I've poked around the forums and cut and pasted this listing of spring rates for JICs, PSS9, and GT3 coilovers.

JIC (linear)
soft - 7/10 (393/564)
med - 8/12 (450/674)

PSS9 (not sure if linear or progressive)
260/515

GT3
Front: 40 N/mm (228.44 lbs/in --> 225 lbs/in) linear
Rear: 95 N/mm (542.55 lbs/in --> 550 lbs/in) progressive

What are the stock spring rates for a mk1 996, mkII 996, row m030, x73, and x74?

 

Good thread..

 

Good luck with the X73/X74 rates...I asked around to several sources and could never get an answer.

I've got Stock / M030 and H&R spring rates somewhere in my desk...I'll try to dig them up for ya.

**EDIT** found them.

Stock rates (linear I believe) 146 F / 203 R
M030 rates (ROW AND US) 170 F / 260 R
H&R Springs (progressive) 170-210 F / 230-260 R

Andy

 

AudiOn19s - Yeah, I've looked around and couldn't find the x73/x74 spring rates. Thanks for posting the other spring rates.

 

FYI, I have decided to take my X-73 apart and analyize them completely when I get them. They have been ordered for just about a week now - stay tuned. IE: we are doing spring rates and a shock dyno. Will also advise if there is any alt setup for the shocks. eric

 

996 Standard and Sport
Suspensions Analyzed
Spring rate and shock dyno data comparing
different 996 C2 six-speed coupe factory
suspension configurations

By Russ Dickerson
Bob Gagnon
Mike Schatz

 

I have seen that chart but does not list X7X....
More later

 

I'm quite interested to see what you find with the X74 suspension. My gut tells me that the spring rates will be softer than say the PSS9 or GT3 but the damper curves will be pretty agressive.

Andy

 

Just browsing through some old posts of mine....Any update on the X73/X74 spring rates? Also, does anyone have the spring rates for the KW Variants, K-Sports, etc...

 

Here's a link to that article:

http://www.pca.org/panorama/sample_article_3.html

 

We found we could not dyno the front shock without making a jig so I just shined the whole exercise and bolted them on. eric

 

I wrote one of the guys who wrote this article and here's what he responded with.

*********************************************************
Unfortunately, Porsche does not publish their spring rates and we have not
done any testing, as we did for the article, for the X73/4 springs.
However, I can say that the spring ratios and shock valving will be very
similar to the Euro M030 with the exception that it will be a bit stiffer
owing to the lower ride height. The handling characteristics are very
similar the Euro M030 as it uses the same sway bars.
I hope this helps.

Regards,
Michael Schatz
Schatz Motorsport
P.O. Box 522
Camarillo, CA 93011-9990
USA
Phone: +1-805-482-7278
Fax: +1-805-482-3630
e-mail: sales@schatzmotorsport.com
www.schatzmotorsport.com

*********************************************************

 

OK, not the newest of threads, but the best on the subject. And there's a few interesting things in the colorful table above which no one commented on yet.

First, the standard and sport (M030) front springs differ in thickness from top to bottom, which very likely means they are progressive springs. (And certainly are if the diameter of the coil and the number of turns per inch/cm/meter, etc. of height are the same.)

There's only one stiffness measurement though. If the springs are progressive, then once they are compressed enough, the softer spring will be fully compressed and the stiffness will increase. And if there's only one measurement of the stiffness of a progressive spring, I'd guess it's the initial stiffness, before the softer part is fully compressed. If that's right, then the initial, softer spring rate will actually be stiffer than Bilstein PSS10 springs in their initial phase. (Apparently 93 and 113 lb/inch front and rear for 4wd cars - I haven't been able to find this for the 2wd cars).

Is this right - are the standard springs progressive? If so, don't suppose anyone knows how stiff the stock springs are at their stiffest?

Also interesting is that the same stiffness and same wire diameter is shown for both US and ROW M030 suspension. Based on my admittedly limited understanding of such things, if it's exactly the same spring except that one is shorter, the shorter one will be stiffer. (Suppose there are two identical springs except one is twice as long - the same amount of force will compress the longer one twice as much.)

The final interesting thing is that the same suspensions come in two versions: green and white; the green ones have 3mm shorter springs and make up for it with thicker compensator disks, whatever they are. Anyone have any idea what this is about???

Oh, and anyone know whether the whole table is for a 996.1, or a 996.2?

 

I realized that at their thickest, the standard front springs use thicker wire than even the rear sport (M030) springs, which have a stiffness of 260 lb/in, and as the stiff section of the fronts is probably shorter than the rear springs, they should actually be quite a bit stiffer. (Again, assuming there is no difference in spring shape/geometry.)

 

I don't think you are going to find too many people obsessing over springs and their composition. I think you maybe taking the same approach here like you did with the WAV vs FLAC analysis in your other thread. No offense.