Driving Impressions: Lower Stress Bar - 986 Forum - The Community for Porsche Boxster & Cayman Owners

insite · 04-23-2007, 08:34 AM

the lower stress bar was designed to jack the subframes apart and hold them that way during driving. the result is that camber is maintained during hard cornering. most people thing that addition of an upper strut tower brace on this car is helpful. the problem at the rear is not the top of the strut towers, it's the bottom of the subframe. when you turn, the outside control arm is pushed toward the center of the car. this causes chassis flex and camber loss. here's a picture of the solution (i call it the ernie bar):

insite · 04-23-2007, 08:36 AM

install was a snap. i removed the nuts that fasten the diagonals to the shear plate. i pounded out the studs with a hammer. i test fit the ernie bar to set its length, then installed it permanently. piece of cake; takes about 15 minutes once the car is jacked up:

insite · 04-23-2007, 08:40 AM

impressions: this thing is great! i wasn't sure how much i'd notice it. i went to the track last monday and put it to good use. from the driver's seat, the car seems to set much more quickly on corner entry (a perception reinforced by swapping drivers and boxsters). from a measurement perspective, i was pulling significantly higher lateral acceleration numbers than i ever have. in the mildly banked corners, i was at 1.3 g's. in the unbanked corners, i was between 1.15 and 1.2G's. this was on STREET tires. once set, the car also seemed less prone to unsettlement over bumps. the car just doesn't seem to flex as much in back. here's one lap of telemetry:

insite · 04-23-2007, 08:45 AM

bottom line: this thing was like $130 shipped. it really works! between my last track day and this one, i did the following:

996 front brakes w/ racing pads
mantis lower stress bar
bilstein sport front dampers

lap times went from 1:15:20 to 1:12:72. that's 2.5 seconds on a 1.41 mile course! i'll take it.

chaudanova · 04-23-2007, 09:39 AM

wow, thanks for posting this up, that's awesome to hear. Do you know what G's you were pulling prior to the addition of the bar? And also, do you notice any difference on street driving?

insite · 04-23-2007, 10:09 AM

Quote:

Originally Posted by chaudanova

wow, thanks for posting this up, that's awesome to hear. Do you know what G's you were pulling prior to the addition of the bar? And also, do you notice any difference on street driving?

on this course, i averaged 1.06G with a max of 1.13G. this thing put me in the stratosphere here. it really holds the camber. as for street driving, it doesn't effect comfort levels at all. i don't really notice it under normal driving circumstances. it's very noticable when i push it.

BobMarley1 · 04-23-2007, 10:27 AM

how do I order one?

blinkwatt · 04-23-2007, 10:33 AM

Does the company that you bought the stress bar from have a website?

*Never mind I found it;
http://www.mantissport.ca/
I can't seem to find the lower stress bar though.

edevlin · 11-03-2007, 02:11 AM

"since they have now over one year of experience racing the Cayman platform, i asked what they've found a need for and what they've installed on their car. in addition to a host of other stuff, Ernie mentioned a lower stress bar to me. "

I have put off getting one of these because I was going to make one, but have not gotten around to it, so I plan ordering one next week. In addition to the stress bar, what other things have you done to tune your suspension, thanks,

Ed