1990 964 C2 suspension upgrades

porsche gt3 · 02-04-2019, 04:37 PM

Hi,

I am looking to upgrade the suspension on my 1990 964 C2. I will be driving the car mostly on the street with occasional track days. I am not looking for very stiff springs and want a ride similar to stock with enhanced handling.

I have been looking at the following:

Bilstein PSS10
Bilstein HD with H&R springs
KW v1
KW v3
H&R street performance coil over

strut tower bar (I have one)

urethane steering rack bushings

steering rack brace

993 GT2 inner tie rods

H&R adjustable sway bars

replace front control arm bushings with slightly stiffer rubber ones

leaving rear trailing arm bushings stock

replace spring plate bushings similar to stock only if bad

Please let me know your thoughts and experience with these components.

Thanks

David

spyerx · 05:38 PM

look at my build thread linked below

https://rennlist.com/forums/964-forum/904951-my-964-c2-transformation-build-thread.html

On the 964 monoballs and solid suspension components do not contribute to harshness as much as poor shock setup damping and calibration.
I've driven 964 that feel much less supple and controlled than my car that have full rubber bushings

the goal here depends your objectives.

I do not like Bilstein shocks on the 964. Never driven one or in one that didn't feel harsh and overly damped.

CarGuyoftheWest · 02-04-2019, 05:42 PM

I run mono ball upper front, the rest rubber OEM, and H&R with bigger bars. It's perfect for the street. Firm but not to stiff, drives really nice.

ian c2 · 07:10 PM

I might have a set of h&r coilovers and bars available if you’re interested ?
I’m still unpacking parts now I’m going on my 964 project , but have found one front and one rear and a pair of anti-roll-bars upto now ..
Pm me if interested and I’ll let you know what else I uncover .

IMHO , the full h&r kit is bordering on the extreme for a daily driver even using all factory rubber .
A lot more control and a better set-up than the trusted bilstein/Eibach or bilstein h&r combos , but the bars make it a little too much for my liking . ( I’m old btw )
It’s a definately improvement on bilstein/h&r 965 springs which is pretty hard to beat for a fixed-height street combo on a stock car .
Yet it offers no adjustment on the dampers for track use so ch2anging springs to the extreme is out unless you send to bilstein for revalue . *
Allthough the balance and anti-roll are adjustable , which is good as that’s more than enough to play with

*
Like lots of porsche Oem parts manufacturers , the big players in Europe all get along . (Your m-option will be eibach or h&r etc)
So h&r height-adjustable are modified bilstein dampers , and can be serviced/valve at bilstein Motorsport centers .
At least in europe they can , but better check over in USA ....

kreeshp · 02-04-2019, 08:17 PM

When I got my '90 964 C2, I upgraded from stock suspension to Bilstein HD and H&R 965 springs. This is one of the more common upgrades done.

Also have stock sway bars and Elephant Racing 'sport' hardness rubber bushings all around.

My car is 100% street driven and I have never driven any other 964's. I'm totally satisfied with how mine performs and the limiting factor to my car's performance is not my suspension setup but my driving skills. It performs more than well enough on the street.

ian c2 · 02-04-2019, 08:59 PM

Quote:

Originally Posted by kreeshp

the limiting factor to my car's performance is not my suspension setup but my drivingg skills. .

Let’s face , it no matter what you do to your car , no matter how much you spend , no matter how BIG you act on the Internet , how much you do at ax , at de, at club racing etc. , if Hamilton , Alonso , vettel etc. came out to play in a stock 911 you would be beaten ....

I own a couple of couple cars , and each one of them is a more accomplished car than I am an accomplished driver

Mike964_61 · Mike964_61's Garage

I have H&R coilcovers on my 90 c2, I love them. I take it on 5 hour road trips routinely within the state. Lots of different road conditions. I would say stiff suspension to one person may not be stiff to another. That one is tough to gage. I don't think mine is that stiff, but I also don't think GT3's are that stiff. If you are use to riding in a cush SUV then you are going to think anything is stiff. So it really depends on what you are use to.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by porsche gt3

Hi,

I am looking to upgrade the suspension on my 1990 964 C2. I will be driving the car mostly on the street with occasional track days. I am not looking for very stiff springs and want a ride similar to stock with enhanced handling.

I have been looking at the following:

Bilstein PSS10
Bilstein HD with H&R springs
KW v1
KW v3
H&R street performance coil over

strut tower bar (I have one)

urethane steering rack bushings

steering rack brace

993 GT2 inner tie rods

H&R adjustable sway bars

replace front control arm bushings with slightly stiffer rubber ones

leaving rear trailing arm bushings stock

replace spring plate bushings similar to stock only if bad

Please let me know your thoughts and experience with these components.

Thanks

David

One of the big factors in wrt the comfort and ultimate track performance is the shock valving
You want a digressive valve stack

PSS10 comes stock w/ a digressive stack matched to the car and for mostly street use might be the way to go. The nice thing here is that it'a complete engineered package, nothing extra to buy

The Bilstein hd and H&R(H&R is made by Bilstein) you would want to have a digressive revalve done and you ill need springs and perches which are usually sold separately

Don't know about the KWs

The rest looks good, Elephant or rennline sport rubber for the bushings is a great way to go.

dfhtrhjn · dfhtrhjn's Garage

I went with Bilstein hd + H&R lowering springs - the really common upgrade combo.
I also added the Elephant racing bump steer correcting tie rods - this makes a huge difference.

This was the stiffest I could go and still enjoy the coastal roads in Oregon. If it were my only 911 however, I would have definitely gone with Bilstein PSS10.

ISGASA · ISGASA's Garage

I have the Eibach Pro kit with Eibach adjustable sway bars and endlinks. Great ride, not too low or too stiff, but I am bias since I work there.

porsche gt3 · 02-05-2019, 05:51 PM

Thanks Guys. Lots of good information. My biggest decision is buying the shocks/struts. I really like the PSS10, but not sure if I want to spend that much money. Too bad a good used set isn't available for sale. Is there anything comparable to the PSS10 for less dollars?

ian c2 · 02-05-2019, 05:56 PM

Check the tops on the rear of your car .
They change the design during the 964 run .
There’s a work-around if needed.

dfhtrhjn · dfhtrhjn's Garage

I think the extra you pay for the PSS10 is negligible if you use it. Nothing is worse than buying shocks/springs (such as HD+HR springs) and realizing you should have spent a little more to get adjustability for track use.

You'll be really bummed if you go through the work of buying and installing something less expensive purely to save money and find out it doesn't perform the way you need it to.

porsche gt3 · 02-06-2019, 11:25 AM

Wow! Mr DFH.
That’s the best advice I heard. You are 100 % correct. This is what I would say, but dont always practice it.
PSS10’s it is

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by porsche gt3

Wow! Mr DFH.
That’s the best advice I heard. You are 100 % correct. This is what I would say, but dont always practice it.
PSS10’s it is

The more adjustable a shock is the more ways and higher likely hood that it will be adjusted wrong.

If you know what you are doing adjustability is great.

JMO but for most people having custom adjustable shocks built to your spec(chassis, springs, use) is the best way to go. Here you rely on the skill and knowledge of the shop or shock builder.

Elephant can provide this service for Bilstein, H&R and their line of Vonn shocks. The one constant is to use a digressive rather than linear stack.

MCS is probably the best w/ 964 price range from ~$2700 to ~$6000 a set + springs & perches

PSS10 are digressive stock and are a good value as you don't need to buy anything else, It can be instructive to DIY adjust them