Thanks for the feedback. Sorry but I won't need the 7 inch spring. If I go ahead it would also be 6 inch with helper, or 8 inch without helper, for the front.
1:1 ratio spring setup has been used by (good) tuners for track; there is a post/thread somewhere on rennlist track forum about this. In my car - setup by Lucent of Los Angeles, a seasoned pro and alignment "guru" - we match with GMG sway bars set to soft front stiff rear (to reduce understeer) and the result is fantastic. The problem is, it's an absolute beast in the twisties especially with R compound Pirelli Corsa, but on bad streets, it could be rough, and I am getting older LOL.

Actually come to think about it the main problem is me - can't leave well enough alone! I am just in the "thinking about it stage," handling will suffer if I go w/ softer spring so maybe I won't do anything. Thanks again and have fun with your car -- good to know someone else has also succeeded in finding the elusive replacement springs for Bilstein.

 

I wonder if you might actually just consider revalving the pss10's. If you look at this post: https://www.6speedonline.com/forums/...-bilstein.html it says the max spring rate for the stock PSS10's in front is 360lbs/in.

I'm thinking about a set of PSS10's right now and the fronts are at 260. That seems pretty soft. I daily drive this thing too, and may just go ahead and try the stock ones and see if i'd like it to be a little stiffer. Still thinking about it, though...

To be totally honest, though, with my loud (but not THAT loud) exhaust already, adding a stiff suspension may make it so nobody wants to ride with me in this thing. That's fine with me though..

 

I sent mine out to be revalved at Bilstein when switching the springs. You are correct - you need to do that.

My wife tells me that the ride is harsh, the exhaust is loud, and the GT3 seats press on her shoulders. I tell her that the car also sometimes has a high-pitched whine from the passenger seat, too.

Jon

 

+1. These jokes never get old.

 

That's not what my wife says...

 

Hi, I do not know data for 996 Turbo - mine is 997, and note the other difference is my set is actually not a PSS10, but a PSS10/Damptronic (Damptronic means the dampening is electronically controlled; there is no **** like the PSS9 or non-damptronic PSS10.). Anyway, regarding spring rate, at least for 997 Turbo, the Bilstein Damptronic front spring rate is 340 linear (helper spring 115, fully compressed at rest), therefore the max is unlikely to be 360. I posted some spring rates on page 168 LOL of this thread https://www.6speedonline.com/forums/...-turbo-12.html .

Regarding revalving, very tricky and it gets complicated (I was on phone with Bilstein numerous times and have read hundreds of posts on issues of coilovers, and still am not that sure :-).). I am an amateur so please take everything with a grain of salt, but here are the things I learned:
1. As spring gets stiffer, ideally what you want is to soften compression and stiffen rebound (If you think about it, the damper "sees" the stiffer spring rate only during rebound, and rebound dampening has to increase to control the stiffer spring "unwinding" with more force. OTOH compression damping actually might need to be decreased to ensure car doesn't become overly non-compliant and loses traction.). Because the PSS10 does not have independent bump/rebound - that's one of its weaknesses, and that's how KW Variant 3, higher level Bilstein, and Moton, etc., are different/better - I do not believe, at least for my PSS10 Damptronic, this could be done properly.
I posted shock dyno curve of dampening vs. speed (not the car's speed, the shaft/piston's speed) in the thread in my signature somewhere. In Bilstein PSS10/Damptronic, as mentioned the bump and rebound are paired, soft rebound paired with soft compression, hard rebound with hard compression. This is not necessarily ideal & hope I am making sense here.
2. The Bilstein *is* designed for different spring rates, so you could vary spring rate without having to re-valve. The tricky part is when to revalve, and here I don't get a consistent answer, but more or less, I think you are ok up to 100-150 increase, 150-200 you are taking a chance, and above 200 probably a good idea to re-valve. What you look for is sign of under-damped system ("porpoise" motion) and my car certainly has none whatsoever. Damper failure is another (obvious) sign.

At the time I changed my spring, I don't think Bilstein California has re-valved any Damptronic set yet, and I didn't want to be the guinea pig, especially with question about proper independent bump/rebound values unanswered. So we did (with Bilstein's reluctant blessing :-)) without revalving and the result has been nothing but fantastic. I made the mistake of driving a 2010 GT3 and would have sold my Turbo had it not for Bilstein and subsequent modification. Are you thinking about PSS10? Go for it! Both 996 and 997 Turbo are way too soft and the Bilstein will transform the car.

 

Here is the shock dyno for PSS10. AFAIK, the rebound and compression are *paired* in 10 levels - stiffest rebound paired with stiffest compression and so on down the line. This pairing - not independent of each other - is not necessarily ideal. Bilstein's more advanced coilover allows independent adjustment, and so do KW Variant 3 and Moton 3 way, etc.

That said, the bottom line is the result, and the result is fantastic. IMHO Bilstein is a God-send solution for a "mainly street, occasional track" purpose. That Bilstein also makes the OEM shock and uses Porsche chief test driver (Walter Rorhl) as consultant bring peace of mind.

 

cannga,
Thanks for all the info. I'm still deciding between PSS10's and KW V3's and am going back and forth. I started out looking at just installing in an x73 kit, but if I did that I'd be out of options. I suspect i wont race this thing much, though, so i may, once again, scale back my plans. We'll see. Thanks again!

 

You're welcome. No experience with KW V3 but I have heard only good things about it. You're not going to go wrong with either - Bilstein and KW would also be my top 2 choices, and you'll love the transformation. It becomes a different car, faster reflex, less body roll, less squating.

The final frontier is of course R compound tires, if you ever want to join the dark side. Stiff side wall, noisy, can't be used in the rain - but once you use it you may not go back.

Whatever you do, make sure only the best and most experienced tech touch your car's suspension. Good luck and have fun.