Poon

Looking for some help here!

My C2 993 currently has a set of Eibach lowering springs with stock shock absorbers. The ride does not feel progressive enough under heavy cornering loads. It rolls to easily and then gives way quite violently at the rear. I have used a UK based tuner for 4 years now (previously sorted my 964) and he has diagnosed same problems with a recommendation for a Roock spring and damper set up (he is the UK agent), similar to my 964 mod.

I mentioned to him the PSS9 set up and he felt that even on the lowest setting that it would be too harsh for every day use. As far as I can see cost is roughly the same.

I do not want my fillings shaken out, however I have had very hard suspensions in the past, so one mans hard set up generally is quite soft for me. How hard are the PSS9's in relation to a fairly conservative set up such as the Roock's?

Are there any other considerations?

Stabilizers? Should I opt for bigger/adjustables. I rarely get out onto the track, but need an excuse to do so!

I will get a strut brace and have already purchased a set of RS motor mounts to reduce rear end movement (can you get these for the wife?)

Any other suggestions welcomed.

I suppose any info on your own set ups and how they work would help as it should help me make up my mind (or get more confused).

Finally I want to retain a fairly low ride height (approx 30mm loer than UK stock)

TIA

User 4621

I have to disagree with your tuner about the PSS-9's. They have much better damping circuits than stock, so even if they are set a bit firmer, they are better controlled and therefore feel plusher. On softer settings, they feel great on some of the poor road surfaces up in the mountains around here. Set firm they are great on the track with negligible body roll. Truly best of both worlds.

Good luck,

Poon

Pete

Thanks, will it be necessary to change the stabilisers? Or will the stock ones work fine given that I will not be doing too many track days.

Tom W

I second Pete's comment's on the PSS-9's. I've had them for 6 months now and love them. On the softwest setting they are similar to US stock. On the firmest setting they are nice for the track, but much firmer than I like for a daily driver.

I chose to switch to RS-sway bars because they are adjustable and can be used to reduce the understeer. They cost more and only you can decide if it is worth it to you.

User 4621

Poon,

Adjustable sway bars are nice, but not required. You can dial out the understeer with shock settings and tire pressure too. Having said that, I will go with the RS bars at some point.

Mark97c2

My setup is as follows,
*special* Euro Bilstein HD's(provided through GERT only)
US M030 springs
RS sway Bars

I chose to go through with this setup because it keeps me in stock class for SCCA.

Ben in Plano, TX

Poon,

A voice of dissention on streetability of PSS-9...

1) I have them and RS bars on 18" rims and love the setup.
2) On smooth surfaces it's a wonderful setup and not bad at all for the street.
3) As soon as the surface degrades (like where I live in North Texas on broken up concrete roads) the ride quality goes with it.

My wife (who is used to a Boxster and an Audi A4 Quattro with sport suspension) clearly indicates that it is rougher that she likes on poor road surfaces.

The spring rate in the rear is ~650 lbs! Now that's nothing for a race setup but very stiff for a street setup. If it's not bouncing and jiggling on bad roads - no problem! But give it a rough road to traverse and look out! - it'll be a bit uncomfortable.

Don't misunderstand y'all - I love it! But it is NOT a smooth ride when the roads get rough!

Ben

Macca

Hi Poon,

I have a similar set up to you currently, and like you I am very dissapointed - it has reduced my confidence in the car.

I live in NZ and I do not feel there is eniugh expertise and experience at hand to manage a PSS9 set up to my satisfaction. I have already made one costly mistake and I cannot justify $1000's spent paying for someone else to learn how to install and provision PSS9 on my car.

I have considered the full M 030 option, but frankly I do not think it represents value for money and it does not get the car as low as I would like from a visual perspective. The RS set up is too low for my liking and too expensive if genuine parts are used.

I have choosen to go with Gerts new HD shocks with M030 springs and adjustable sways. I think this is circa $1600 EURO with sway bars. It gives all of the benefits of the Bilstien set up with the more agressive bars and progressive M 030 springs. The best benefit is that Gert has had these shocks cutomised to give up to an extra 30mm of lowering through the new threads that have been machined. This means a great look, a great street set up with enough competence to handle the occassional track day....

Macca

Mark in Baltimore

I could not be any happier with my PSS-9's. On even a middle setting on urban buckboard roads, the ride quality is firm but not too harsh. Go for the PSS-9's; you will not be disappointed. The ride on my 4Runner that's equipped with load leveler air shocks inside the rear springs is much worse.

Poon

Thanks to all so far, keep em coming.

As a matter of interest how easy is it to adjust the dampers, I used to have top adj Konis on a Mk1 VW Golf (rabbit) and they were easy to do, just twist the **** on top.

Also does anyone know how the spring rates compare to the Eibachs and what the damping range is and how that compares to stock.

Help really appreciated

TIA

Christer

Poon

I don't have a 993 but have done a lot of research on the suspensions available and would like to make some comments:

1. I have H&R coilovers with RS bars on my car right now. The Roock system feels very similar to the H&R coilovers and look to me like they use the same parts. Maybe the valving of the shocks is different, maybe not. The setups certainly feel more or less identical when driving.

2. I had H&R coilovers fitted without RS bars initially. The handling was great compared to stock, reasonably comfortable but firm. I added the RS bars as well anyway, and it firmed up the car even more. Now, what I didn't realise was that the swaybars actually affected the ride quality. Before now, I thought the sway bars (anti roll bars in UK) only came into effect in turns but of course that is wrong. I love my setup, but at least you can consider this point now before deciding to buy the bars first if the setup you decide on is stiff already

Looking at the spring rates for PSS9, the setup seems A LOT stiffer. Like twice the poundage in the rear compared with H&R coilovers I believe. On paper, I would say that is going to be very stiff but of course your 993's ride a bit softer/easier than the 964 anyway so it might not be too bad.

My advice would be buy whatever you can afford. Yes, the Roock system that JZ Machtech sell is great and of good quality. No, I don't think you will need as stiff a setup as the PSS9's but if you can afford it I guess go for it, as long as you are happy with those spring rates. Ideally speaking I would drive one with PSS9's on it - I am sure someone in London area has go tthis setup already?

p.s. the Eibach progressives on the 964 start at something like 80-90lbs and go up from there depending on compression. I don't have the exact figures but they are crap IMHO and do nothing to stabilise the car during cornering. This is the cheapo way of lowering your car and should only be used for cosmetic reasons.

DC from Cape Cod

I have the PSS-9 setup and run it set at 4 on the street. I consider it to be very comfortable and not too stiff at all. It is a sports car, not a Cadillac.

Moose

Ben in Plano,
I am in the mid cities and would love to ask you some questions about your set-up. I have been undecided for quite some time. Please e-mail me so we can talk offline, would love to see your car and get a ride. Thanks.

smarusa@hbk.com

JohnM

Ben,

As the PSS-9 is a double spring setup, with the rear tender being 685 and the rear main spring 400, I reckon that would put the overall rate of the two below 400.

The main factor for ride quality is the damper setting, and at settings of 7 or above I found the result to be less damped than the stock setup, but smoother and more tolerant of poor surfaces - damper quality counts for a lot. What damper setting do you run?

Ben in Plano, TX

John,

1st let me state that I'm NOT a suspension expert (although I do play one in my own garage).

On the street in pursuit of a 'compliant' ride quality I've been all over the map in settings - including going full soft (9) all around and setting the RS bars to their softest setting.

Now it's been a loooong time since I've been in a stock 993 so my memory has faded but I think the PSS-9 at its softest is still a firmer ride. I agree that the damper setting is important - but (danger, oversimplification ahead!) it's the springs that are responsible for the quick and sharp movements, right? The dampers tend to control the larger excursions in suspension movement.

Anyway - I really like the PSS-9/RS sway setup and I'm happy I bought it. But it's difficult to convey subjective issues like 'streetability' and Rennlist always seems to focus on the performance(grip) aspect of the solution. I just wanted to add a counterweight to that tendency. IMO someone who is not taking the car to the track doesn't need the PSS-9/RS setup. A good set of lowering springs and HD Bilsteins would probably be just fine.

On the double spring setup - I've notice that once the car is on the ground the smaller spring is completely compressed on my car - so I'm not sure it's doing much other than expanding when the suspension is unloaded completely and recompressing when load returns - something that happens more often on the track than on the street, right?

Ben