New C4 springs and dampers

[andythompson]

Hi,
My 964 C4 needs new springs and dampers. Jaz Porsche are advising Bilstein suspension with Eibach pro lowering spring kit. However, Centre Gravity are advising Koni FSD with new OEM bump stops, top mounts and Eibach springs.
Are there pro and cons for the Bilsteins vs the Koni FSDs? I use the car mainly on UK A and B roads. No track use.
I'd appreciate any other advice or experience....

 

[polar964]

Hi Andy,
I had my suspension done by Chris at Center-gravity a number of years back now. At the time Chris recommended Bilsteins with Porsche own M030 springs and power-flex bushes for the wishbones.
Products move on and new ones are introduced, also each customers preferences and requirements are different. Chris will evaluate in a personal and individual basis. Would have thought Chris would be proposing your best option given your requirement and budget.

 

[colin129]

Might be some useful stuff here:

https://www.porscheclubgb../forum/tm.aspx?m=922475

 

[Steve Brookes]

Go KWV1 for a good fast road set up. Less cost than KWV3 but you don't need the adjustability of the V3 as you're not tracking it. Springs and shocks are matched so you don't need to worry about buying them separately.

I'm surprised by the Koni option but Chris certainly knows his stuff so there must be a reason. Maybe ask him how many 964s he's already fitted it to? I would hope an expert like Chris has not been swayed into recommending a product because it's a good deal for him.

 

[924Srr27l]

Koni FSD is a Mechanical Damper which acts like some Electronic ones do, they have a trick (Patented) Valve system for
slow and fast speed compression which means you'll get a far better decent ride quality than a Sport shock like Koni's Sport range or Bilstein etc

When I worked for Koni the FSD had just come out (2005) and they were marketed to be used with standard ride height springs, and not lowered
Because lowering the piston rod puts it in the harder zone, and not the comfort position. Harder Compression (Cornering) the valve tightens the stiffness and control etc...

Maybe this has changed since then and Chris will no doubt of experienced these effects to of recommended this set up for you?

There is too much marketing and Emphasis on "Track" and Race suspension (Which sells units) for cars that are used on the road. It's a chalk and cheese scenario in my opinion.

I've lost 250kg from a 924S and I now need to have Shock valving and Spring rates made to spec to suit the car's low weight, because all the uprated suspension offered by all the popular suppliers is way too stiff for my Road Car! as it's been designed to make 1.5 ton cars stiff as a board and
this on my 1 ton car is horrifically too stiff for UK roads!

I'm hoping to have a Dutch Company do this for me early next year (Intrax)

Roger

 

[Dekker]

The Koni's are only for the post '92 cars, I've never met anyone who's fitted them to a 964 yet.

 

[924Srr27l]

The Koni's are only for the post '92 cars, I've never met anyone who's fitted them to a 964 yet.

They could be really good, here's some more technical details:

Fits:
Porsche 911 (964) C2 / C4 Coupé, Targa & Convertible 01.1991-09.1993 (later type cars)
Porsche 911 (964) Turbo (S) 08.1990-09.1993

FSD takes body control to the next level

The first shock absorber kit offering superior road-holding without compromising comfort.

KONI introduces FSD, the first no-compromise shock absorber in the world. A revolutionary new technique which combines the benefits of firm and comfortable suspension in a single perfect shock absorber. KONI introduces a shocks kit consisting of front and rear shocks. Firm for sporty driving on even road surfaces. Comfortable for a smooth ride on uneven road surfaces.

KONI FSD realizing the seemingly impossible!

Two characteristics that seemed diametrically- opposed, proved to be a source of inspiration for specialists from KONI. Following lengthy development and testing, the ultimate solution was reached: KONI FSD - Frequency Selective Damping.

A revolutionary new technique whereby the benefits of both types of ride characteristics are combined in one perfect shock absorber. Banishing the disadvantages of the past. FSD shock absorbers; a smart suspension system adjusting automatically to road conditions as well as driving style. And all of this in a fraction of a second. FSD guarantees greater stability, greater control and thus greater driving pleasure.

KONI reconfirms with the FSD innovation a leading position as innovative supplier of high-quality shock absorber products.

Advantages of FSD

• Ends the compromise between comfort and handling
• Can be integrated in conventional damper layouts
• No need for sensors, cables, or other electronic devices
• Creates an additional variable in fine-tuning the car's behaviour
• Quick and easy to develop for existing suspensions
• Damper cost efficient

 

[mhl1947]

I recently fitted a full Bilstein B16 coilover kit (PSS10) to my C4 and have been amazed at how they have transformed its ride and handling. I don't need the adjustability that the B16s provide - my driving is largely fast A/B road, no track work, like the OP - but they were available at the time as a special all-inclusive deal (top mounts, etc) and offered the most cost-effective option. I can't compare with Konis, and I'm sure the other contributors above are offering sound advice from greater experience. Just thought I'd chip in my own twopennyworth.

 

[andythompson]

Many thanks for your thoughts and feedback. I trust CG and think i'll go with their Koni FSD advice. Sounds like you don't get them fitted much to early 964 cars, so i'll report back my findings

 

[Steve Brookes]

I recently fitted a full Bilstein B16 coilover kit (PSS10) to my C4 and have been amazed at how they have transformed its ride and handling. I don't need the adjustability that the B16s provide - my driving is largely fast A/B road, no track work, like the OP - but they were available at the time as a special all-inclusive deal (top mounts, etc) and offered the most cost-effective option. I can't compare with Konis, and I'm sure the other contributors above are offering sound advice from greater experience. Just thought I'd chip in my own twopennyworth.

It's good advice because the PSS10 are great set up as you've found. They're easy to adjust and on the softer settings are great for the road. You're also in good company because Walter Rohrl has them on his 964RS.

 

[924Srr27l]

I think that's a good choice and many others owners may follow if they do what they say on the tin!

It looks like they are OK combined with lower than stock springs, I found this Yankie site:

http://www.koni-na.com/en-US/NorthAmerica/Products/Cars/STREET-PERFORMANCE/FSD-Eibach-Kit/

I look forward to hearing how you get on, for me (And many others) if you can have your cake and eat it
(Good Handling and a compliant ride quality) that's an impressive set of characteristics for an enjoyable road car that's a classic
but still good against more modern machinery.

Roger