Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical Chat

Post Reply
 
LinkBack Thread Tools Display Modes
Old 08-14-2012, 03:02 PM   #1
Registered User
 
LAP1DOUG's Avatar
 
Join Date: Aug 2011
Location: USA
Posts: 414
It sounds like you have made up your mind what you want, so I will not try to dissuade. I do not have this set up, but can offer the following info:

1- Sway bar stiffness is a function of the 4th power of the bar OD, so the OD is all important, and a solid bar will not be much stiffer than a hollow bar. Purchase Fred Puhn's excellent book, and you can calculate it yourself.

2- According to my set-up notes, my 986S had originally a 24 mm front bar, and 19 mm rear bar, so I don't see this set up being much stiffer than my original stock set-up, but yours may be different. According to my calculations, my original stock bar had a stiffness of about 330 lb/in. For reference, the GT3 front bar at position 1 of 5 (softest setting) is about 430 lb/in. You can get the dimensions and calculate the H&R bar for comparison.

3- The way I see it the real advantage of a front bar on these cars is camber control needed due to the poor camber curves in roll with a McStrut suspension. Adding stiffness in the front should reduce understeer up to the point where you have the best camber control you can get, then after that weight transfer effects take over, and it will start to increase understeer. Trial and error is needed to find this sweet spot.

4- I don't really see what changing the rear bar is all about.

Good luck
__________________
Kippis

986S
991S
Van Diemen RF97
LAP1DOUG is offline   Reply With Quote
Old 08-14-2012, 06:37 PM   #2
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
I've never used them. Reports from those who have: "Eibachs are stiff as hell!" Caveat: This is hearsay only and not personal experience. YMMV
Try a base M030 bar on the rear and leave the front alone. Guys in the know say this is the trick setup. Much improved rotation but not so stiff you give up traction on corner exit. My brother runs this setup to good effect. Try it, you might like it.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.

Last edited by Topless; 08-14-2012 at 06:42 PM.
Topless is offline   Reply With Quote
Old 08-15-2012, 08:04 AM   #3
Registered User
 
Join Date: Jun 2012
Location: Where there is no road course
Posts: 91
Garage
Quote:
Originally Posted by Topless View Post
I've never used them. Reports from those who have: "Eibachs are stiff as hell!" Caveat: This is hearsay only and not personal experience. YMMV
Try a base M030 bar on the rear and leave the front alone. Guys in the know say this is the trick setup. Much improved rotation but not so stiff you give up traction on corner exit. My brother runs this setup to good effect. Try it, you might like it.

Does this advice still apply now that you know my experience level

Did the rear bar alone help with the body roll of the car?
Boxster586 is offline   Reply With Quote
Old 08-15-2012, 08:45 AM   #4
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
Quote:
Originally Posted by Boxster586 View Post
Does this advice still apply now that you know my experience level

Did the rear bar alone help with the body roll of the car?
I suggest leaving the sways alone for now. After a year of performance driving you will totally "get" the rear sway bar change. Body roll is best managed with sport struts like M030 ROW or PSS9s and I think it is far less critical than most drivers believe. Body roll adds forgiveness of driver input errors which is a good thing when just learning performance driving. Sways are used to do a final balance on the car.

All things in good time. For now just run good quality street tires (Hankook V12s are perfect), a performance alignment, good brake pads, fresh fluids, and seat time with an instructor. The rest will unfold as you progress.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Old 08-15-2012, 09:46 AM   #5
Registered User
 
Join Date: Jun 2012
Location: Where there is no road course
Posts: 91
Garage
Quote:
Originally Posted by Topless View Post
I suggest leaving the sways alone for now. After a year of performance driving you will totally "get" the rear sway bar change. Body roll is best managed with sport struts like M030 ROW or PSS9s and I think it is far less critical than most drivers believe. Body roll adds forgiveness of driver input errors which is a good thing when just learning performance driving. Sways are used to do a final balance on the car.

All things in good time. For now just run good quality street tires (Hankook V12s are perfect), a performance alignment, good brake pads, fresh fluids, and seat time with an instructor. The rest will unfold as you progress.

Thanks again.

I do hang out in Fontana and/or Ontario, CA for a week in May of most years (Tour of California bike race). I may have to come down in the Boxster next year and hit you up for driving lessons

Have a great week.
Boxster586 is offline   Reply With Quote
Old 08-15-2012, 04:36 PM   #6
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
Garage
Quote:
Originally Posted by Boxster586 View Post
Thanks again.

I do hang out in Fontana and/or Ontario, CA for a week in May of most years (Tour of California bike race). I may have to come down in the Boxster next year and hit you up for driving lessons

Have a great week.
Any time!
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
Topless is offline   Reply With Quote
Post Reply



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 03:49 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page