best 964 suspension?

[wastintime]

Hey everyone,
My '93 RSA is going to the track next weekend, and when I get back we're planning on redoing the coilovers. Right now it has the stock RSA springs and struts. I wanted to get some of your opinions on what are the current best setups available for 964s, since we haven't done a lot of track suspension work on any except for my old C2 at our shop.

I'm actually trying to stay away from too much adjustability. It's nice to have adjustable shocks when you want to have different street and track settings, but sometimes it's nice to have a set of shocks that just work and you don't have to screw around with.

I'm mainly looking at the H&R coil over kit for the RSA and C2 turbos. The spring rates seem fairly comparable to the euro RS, and the shocks are valved for those rates. Granted H&R isn't as well known for shocks as some other companies. It is fairly inexpensive though.

Bilstein is a company I'd really like to try. Unfortunately the PSS-9 is not available for 964s. Still, some nice shocks i could have valved for the springs i want to run would be great, especially with fully threaded bodies.

I know Koni used to make a really nice doubly externally adjustable suspension package for 964s, but i haven't seen any for sale recently.

Anyway, if anyone has upgraded the suspension on their 964 I'd really love to hear what was done and what your impressions are. I'd really love to get some opinions on the different coil over kits and how they drive on the track mainly, and also on the street. Thanks in advance guys.

Andrew

[RonnieM]

have you tried doing a search on rennlist.com in the 964 forumn? there is a bunch of guys with the bilsteins and h&r turbo springs there.

[wastintime]

lol, the rennlist search is a nightmare... at least some names i've been looking at keep pooping up which is nice, and they ive a few good distributors of 964 suspension packages. Apparently there is a pss-9 setup available for 964s from FVD, but it's about $1k too expensive. some of those guys are nuts too. I think what may help me decide is that most people that are big proponents of the bilstein pss-9s must have very different driving styles than I do. I'd never even consider for a second making the rear of a 964 as stiff as they say they've made theirs.

Like I said it's nice to hear that H&R keeps popping up with a lot of good reviews because their coil over kit seems to be the most cost effective way to go. I don't really want to do the supercup kit because it's way to expensive and way too stiff IMHO.

[Jack Olsen]

I'm curious. What are the stock spring rates on a 964, and what is the typical track-duty size?

[Carrera3.5L]

Just so you know, H&R buys their shock housings from Bilstein, and than valves them and finish manufactures them to their own specs.

Not a rep for H&R, but maybe it will help with your decision.

Ralph

P.S.- I have a whole slew of part numbers and info from the stillborn Carrera Cup series in the early 90's, PM me if you want suspension parts part number info. Don't know if these parts are the "hot" set-up or obsolete. Also don't know the current prices now (have old DM prices), you would have to call Porsche Motorsport.

[Carrera3.5L]

Originally posted by JackOlsen
I'm curious. What are the stock spring rates on a 964, and what is the typical track-duty size?

Jack, which spring would you like info on? Depending on the color code on the spring, progressive/linear and application will determine the spring rate. I have 8 different front spring and 7 different rear spring rate, part number and application. Anywhere from stock C2 to Carrera Cup.

Checked these all on Eibach's spring tester when I was at Andial in the early 90's.

Ralph

[wastintime]

Jack, the info I've got on stock spring rates for 964s is as follows:

89-91 C2/C4 Front: 158 Rear: 189

92-94 C2/C4 Front: 169 Rear: 189

91-94 M030 option/RSA/3.3 Turbo Front: 169 Rear: 263 (progressive)

92 RS and Cup Front: 247 (prog.) Rear: 440 (prog.)

Carrera Cup Car Front: 200-600 Rear: 240-800

[wastintime]

Ralph, thanks for the info on the H&R Shocks... that does make a big difference to know about H&R buying bilsteins and revalving them. The only thing that turns me off the the H&R kit is that it uses progressive rate springs which I'm not crazy about. Right now I'm waiting to hear back from Smart Racing how much a set of Bilsteins with (and valved for) linear springs (Front: 285 Rear: 450) would cost.

[Carrera3.5L]

Originally posted by wastintime
Ralph, thanks for the info on the H&R Shocks... that does make a big difference to know about H&R buying bilsteins and revalving them. The only thing that turns me off the the H&R kit is that it uses progressive rate springs which I'm not crazy about. Right now I'm waiting to hear back from Smart Racing how much a set of Bilsteins with (and valved for) linear springs (Front: 285 Rear: 450) would cost.

No problem, although I have seen Sachs Race Engineering housings being used as well (in VW applications). I think if one manufacturer is out they substitute for the other. Can't go wrong with either one.

BTW, your spring rate numbers are different than mine. I don't know how yours were measured, but mine are measured at 1" from rest and again 1" before coil bind on the progressive applications. Perhaps that is where the difference lies, the numbers you have were taken at a different referece point.

Anyway, too lazy to type out a slew of part numbers, but here is what I have otherwise:

Front

Color Code Type Spring Rate(lbs/in) Application

"Blue" linear ??? C2/Turbo >91
"Orange" linear 163 C4 >91
"Green/Yellow" progressive 85-179 C4 Sport
"Green" linear 146 C2/Turbo 92>
??? linear ??? C4 92>
"Yellow" progressive 65-280 Carrera RS
??? progressive 150-550 Carrera Cup
ANDIAL Spring progressive 81-293


Rear

"Blue" progressive 166-176 C2 manual trans
"Green" progressive 220-278 C2/C4/Turbo/M030
"Orange" progressive 178-185 C2/C4 Tiptronic
"Green/Yellow" progressive 153-286 C4 Sport
"Yellow" progressive 146-550 Carrera RS
progressive 252-686 Carrera Cup
ANDIAL Spring progressive 156-210

I've got a couple gaps, didn't have EVERY spring to test, but there should be enough info here for you to make a more informed decision.

Kind Regards,

Ralph

P.S. - If you would like a Porsche part number for a particular spring, PM me.

Sorry this reads like crap, can't figure out how to space everything. Space bar and tab don't seem to work very well. If someone can clue me in on how to spread it into columns, I will be glad to try and edit it to be more readable.

[wastintime]

I have no idea how the rates were measured, they are supposed to be the factory rates in lbs/inch. It's in the march issue of Panorama.

[Jack Olsen]

Thanks! I have coil-overs on my car, but there's not a lot of information I've seen on spring rates for early cars, beyond the ususal torsion bar suspects.

Andrew, is this for a dedicated track car? My spring rates are higher than you're talking about, and my car is still an (almost) daily driver. (For shocks, I've got custom-valved Bilsteins in back and single-adjustable JRZ's in front. )

[wastintime]

Jack,
Yes and no, it's getting to be more of a track car, but it will still get driven on the street an awful lot. as light as your car should be compared to mine, I'm a little surprised to hear you run much higher spring rates, but at the same time, I don't know how well you can really compare spring rates on our cars, btw, are yours progressive or linear? For some reason I have seen people, more so on 964s than any other car, just make the spring rates insanely high IMO.

[Jack Olsen]

I run essentially 400#/600# springs, F/R. I say 'essentially' because the rears are linear 600# springs, but the fronts are a combination of two springs -- a 400# and then something like a 95# short spring that is an "active tender" spring, only functioning when the suspension is not being compressed very much at all.