996 GT3 Suspension Improvements
10-24-2018, 10:27 PM
#16
Rennlist Member
10-24-2018, 10:35 PM
#18
Rennlist Member
Glen Yee Motorsports: spring dyno and shock dyno before and after.
http://www.glennyeemotorsports.com/
10-25-2018, 03:00 AM
#19
Advanced
Thread Starter
Matt Lane, here is Bilstein contact. I called them today. The guy on the phone (John I think) said they can do the re-valve job but they need the GT3 Bilstein struts part numbers to make sure they still have the parts. I asked him if they can re-valve the struts according to spring rate. He said no, they can increase/decrease the compression and damping by some given percentage. I asked him how do we determine the percentage. He did not give me any clear answer. It does not give me much confidence to send the struts to them.
Hours of Operation: Monday–Friday 7:30am – 4:30pm ,
PHONE
+1-800-537-1085
WEB
bilsteinus.com
THYSSENKRUPP BILSTEIN OF AMERICA
14102 Stowe Dr., Poway, CA 92064, USAHours of Operation: Monday–Friday 7:30am – 4:30pm ,
PHONE
+1-800-537-1085
WEB
bilsteinus.com
10-25-2018, 09:52 AM
#20
Rennlist Member
10-25-2018, 10:13 AM
#21
Worn LSD and rear twitchiness
.... I recently crashed it at Laguna Seca right after I had the PSS 9 rebuilt, corner balanced and re-aligned. The day that I crashed, my SPB felt extremely twitchy. I guess my previous setup was ok for worn shocks but with newly rebuilt shocks, the car felt totally different. ...
10-25-2018, 10:27 AM
#22
“Himself”, sounds like you and I have 2 things in common: 04 GT3 and SPB 
. Thanks for sharing your experience. I assume you had the bilstein struts re-valved to match the 700/900. With these spring rates, how does it feel for street driving? [It's pretty abrasive on the street. I only drive it once every month or two now. The roads in Houston are not smooth, so it can be a real challenge to enjoy it.] I still want mine to be streetable. Also, did you send the struts directly to Bilstein and where did you order your springs? [I originally got mine from Dan Jacobs as a set. Later, I had the rears rebuilt. They were sent directly to Bilstein. The shop handled the specs. H&R or Eibach? Diameters, length etc. these info will be helpful. Also, ride height? My ride heights have pretty much been the same for a almost a decade: ~115MM in the front; about 125MM in the back.
Speaking of trail braking, my daily driver BMW 228i M Sport trail brakes surprisingly nicer than the SPB. [LSD or the electronic equivalent makes a huge difference in trail braking. Open diff kinda sucks...] Much early to dial it in. As for the throttling with off/half/on switch mode driving coming out of a turn, I guess that’s generally our SPB driving style. I did the same with my old C2 with LSD. It works great. I had to tell my students to just stay on the gas even when you drop two wheels off the exit berm, especially if you have LSD. I can’t wait to test my GT3. I guess I’ll just soften up the rear sway first and see how it feels before spending money on it.
thanks for all the suggested comments!
. Thanks for sharing your experience. I assume you had the bilstein struts re-valved to match the 700/900. With these spring rates, how does it feel for street driving? [It's pretty abrasive on the street. I only drive it once every month or two now. The roads in Houston are not smooth, so it can be a real challenge to enjoy it.] I still want mine to be streetable. Also, did you send the struts directly to Bilstein and where did you order your springs? [I originally got mine from Dan Jacobs as a set. Later, I had the rears rebuilt. They were sent directly to Bilstein. The shop handled the specs. H&R or Eibach? Diameters, length etc. these info will be helpful. Also, ride height? My ride heights have pretty much been the same for a almost a decade: ~115MM in the front; about 125MM in the back.Speaking of trail braking, my daily driver BMW 228i M Sport trail brakes surprisingly nicer than the SPB. [LSD or the electronic equivalent makes a huge difference in trail braking. Open diff kinda sucks...] Much early to dial it in. As for the throttling with off/half/on switch mode driving coming out of a turn, I guess that’s generally our SPB driving style
. I did the same with my old C2 with LSD. It works great. I had to tell my students to just stay on the gas even when you drop two wheels off the exit berm, especially if you have LSD. I can’t wait to test my GT3. I guess I’ll just soften up the rear sway first and see how it feels before spending money on it.thanks for all the suggested comments!
Matt Lane, here is Bilstein contact. I called them today. The guy on the phone (John I think) said they can do the re-valve job but they need the GT3 Bilstein struts part numbers to make sure they still have the parts. I asked him if they can re-valve the struts according to spring rate. He said no, they can increase/decrease the compression and damping by some given percentage. I asked him how do we determine the percentage. He did not give me any clear answer. It does not give me much confidence to send the struts to them.
For $100 bucks a corner for the revalve (mine was $65 + $35 overnight shipping!), I might even roll the dice and pick a percentage based on a little common sense and investigation. I bet a few calls would get you to a very close answer.
EDIT - Here's a link from 2011 about the suspension change and first impressions.
EDIT2 - Here's another helpful link with spring lengths and related info.
-td
Last edited by himself; 10-25-2018 at 10:51 AM.
10-25-2018, 02:47 PM
#23
Rennlist Member
I really don't drive it on the street hardly at all. Trailer to/from the track. I may be a little above the cup height in the front...at cup height the bottom of the front stock coilovers hits the top of the ball joint bolt.
I've been talking to Chris Cervelli about setting up the car this winter. He's recommending JRZ triples and various 997 RSR arms on the rear, plus a touch of his wizardry.
I've been talking to Chris Cervelli about setting up the car this winter. He's recommending JRZ triples and various 997 RSR arms on the rear, plus a touch of his wizardry.
11-02-2018, 07:38 PM
#26
Advanced
Thread Starter
Here is my update. I spoke with Dan Jacobs (super nice guy). He said the people at Bilstein doing the re-valving job are no longer there. But Dan looked up the valve settings for matching the 500 lbs/ 700 lbs spring rates. I called Performance Shock Inc (PSI) in Sonoma (they rebuilt the PSS9 on my SPB https://performanceshock.com/). I gave Tom from PSI the settings. He got it right away. He said he can take care of it including installing the springs if I send them the entire units. The whole thing including replacing bottom bushings for ~$1500. It will take 2-4 wks turn around time. I hope this helps. By the way, PSI also sells Ohlins R&T coilovers for $2925. You can specify the spring rates as long as they are within the range of the valving. The re-valving w/ 500/700 lb springs costs about half of a set of Ohlins R&T. I think I will go with the re-valving route.