sjcbristol

Hi everyone, new to the community. Owner of a 993 manual coupe C4. Is a suspension upgrade a worthwhile investment? how much better are the drive characteristics?

Thanks

Steve

Endoman

There is such a wide range to choose from it depends what you use the car for amd condition of current sysytem. Generally speaking Koni FSD for normal driving. Bilstien PSS10s or Ohlins for occasional track use.
Best to get an overall evaluation of current setup by a good shop and if all is good a full geo.When I first got my car a front shock had gone and a rear wishbone bush was toast. Went for Bilstein HD's set at Euro sport height, didn't like it a bit harsh and unpredictable.
Now running PSS10s full RS suspension components and RS ride height. A very different car, handles a dream if still a bit firm. Best value was the eventual full geo done by the UK experts at Center of Gravity.

sjcbristol

Thanks, I am not looking for track use, just trips to Europe. Drove to the Italian lakes last year and had a great time but felt the suspension was a little too firm. I think the Koni’s are worth a look. Thanks for the advice. Steve

rk-d

I have Koni Special Actives. Ride is definitely compliant, but it's a very good performing shock. Certainly more than enough for street driving. I'd probably want something more aggressive if I was driving on a track.

Endoman

A nice write up and comparison here I agree with all his comments.
http://www.911uk.com/viewtopic.php?p=712857

993c4_Toronto

Thanks for that link. It is a great write up.

Tlaloc75

It’s too bad he didn’t try PSS10 in his writeup. I agree that HDs are crashy - that’s what I thought too. The PSS10 are a world better because of their digressive valving. The koni’s are not as harsh as HDs but in my opinion the damping doesn’t feel as sophisticated - I believe they are a linear stack.

Suspension is hard because it is so subjective, it’s hard to know what you will like. It’s expensive, and very hard to try before you buy - unless you have a lot of friends with a lot of suspension variations to test drive.

In my opinion, based on what I’ve driven, and what I’ve read over years of research, it is very hard to go wrong with a proven coilover, such as PSS10 or KW v3, unless you are really focused on comfort over performance. The adjustability allows you to dial things in to your preference, which is nice.

Don’t forget to pay attention to your bushings too, the shocks are just one aspect of your suspension.

rk-d

FWIW I would have gone w/PSS10, but was having to make other expensive updates to the suspension/steering and total cost was an issue. The Konis are probably the most cost effective solution.

I think your last point is important, because there is more to the suspension than just the shocks. These cars are old and it's a foregone conclusion that a number of suspension components need to be replaced over time for peak performance.

sjcbristol

Great link, thank you. Koni’s sound the right choice for road use.

Andrew B

I went ahead and purchased Koni FSDs after reading this same link. I wanted mine set up for spirited road use and the blurb made sense to me and felt they were everything I was longing for. Once they were installed with the standard springs (per sellers advice) and the car had been aligned I really wasn't wowed at all. Sure, they were new shocks so the car rode and responded better but they were crashy on bumps and it wouldn't hold a nice position in turns. I've driven nice cars all my life and this setup was nothing to write home about in any sense, after 5000 miles on them I was completely underwhelmed and decided to go in a different direction. In my opinion FSDs are a "you get what you pay for" deal.

From there I narrowed my choice was between PSS10s and Ohlins Road and Track. Living in Sonoma CA there was a local Öhlins dealer who was able to make a kit that suited my needs so I went in that direction. They also spoke my language, explaining how good shock absorbers were made with quality components and precision valving and preaching that good suspension in prose and compliance, they were able to check the valves in each shock to make sure they had equal specs, install a spring rate to suit my needs and adjust valves to match. What is interesting is if you read the website blurb for the valving in Öhlins Road and track and the Koni FSDs is that they both tell you that they are achieving the same thing (albeit the diagrams and methods are different. So, in the end my setup was Ohlins road and track shocks, with slightly softer springs and stock rubber mounts. The result is magnificent!!! The car can hold a line in a corner with extreme confidence and it sucks up every bump. When friends ride in the car they comment on how smoothly it rides saying it's like a new car. One friend in particular who has an Audi RS5 was blown away in terms of handling and compliance and after driving his RS5 I understand why.

I can't speak to PSS10s, but, in a direct comparison on the same car, FSDs were a waste of money and the Öhlins Road and track showed me how a true sports car should handle. And, the Öhlins are way more comfortable in EVERY situation.

We've all paid good money for the cars and quality suspensions gets the most out of them

Meatball964

Not sure the PSS10's are a fair comparison to Ohlin R & T's which are twice as much $ (when you add in mounting plates/hardware).
PSS10's come complete & use OEM perches etc. Unless your dealer is pricing them at the $2500 mark, I would put the Ohlins in the MCS/Moton/JRZ
catagory. The Ohlins are on my wish list (for my 964) to replace my Bilstein HD's. Just not sure I want to take the leap $....

nine9six

KW V3, is a nice suspension pkg., and also worth considering.

Andrew B

I used the stock mounts for compliance, to reduce NVH and for longer life. And, it kept the cost down too.

inkatouring

There are almost as many choices for suspensions as there are colors in the 993 pallet. Here is a link for several of the more popular choices. As you can tell, it is a knowledgeable supplier in Europe, too. Personally, I went with Koni sport and RoW M030 because I wanted a slightly sportier, lower, and adjustable suspension. It is the second 993 I've had with this setup; never would have bought it originally as I've always been a Bilstein guy but it was on my first c4s and I loved it. Several here have criticized Bilsteins as too harsh -- and since suspension is subjective, I prefer Koni's adjustability.

Hidden in the cost of suspensions -- at least if you change the springs -- is a four-wheel alignment, which isn't cheap. Don't forget that!

Good luck!

Bill Verburg

stock most Bilstein will be on the harsh side, the main reason is the old style linear valve stack and secondarily sometimes a mismatch between spring rates and valving(this later depends on the springs used and chassis weight w/ people using anything from stockish 200 lb/in to race ready 1000 lb/in springs w/ the same shock and anywhere from 2400 to 3200# chassis)

You do have a relatively inexpensive option for b6 & b8 shocks, I did this to my Cup shocks right out of the box, have them revalved w/ a digressive valve stack tuned to the springs, chassis weight and use. The difference is night and day and compares well to the latest Moton/Motion Control/JRZ etc offerings except that you don't get to have the fun of fiddling w/ the various settings. Fiddling at the race track is probably the best way to get 10/10ths from any shock but for street use it's just not necessary.

It appears to me that the Koni FSD is a variation of a digressive valve stack, Moton/Motion control et al all come w/ digressive or more exotic valving stock as do PSS shocks, others are less open about thein designs.

what ever shock you use do not skimp on the bushings, the sport rubber used by 993 RS in the front A-arms and rear KT & A-arms makes a huge difference in how the car behaves. You can go much further but at least emulate the RS bushes.