MassGuy

I am thinking about working on the suspension on my 1991 C4. I would like to lower the car as well as upgrade the suspension so I can experience a tight street car with track qualities....

I am interested in suggestions and some guidence because I have never dealt with suspensions. I am thinking I will want to do the install myself. I have limited mechanical skills but I feel I am capable if I take my time.

Where should I go to buy my parts?

What are my choices?

Got pictures?

Thank you!

91carrera4

Looking for the same info. Thinking about bilstein HD and H&R greens, any thoughts? Also how harsh are the sports vs the HD?

ilko

I just purchased a set of Koni adjustable shocks and Eibach springs. I've had Konis on my other cars and like the adjustability. I also like the fact that the Eibach springs don't drop the car as low as H&R.

And of course, after reading the 964 C4 suspension article in Excellence I was sold

Excellence article in question

Red rooster

Maybe the first thing to do is consider what kind of use the car is mainly for.
If it is street , then what is the road surface quality like ?
A super low 964 running hard springs is a nightmare on poor roads and will destroy driving pleasure !
Good dampers are a must. I run Koni top adjusts all round with C2 front springs . The set up is still fairly hard but I get away with it here where the roads are not the best !!

A really good 4 wheel alignment by someone with lots of 911 experience is vital.

Good luck with whatever you decide .

Geoff

MassGuy

Geoff?

What does your car height look like?

Any pictures?

Ilko?

DO you plan on installing them yoursel?


Thanks guys....

ilko

Yep, I'm doing it on my own.

Steven C.

I agree with Geof. I have Bilsteins HD with Eibach and the car is fairly low. Pretty rough on good roads but would not do it if I drove on rough roads all the time.

flat_six

Last summer I installed Bilstein HD dampers and H&R green springs on my USDM 1991 C2. The car was built in Sept 1990. Porsche revised the rear suspension in Oct 1990. The changes included the rear shock mounts and dampers (shorter). I'm not sure that this applies to the C4.

The damper options are limited for this early suspension design. The Bilstein HDs for pre-91 cars are still produced. There is no Sport damper available. Sadly, the Koni adjustable dampers are no longer produced for these cars. There are other damper options, such as euro M030 or H&R coilovers. They cost significantly more, but you get what you pays for. The Bilstein HD and H&R Greens together cost about US$1000. The Bilsteins allow for a small spring perch adjustment for rudimentary corner-balance, but no pre-load adjustment.

The typical ride height with the H&R greens is 25.5" to the fender. A bit more than 1" drop. Watch out for parking blocks, speed bumps, etc! I feel that the Greens are not harsh at all, and are a reasonable compromise for the street. Some use the Reds (H&R Turbo) with the HDs. I wonder about how the car would ride with the damping rates of the HD's and the stiffer Reds.

Danz C4

I have had the Bilstein HD and H&R Greens for about 4 months now. 1990 C4 Cabriolet. I also bought new tires at the same time. Michelin Pilot A/S 16" 225/55 front, 245/50 rear. 1/4" spacers on the front. Installed a strut brace. Some minor rubbing at extreme L/R. I have the steering stops, I'll install eventually. That looks like a lot of work. Suspension aligned to RS specs. Not corner balanced yet. I'm trying to figure a way to do this myself without buying the scales. Anyone want to go in on a set and FedEx them around?

This car is a driver and encounters a mix of city and freeways. I agree with flat_six, the ride is not what I would call harsh. It is firm and simply feels right. "... a tight street car with track qualities..." sounds good to me. Remember that the H&Rs are progressive, so 'normal' driving will not encounter the harshest reaction in these springs.

The ride height is very low for a street car. With my son and 11 year old grandson in the car with me, it will rub at speed a couple of times on the drive between Portland and Seattle. This happens when I cross a joint in the road that is an obvious bump. I haven't figured out if it's front or rear.

The installation is not difficult. Get Adrian's book, and order the nuts and bolts from Sunset Porsche. Figure an all day job with a helper, for all the work. Ordinary shop tools, including a torque wrench. You will have to un-do the front brake lines so be prepared for that. Then, you will need an alignment, and corner balance.

I have pictures but there are lots of links out there already. http://www.porsche964.co.uk/

Danz C4

Red rooster

Massguy,

Sorry but I have no pictures that will show what you want ! Its so long ago that I have forgotten the detail but some of the C2 front springs run the ride height about 10mm lower than regular C4 springs. It was a token attempt to lessen the SUV look !

The 90/91 rear change was dropping the rear tower top by 20mm to accomodate the Cabriolet needs. The later rear mounts have a different stud pitch as a result. For other reasons I had a pair of 20mm aluminium spacers made to convert from one pitch to the other when I used late top mounts on an 89 C4 .Doing that meant I could use late or early rear Koni dampers.
Front Koni are the same for all 964s.

The other element in ride comfort is whether you have 16 or 17 inch rims .
16s are much more forgiving with their taller side walls.

All the best

Geoff

hawk911

I did HR Turbo springs (reds) and Bilstein HD shocks. Love the height and the ride. I did the RS alignment specs. Do a search as this may be the top discussion on the board.

MassGuy

I am doing a bunch of research both on here and pelican. So much good information to digest. I love these boards....

Anyway this is what I am looking at and I think I am going to buy them....

Navigate: StoreFront / Porsche / 964 / Porsche 964 H&R Coilover Kits / Porsche 964 C2, C4 H&R Street Coilover 1991-94

Product Type SKU Description Price
Porsche 964 C2, C4 H&R Street Coilover 1991-94

29580-2 Porsche 964 C2 & C4 H&R Street Coilover Setup F1.0-1.7 R1.0-1.7 91-94 $2,250.00
$1,755.00








View Enlarged Image
Engineered for street and occasional track use, H&R Coil-Overs feature a fully-threaded shock body (not an imitation sleeve-over) that allows you to precisely dial in height adjustment to achieve optimum weight transfer, or simply get the aggressive look you've been looking for. Featuring H&R's exclusive dynamic damper technology, each shock is engineered to work in harmony with a progressive-rate spring, together creating a finely-tuned suspension system.



Please tell me what I should expect!

ilko

The link doesn't work. Are you buying just springs? I would change the shocks as well, since the stock ones are not made to handle the extra pressure from the lowering springs and will wear out faster. Your comfort will also suffer.

ducnine

Hey guys,

Am I missing something here?

Where do you all find the H&R Greens and Reds that fit the 964? All I can find are Black ones on all the websites I have searched.

I even looked on the H&R Website and they show the only fitment as sport springs?

hawk911

The RED are for Turbo cars, but fit the NA cars also. I got mine from a Rennlister, so I can't help you with a new sourcer.