Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster Racing Forum

Post Reply
 
LinkBack Thread Tools Display Modes
Old 01-14-2020, 10:02 PM   #1
Registered User
 
Join Date: Aug 2019
Location: Essex
Posts: 42
Coil over spring rates

Hi. I’m trying to find someone that can give me some starting point on spring rates for a fast road 32s

Blue99 is offline   Reply With Quote
Old 01-15-2020, 08:14 AM   #2
Registered User
 
Join Date: Dec 2016
Location: Clifton, NJ
Posts: 1,135
450/500lbs is a good starting point. Its what spec boxsters use and frankly, with my feal coilovers, they are very comfy. As my car is almost purely a track car at this point, I'll likely upgrade to 600/650
Quadcammer is offline   Reply With Quote
Old 01-15-2020, 08:54 AM   #3
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Quote:
Originally Posted by Quadcammer View Post
450/500lbs is a good starting point. Its what spec boxsters use and frankly, with my feal coilovers, they are very comfy. As my car is almost purely a track car at this point, I'll likely upgrade to 600/650
What does it weigh?
Hasbro is offline   Reply With Quote
Old 01-15-2020, 12:48 PM   #4
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
This thread has a lot of discussion about various spring rates and their effect.
http://986forum.com/forums/performance-technical-chat/27222-m030-spring-rates.html

Different drivers like a different feel so there is no one perfect setup. BSR Spec race cars run 450/500 and a lot of guys like it but I don't want a car so tied down. Too much spring on a car without LSD results in wheel spin on corner exit. Wheel spin is slow.

On my 986 BSX dual purpose Time Trial car I went with 270F/370R and it was *just enough* spring to reduce roll and make quicker transitions while still having full grip on corner exit. That car was good for 5 TT Championships so it worked pretty well and was still reasonably comfy on the street. YMMV
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Old 01-15-2020, 02:27 PM   #5
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Quote:
Originally Posted by Topless View Post
This thread has a lot of discussion about various spring rates and their effect.
http://986forum.com/forums/performance-technical-chat/27222-m030-spring-rates.html

Different drivers like a different feel so there is no one perfect setup. BSR Spec race cars run 450/500 and a lot of guys like it but I don't want a car so tied down. Too much spring on a car without LSD results in wheel spin on corner exit. Wheel spin is slow.

On my 986 BSX dual purpose Time Trial car I went with 270F/370R and it was *just enough* spring to reduce roll and make quicker transitions while still having full grip on corner exit. That car was good for 5 TT Championships so it worked pretty well and was still reasonably comfy on the street. YMMV
Topless, I'm also curious about this topic. I learned to appreciate softer from a couple of Lotus'. What tires and bars did you use? Weight? Thanks.

Last edited by Hasbro; 01-15-2020 at 02:32 PM.
Hasbro is offline   Reply With Quote
Old 01-15-2020, 03:55 PM   #6
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
Quote:
Originally Posted by Hasbro View Post
Topless, I'm also curious about this topic. I learned to appreciate softer from a couple of Lotus'. What tires and bars did you use? Weight? Thanks.
The car was right at BSX class weight with no gas, 2950# w/driver

Tires: NT-01 225/255 (class tire)
GT3 Front sway, full soft
Tarret rear sway, full soft (disconnect for rain)

I sometimes ran 255 square on tight tracks or AX and would take a notch or 2 on the front sway to balance the car.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Old 01-16-2020, 05:52 AM   #7
Registered User
 
rastta's Avatar
 
Join Date: Feb 2014
Location: Cowtown CA
Posts: 369
It's also not just about spring rate. The type of shocks make a difference as well. I was very concerned with the spring rates on the Ohlins RT's (400lb front and 450 rear or something like that) I put in my Cayman as its my street car. Surprisingly enough, due to the valve design of the Ohlins - they were more compliant than the stock springs and shocks. My Boxster runs 700/800 as it's track only - and the Moton 2 ways were built for those rates.

Last edited by rastta; 01-16-2020 at 06:31 AM.
rastta is offline   Reply With Quote
Old 01-16-2020, 12:47 PM   #8
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
Quote:
Originally Posted by rastta View Post
It's also not just about spring rate. The type of shocks make a difference as well. I was very concerned with the spring rates on the Ohlins RT's (400lb front and 450 rear or something like that) I put in my Cayman as its my street car. Surprisingly enough, due to the valve design of the Ohlins - they were more compliant than the stock springs and shocks. My Boxster runs 700/800 as it's track only - and the Moton 2 ways were built for those rates.
Absolutely! Spring rate, dampening, ride height, tire choice, sways, all up weight, and setup are all important pieces of the equation that must be considered for best results. Changing one or two elements without considering the impact on other variables will sometimes make the suspension worse... much worse.

As instructors we spend a lot of time in other people's cars at the track. My impressions:
-Best by far: A well-tuned performance suspension with a pro setup.
-Next best: Bone stock with pro performance alignment.
-Often worse: DIY shade-tree suspension changes without an experienced pro connecting all of the dots.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Old 01-16-2020, 03:21 PM   #9
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
Quote:
Originally Posted by Topless View Post
... 270F/370R and it was *just enough* spring to reduce roll and make quicker transitions while still having full grip on corner exit.
I agree with Dave. ^^^ I also campaigned a BSX Boxster and posted 16 Time Trial wins and 2 track records.

I've driven Boxster's on the street and the race track with stock, 200, 270/370, 450/500, 650, and 800 spring rates. As others have said, there is no single perfect spring rate, because the springs have to match the rest of the components, setup, etc.

For any street/road going car, I would say that the BSX setup with 270/370 springs (the Bilstein PSS9 spring that comes with the shock) is a great trade off between stiffness and compliance.

I've driven thousands of street miles (and 100 races) on the 450/500 springs in my Spec Boxster and this setup is incredibly awesome when the roads are nice and smooth, but its generally too stiff for sporty street driving because the roads are often too rough resulting in a loss of traction, especially under hard braking and hard acceleration.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor

Last edited by thstone; 01-16-2020 at 03:30 PM.
thstone is offline   Reply With Quote
Old 01-16-2020, 04:47 PM   #10
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Good Stuff. Wish we had a like button. Topless, thstone, either of you run a square setup? Aren't the PSS9s going the way of the Dodo bird?
Hasbro is offline   Reply With Quote
Old 01-19-2020, 07:23 AM   #11
Registered User
 
Join Date: Aug 2019
Location: Essex
Posts: 42
Great discussion on this and some great answers. Thanks 👍
Blue99 is offline   Reply With Quote
Old 01-19-2020, 07:50 AM   #12
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
Quote:
Originally Posted by Hasbro View Post
Good Stuff. Wish we had a like button. Topless, thstone, either of you run a square setup? Aren't the PSS9s going the way of the Dodo bird?
Yes PSS9s are now being replaced by more advanced struts like JRZ, Moton, and others. A timely thread as my Cayman has 70k miles, of which maybe 20k on race tracks and the struts are pretty far gone. Having discussions now with my setup shop to determine the best dual-purpose struts and springs for my weekend joyride/track steed.

RE: Running square- I ran both ways and gathered a lot of comparison data. For tight tracks and AX I found 255/255 to be a bit quicker but longer tracks with higher speeds favored 225/255 for the fastest laps. They were very close but the trends were clear. In wheel to wheel racing there are advantages to having more grip in the front for quick moves and going deeper in the braking zones. I think most BSR drivers run 255/255 for this reason, as well as the ability to rotate all 4 corners for best tire management.

Others may have different experiences with tire choice but this is what I found over 10 years with my 986.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Old 01-20-2020, 08:17 PM   #13
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,669
Quote:
Originally Posted by Hasbro View Post
Topless, thstone, either of you run a square setup?
Yes, I ran both staggered and square. I held two track records running staggered. But once I went square, there was never any reason to go back. Braking and corner entry are hugely enhanced running square. I don't think that anyone runs staggered anymore in Spec Boxster.


Quote:
Originally Posted by Hasbro View Post
Aren't the PSS9s going the way of the Dodo bird?
Yep, the PSS9 is going obsolete. The new Spec Boxster shock is an MCS unit.

Read about it here: http://986forum.com/forums/boxster-racing-forum/74751-pca-announces-new-spec-boxster-shock-package.html
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
thstone is offline   Reply With Quote
Old 01-21-2020, 06:43 AM   #14
Registered User
 
rastta's Avatar
 
Join Date: Feb 2014
Location: Cowtown CA
Posts: 369
Quote:
Originally Posted by Topless View Post
Yes PSS9s are now being replaced by more advanced struts like JRZ, Moton, and others. A timely thread as my Cayman has 70k miles, of which maybe 20k on race tracks and the struts are pretty far gone. Having discussions now with my setup shop to determine the best dual-purpose struts and springs for my weekend joyride/track steed.

RE: Running square- I ran both ways and gathered a lot of comparison data. For tight tracks and AX I found 255/255 to be a bit quicker but longer tracks with higher speeds favored 225/255 for the fastest laps. They were very close but the trends were clear. In wheel to wheel racing there are advantages to having more grip in the front for quick moves and going deeper in the braking zones. I think most BSR drivers run 255/255 for this reason, as well as the ability to rotate all 4 corners for best tire management.

Others may have different experiences with tire choice but this is what I found over 10 years with my 986.
The Ohlins RT's I put on my Cayman are THE best street coilovers I've ever used. While not on my Cayman, I've owned KW V2's and V3's, Penske's, Bilsteins and others and the Ohlins are far superior on the street. I'll stick with my 2Way Motons on the track.
rastta is offline   Reply With Quote
Old 01-21-2020, 12:47 PM   #15
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Just had a very pleasant chat with the design engineer at Vorshlag (when I should be working). Wish I had recorded the very one sided informative discussion. I wanted to see what spring weights the Ohlins dampers can tolerate prior to damper modifications - Ohlins will only build 10n up or down, which would be about 330 lbs front/400 rear. We talked about my two different square tire selections, size, models, and car usage and he felt the springs would work very well. In a nutshell. no charge to change spring weights. I meant to ask him about a wider track and perhaps just staying with the 400/457 springs but that will be another discussion.

Last edited by Hasbro; 01-21-2020 at 12:57 PM.
Hasbro is offline   Reply With Quote
Old 01-21-2020, 05:29 PM   #16
Registered User
 
steved0x's Avatar
 
Join Date: Dec 2012
Location: FL
Posts: 4,143
Quote:
Originally Posted by rastta View Post
The Ohlins RT's I put on my Cayman are THE best street coilovers I've ever used. While not on my Cayman, I've owned KW V2's and V3's, Penske's, Bilsteins and others and the Ohlins are far superior on the street. I'll stick with my 2Way Motons on the track.
I've got the Ohlins on my Cayman and have about 10,000 miles on them and maybe 9 HPDE events, I love them and so has everyone that has ridden with me. I've never experienced any "higher spec track only" coilovers but for a dual.purpose hpde/weekend cruiser, I think they are great. When they wear out, and if I start trailering the car, I'll get them upgraded to a track only spec.
steved0x is offline   Reply With Quote
Old 01-22-2020, 09:17 AM   #17
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Thanks, looks like Ohlins is the way to go for me. I also spoke with Ohlins in North Carolina and they convinced me not to drop the spring rate and that I will be very happy with the 400/457 springs. Brian at Ohlins said to go as far as a 15 to 20 mm drop, possibly more but to be careful as there can be rear axle contact. That will be plenty and gives me maneuverability with my initial tires, which will also drop the chassis 1/2". I'm thinking initially to try a safe 100mm chassis to ground setting plus -13mm from the tires. About ready to start a build thread.
Hasbro is offline   Reply With Quote
Old 01-22-2020, 10:19 AM   #18
Who's askin'?
 
maytag's Avatar
 
Join Date: Mar 2018
Location: Utah
Posts: 2,446
I recently ordered the ohlins R&T "track package", which changes the valving to match my selected springs of 450/550.

If you haven't ordered yet, I highly recommend Josh at arcflash. If you need contact info, lemme know.

Sent from my SM-G970U using Tapatalk
maytag is offline   Reply With Quote
Old 01-22-2020, 11:03 AM   #19
Registered User
 
Join Date: Aug 2019
Location: Danielsville, Ga
Posts: 78
Quote:
Originally Posted by maytag View Post
I recently ordered the ohlins R&T "track package", which changes the valving to match my selected springs of 450/550.

If you haven't ordered yet, I highly recommend Josh at arcflash. If you need contact info, lemme know.

Sent from my SM-G970U using Tapatalk
I won't be ordering for quite a while but sure. Thanks, I'll give him a shout.
Hasbro is offline   Reply With Quote
Old 01-23-2020, 06:31 AM   #20
Registered User
 
rastta's Avatar
 
Join Date: Feb 2014
Location: Cowtown CA
Posts: 369
I went with the minimum drop - which on mine turned out to be 18mm. Another reason why I went with the Ohlins - and the fact that height and spring pre load are separate adjustments. The 400/457 are fine on the street.

rastta is offline   Reply With Quote
Post Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 11:26 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page