| RE:Rear Suspension Fabrication |
Subject: RE:Rear Suspension Fabrication by ghoffman on 2008/1/27 17:51:54 We have those Hyperco spring perches and they are very nice. All coils have a "sideways" mode and you can see its' effect after a while on the shock due to the spring hitting the shock in many cases. The Hyperco perches allow the spring's to operate in a condition that any moment at the ends is eliminated and this helps the shock's seals and bearings last longer. I think for this application it is not necessary especially with the way we do our dual rate spring package. What we do with our dual rate coilovers is totally different from the tender spring mentioned by Bill. With ours, the lighter spring is not coil bound at ride height but becomes that way after some travel, and allows a softer initial rate with a much higher final rate. This rising rate dramatically improves compliance and grip over ripple bumps, gators, expansion joints, etc, while reducing bottoming on heavy transitions like we have at NHIS or Lime Rock. In addition, the custom 2.25 inch poly spring coupler we make acts like a guide for the springs and saves the shock body's threads from getting hit by the spring. In the case of the C5 and C6's, the rear motion ratio changes from full droop to full bump in a regressive way. Ideally, you would want it the opposite way, i.e. a rising rate (like a pushrod/rocker setup in a Formula car), but since the shocks are angled over and the angle gets less and less, it requires a much stiffer spring that you would normally want. The dual rate setup compensates for this to a great extent. Here is a pic of the Penske 8760 3 ways for a C6Z and you can see the red poly coupler. Also note the small setscrew near the Heim joint, that is the newest version of the rebound adjuster. All you do is stick in there a ball driver, and it has 6 "clicks" per turn, 4 turns total. Very easy to do on the car by just turning the wheel to one side.  |
