROW settings was never particularly comfortable or compliant. It crashed and banged over bumps too, at low speeds, but not as much. We are not talking about unpaved strips in the middle of Africa here, but central London, where road conditions aren't too bad. On the other hand, perhaps I am expecting too much... Still, I'll test both the G8 and a custom KW set-up this summer and if they are not up to par, I'll try alternative higher-tech solutions.
Interestingly, when I mentioned this problem to another uber-tuner, he replied: "We don't like PSS9s either and are trying custom KWs which we think are far superior". So, perhaps it's not just me...

Heirsh

Did anyone ever develop the magnetic particle variable viscosity shocks? I saw a sample back in college, but nothing since then. Havent exactly looked either. Seemed like such a simple concept. apply magnet, viscosity goes up. apply more magnetic force, still higher viscosity. Extremely fast acting too, you could vary the viscosity over each section of a bump.

Sure... there are other ways, just wondering if this ever went anywhere and anyone has seen it.

doug751

PSS9 Questions:

I forgot how to set the PSS9 and my shop lost my manual. Is 9 hardest or softest?

Also, what do I line the numbers up with? There is not notch. Right now it is easy to go full tight or full loose, but in the middle, I have no idea where I am. Sure, I can get both rears the same, or get both fronts the same, but do not ask me what I am actually set at.

I could jack the car up and crank the shocks all the way clockwise or anti clockwise and figure this out, but it will save me about 30 minutes if somebody knows how to do this. Thanks!

BTW, I am set somewhere in the middle now and the car drives awsome, 100% better than stock, handles way better and the ride is great even with 17" Pliot Sport Cup 2's. The tires are awsome also and that helps.

I was told by my shop that the car sits a bit lower than ROW and that reason the cast or camber (not sure) is not perfect. The car is at full height for the PPS9 kit. Photos attached.

tonytaylor

I suspect your problem is a 964 trait. I'd agree the standard ROW suspension setup isn't the last word in compliance and gives a poor ride; At the time of it's lauch most UK road tests were unfavourable about the ride of the standard C2/C4 and gave the RS a serious kicking. Even so the standard settings can be found wanting if you want to drive harder as it is still on the soft side for track use etc. Having tried a couple of different damper/spring combinations all I'll say is that any setup that improves body control isn't going to improve the ride. The H+R coilovers I had were acceptable on the road for ride but noticably worse than the stock setup while giving a good fast road body control, albeit ultimatly inadequate on track. As far as the H+R supercup setup I now have is concerned there is no discerable "ride"; I'm contemplating rose joints all round as I can't see how it could be worse.

IMO if you want an improved "ride" I'll bet it'll be cheaper swapping for a 993 than trying to make a silk purse out of a 964. I don't think it's a simple damper/spring problem.

AVoyvoda

"IMO if you want an improved "ride" I'll bet it'll be cheaper swapping for a 993 than trying to make a silk purse out of a 964. I don't think it's a simple damper/spring problem."
You are right, of course. Overall though, I prefer the "roughness" of the 964 over the 993. Much prefer the looks too. And the quality. So, on balance, I'll stick to he 964 and if the penalty is greater low speed discomfort, well... so be it. I suspect the ride can be improved somewhat with the G8s or custom KWs. Knowledgeable people using these systems tell me they are very good. And if the ride still isn't improved, I'll try the higher-tech Ohlins.

burgass

AVoyvoda
What is your camber and toe in?

AVoyvoda

No idea, assume factory standard for widebodies with outboard suspension mounting. Would welcome suggestions.

Cupcar

It is interesting that the Bilstein on line catalog does not show a PSS9 for a 964, it does show one for a 993.

www.shox.com shows a PSS9, part number GM5 A614H2 for the 964 though.

burgass

Swaying from side to side might sometimes depend on the combination of tyres, aligment and naturaly bad roads. Tyre pressuse also. A lot of camber or or toe and stiff shocks might result in that
I would first check the angles and then try different settings on the shocks to se what happens

AVoyvoda

It's not tire pressures. Tried all sorts of combinations (with different tire widths) to no avail.
My explanation is that the PSS9s are optimised for the 993s that have completely different rear suspensions. The outboard mounting of the suspension on the 964 widebodies aggravates the situation further (all street 993s, including the turbos, have the suspension mounted inboard).
The lesson to be learnt, I think, is that PSS9s are not particularly well suited for 964s, especially at low speed. What is? Lets find out.

AVoyvoda

Decided earlier this week on an “Italian tune-up” i.e. a long high speed run. Trip: London – Nuremberg – Hamburg – London, total distance 3,002 kms mostly over high speed German autobahns. As mentioned before, car is an unmodified 964 C4 widebody, except for PSS9s and big reds. Perfect condition. 18 inch original Speedlines 8/10, Continental tires at 35 psi. The differences between ROW OEM and PSS9s are:

Low speed
OEM ROW much better. Drove through a village in Belgium and thought I’d lose my filings.

100 mph
School run. Can cruise all day long at these speeds with either setup.

120-130 mph
ROW: Front feels much too “light” at the front. Lowering, PSS9s and RS front spoilerettes have cured the front lift issue. Car feels controllable and stable. 125mph is probably the ideal cruising speed.

> 140 mph
PSS9: Car starts bouncing around quite a bit. Much depends on road surface, but being flung around violently forced me to limit top speed. 150 feels unsafe.

Conclusion:
The issue with the PSS9s remains that of compliance, evident at low and very high speeds. Must try to find a superior set-up. For normal use, OEM ROW is a better - and much cheaper - option.

Red rooster

Avoyvoda,
I wonder if the 18 inch rims are playing a part here ? I have heard that even a NB 964 on 18s rides like a brick. The lack of sidewall compliance destroys the ride on a car that rides stiff on 16 s !!

Maybe you are searching for a suspension setup that doesnt exist ??

Good luck

Geoff

AVoyvoda

Widebody 964s have exactly the same suspension settings as 964 Turbos. The 18 inch Speedlines, for example, are standard - in fact, the only - OEMs on these cars. The ride therefore, should be identical to factory standard.