Anyone here run Bilstein PSS9's?
03-17-2008, 10:24 AM
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Anyone here run Bilstein PSS9's?
I've searched and searched but can't seem to find anyone running PSS9's on their RX-8. My roommate had them on his S2000 and I thought they were amazing, better than stock ride and much better handling. I was kinda wondering if people had tried them on the RX-8 and didn't like them for some reason. I noticed that the RX-8 has the cheapest price of any application I've seen. I've really been put off from doing struts/springs because of the weak sauce spring rates all of them have. Anyone have any details on the bilsteins used in the 40th anniversary? Are they just Bilstein HD's with stock springs? Any answers or input would be appreciated.
03-17-2008, 03:17 PM
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Nobody has PSS9s as everyone is kind of scared of the quoted spring rates that Bilstein is supposedly using and think it's going to really screw up the handling balance. However, if you're curious you can try it out. I'm not sure that Bilstein would make a product that has an end result as bad as some of the people are afraid of. I'm curious about the Bilsteins, but I don't currently have enough money built up in my car fund to purchase coilovers.
03-17-2008, 04:19 PM
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I was the one that quoted their rates a while back when I looked into them. The springs were biased to the rear being stiffer than the front. At the time, I openly questioned the logic here regarding their specs. They may in fact work very well, but I ultimately decided against them. Not to over simplify, but maybe if you were running a staggered setup these could go quite nicely - kind of like the S2K which in many years was biased with stiffer rates in the rear...
03-17-2008, 04:53 PM
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Thanks for the info guys. I may try them out if I can't find anything else that fits my requirements. I'm really not a fan of KW coilovers and I thought I read that they make the Mazdaspeed ones. I suppose if I find I don't like the PSS9's I can just get some softer springs for the rear and have the dampers revalved.
03-17-2008, 06:38 PM
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Actually Eibach makes the Mazdaspeed Coilovers.
https://www.rx8club.com/rx-8-racing-25/new-suspension-kit-119640/
https://www.rx8club.com/rx-8-racing-25/new-suspension-kit-119640/
04-05-2008, 09:44 PM
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So I've been thinking about the PSS9s; if the springrate really is what it is, perhaps the balance can be tweaked by running a stiffer front bar with a OE rear bar or by removing the rear bar altogether. Peppy, did you get the PSS9s or not?
04-06-2008, 09:52 AM
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Lionzoo - I haven't gotten the PSS9's yet because at this time Bilstein is reengineering their coilovers with new rates that are more in line with the stock suspension and other brands of coilovers. My dealer is getting an email once they are ready. If it takes too long for this to happen I may go with the Eibachs as I really hate KW V3's and think they are junk. I've driven an Evo, STI and S2000 with them and was completely unimpressed with the quality and performance. I had AST's on my WRX which I loved, but I'm trying to keep costs down and do very few mods to the RX-8. Basically I'm only doing wheels/suspension.
04-06-2008, 01:13 PM
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Lionzoo - I haven't gotten the PSS9's yet because at this time Bilstein is reengineering their coilovers with new rates that are more in line with the stock suspension and other brands of coilovers. My dealer is getting an email once they are ready. If it takes too long for this to happen I may go with the Eibachs as I really hate KW V3's and think they are junk. I've driven an Evo, STI and S2000 with them and was completely unimpressed with the quality and performance. I had AST's on my WRX which I loved, but I'm trying to keep costs down and do very few mods to the RX-8. Basically I'm only doing wheels/suspension.
04-08-2008, 11:17 AM
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So I called up Bilstien today and got the answers I was looking for. When Red Devil got the Spring rates previously he missed a very important detail. He was correct that the rates were 370lb/in for the front and 375-445lb/in progressive for the rear. But the part he missed was the helper spring in the front also has a rate of 145lb/in, which helps in making the front stiffer than the rear. I had a feeling Bilstein wouldn't mess up like that. I'm going to pick up a set in the next couple weeks I'll let you guys know how they are.
In short PSS9 rates are 370+145lb/in helper spring front and 375-445lb/in progressive rear. The newest part number is GM5-B029-H0
In short PSS9 rates are 370+145lb/in helper spring front and 375-445lb/in progressive rear. The newest part number is GM5-B029-H0
04-08-2008, 11:24 AM
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So I called up Bilstien today and got the answers I was looking for. When Red Devil got the Spring rates previously he missed a very important detail. He was correct that the rates were 370lb/in for the front and 375-445lb/in progressive for the rear. But the part he missed was the helper spring in the front also has a rate of 145lb/in, which helps in making the front stiffer than the rear. I had a feeling Bilstein wouldn't mess up like that. I'm going to pick up a set in the next couple weeks I'll let you guys know how they are.
In short PSS9 rates are 370+145lb/in helper spring front and 375-445lb/in progressive rear. The newest part number is GM5-B029-H0
In short PSS9 rates are 370+145lb/in helper spring front and 375-445lb/in progressive rear. The newest part number is GM5-B029-H0
Either way, would be great if you posted pics and let us know how it goes.
04-08-2008, 11:45 AM
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It could be a recent change because i asked her if it was a newer part number and she said it had changed. Maybe the revision I had heard about was the addition of the helper spring. Shox.com has the new part number listed and the price is $100 more than the set they were blowing out a month ago. If I recall it had a different part number.
04-08-2008, 01:21 PM
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I'm guessing the spokesperson just neglected to mention the tender springs. A 370 rate without tender springs would mean a very small amount of droop, though I'm kind of worried about rear droop now as it looks like the rears don't have tenders. Anyway, I'm glad you're going to try out a set, tell us how it goes!
Also, technically the springrate of springs in series is calculated with the formula 1/Keff = 1/K1+1/K2. Of course, that formula is useless for calculating coilover rates as the tender spring is designed to compress before the main spring.
Also, technically the springrate of springs in series is calculated with the formula 1/Keff = 1/K1+1/K2. Of course, that formula is useless for calculating coilover rates as the tender spring is designed to compress before the main spring.
Last edited by LionZoo; 04-08-2008 at 01:50 PM.
04-08-2008, 07:40 PM
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This is how according to Eibach the Calculation goes for for Tender / Main springs combinations.
Btw I have an e-mail that Bilstein sent me with the exact specs of the springs in this kit , but the e-mail is at work I'll post it tomorrow.
To help you determine the best combination of MAIN and TENDER
spring for your situation, Eibach has developed a computer program
called the ERS Wizard. Every chassis / suspension / driver is
unique therefore we suggest that you utilize the ERS Wizard to fully
understand the dynamics of the double spring combination before you
go testing.
The ERS Wizard is available from Eibach on CD-ROM. Below we have
listed the formulas for determining the initial and final rate as well as
the transition point between the two. These are the basic formulas
behind the ERS Wizard.
The following formula is used to determine the initial spring rate:
Ci =(CM x CT)/(CM + CT)
Ci Initial Spring Rate
CM Spring Rate of Main
CT Spring Rate of Tender Spring
The final spring rate (effective after the tender spring is closed)
is simply the rate of the active Main spring.
The following formula is used to determine the transition point
between the initial rate and the final rate:
TP =(Fc) t/(Ci)
TP Translation Point
Ci Initial Rate of Main/
Tender Spring Combination
(Fc)t Block Load of Tender Spring -
see Application List
Please note: the main/progressive tender spring combination has various
rates and transition points and as a result the respective formulas
required to determine the rates and transition points are more complex.
Please refer to the ERS Wizard for these calculations.
spring for your situation, Eibach has developed a computer program
called the ERS Wizard. Every chassis / suspension / driver is
unique therefore we suggest that you utilize the ERS Wizard to fully
understand the dynamics of the double spring combination before you
go testing.
The ERS Wizard is available from Eibach on CD-ROM. Below we have
listed the formulas for determining the initial and final rate as well as
the transition point between the two. These are the basic formulas
behind the ERS Wizard.
The following formula is used to determine the initial spring rate:
Ci =(CM x CT)/(CM + CT)
Ci Initial Spring Rate
CM Spring Rate of Main
CT Spring Rate of Tender Spring
The final spring rate (effective after the tender spring is closed)
is simply the rate of the active Main spring.
The following formula is used to determine the transition point
between the initial rate and the final rate:
TP =(Fc) t/(Ci)
TP Translation Point
Ci Initial Rate of Main/
Tender Spring Combination
(Fc)t Block Load of Tender Spring -
see Application List
Please note: the main/progressive tender spring combination has various
rates and transition points and as a result the respective formulas
required to determine the rates and transition points are more complex.
Please refer to the ERS Wizard for these calculations.
04-09-2008, 08:11 AM
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As promised
Then I asked This
And she was so kind and responded with this
So there you have it, now try and make some sense out of it and if you do please let me know.
Good morning! The PSS9 kit for the Mazda RX8 is GM5-B029-H0. The Front spring rate is: 370 lbs/in (main), 145 lbs/in (tender). The Rear spring rate is: Pregressive. Working range: 375-445 lbs/in. Please let me know if you have any further questions.
Thank you,
Rebecca Kellerman
BILSTEIN Shock Absorbers
Thank you,
Rebecca Kellerman
BILSTEIN Shock Absorbers
Hi Rebecca,
Thanks for the prompt response. It is greatly appreciated. I have a couple of more questions.
1.The stock spring rates on the RX8 are 150 lbs/in front and 113 lbs/in rear. Why is the ratio between the pss9 fronts and rears so different from stock?
2.What is the free lengths of the springs and the inside diameter of the springs?
3.Would it be possible to use a system such as ERS Eibach Springs or something similar that will enable the end user greater flexibility in suspension set-up?
4.If so what is the range of spring rates that the PSS9 struts effectively control without having to be revalved?
I realize you may not be able to answer all the questions, but this would really help to make my purchase decision.
Thanks again for your time.
Thanks for the prompt response. It is greatly appreciated. I have a couple of more questions.
1.The stock spring rates on the RX8 are 150 lbs/in front and 113 lbs/in rear. Why is the ratio between the pss9 fronts and rears so different from stock?
2.What is the free lengths of the springs and the inside diameter of the springs?
3.Would it be possible to use a system such as ERS Eibach Springs or something similar that will enable the end user greater flexibility in suspension set-up?
4.If so what is the range of spring rates that the PSS9 struts effectively control without having to be revalved?
I realize you may not be able to answer all the questions, but this would really help to make my purchase decision.
Thanks again for your time.
Hope this helps:
1) The motion ratios have been altered and resultant springs rates changed to optimize vehicular handling and balance.
2) Front: Main= 70mm i.d., 200mm free length, tender= 70mm i.d, 60mm free length
Rear: 97.5mm upper(o.e) i.d. & 60mm lower, 252mm free length.
3) Eibach ERS springs can be used for the front application.
4) Front: ~340-400lbs, Rear: ~350-500lbs.
Thank you,
Rebecca Kellerman
BILSTEIN Shock Absorbers
1) The motion ratios have been altered and resultant springs rates changed to optimize vehicular handling and balance.
2) Front: Main= 70mm i.d., 200mm free length, tender= 70mm i.d, 60mm free length
Rear: 97.5mm upper(o.e) i.d. & 60mm lower, 252mm free length.
3) Eibach ERS springs can be used for the front application.
4) Front: ~340-400lbs, Rear: ~350-500lbs.
Thank you,
Rebecca Kellerman
BILSTEIN Shock Absorbers
Last edited by ThecdnRX8; 04-09-2008 at 10:11 AM.
04-09-2008, 03:41 PM
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Motion ratio as in lever arm ratio for the A-arms or as in front and rear frequency ratio? How would you even change the lever arm ratio with just a coilover set?
04-09-2008, 06:10 PM
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Tell you guys what. I'll take pics of my entire install and the coilovers. Then I'll post my impressions, which you can take with a grain of salt. Worst case for me I can try swapping out the front springs with 400lb Eibachs and throw a big ol front sway bar on the front. I'm a big believer in Bilstein and I'm sure they put some R&D into this setup. I'll prolly have them installed by the end of the month, gotta have em on before I put my wheels on.
04-09-2008, 06:23 PM
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Tell you guys what. I'll take pics of my entire install and the coilovers. Then I'll post my impressions, which you can take with a grain of salt. Worst case for me I can try swapping out the front springs with 400lb Eibachs and throw a big ol front sway bar on the front. I'm a big believer in Bilstein and I'm sure they put some R&D into this setup. I'll prolly have them installed by the end of the month, gotta have em on before I put my wheels on.
Last edited by LionZoo; 04-09-2008 at 08:24 PM.
04-09-2008, 07:44 PM
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I'm sure the product won't be a disappointment. Blistien is a very good company. And the fact that they are providing this detailed information is a sign of that. I have contacted sereval companies and not all of them were that forth coming .
Just because I or anyone else on this board does not understand what they are doing doesn't mean much. So I am waiting for you driving impressions.
Btw do you plan on tracking your 8.
Just because I or anyone else on this board does not understand what they are doing doesn't mean much. So I am waiting for you driving impressions.
Btw do you plan on tracking your 8.
04-09-2008, 09:30 PM
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Ya, I've got a few track days planned for this summer. My is is my daily driver for now so I'm not looking for all out race coilovers and feel Bilstein makes a good compromise between handling and ride comfort. I never got to track my WRX except for the drag strip(had twice the whp as the 8), and I bought the RX-8 for it's handling and for some light track and auto-x use.
04-16-2008, 08:50 AM
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Just to keep you guys updated. I ordered the PSS9's and they will be here next Tuesday. I'll take pics of them. Hopefully I'll have time to install them that weekend.
