Body Mounts...Rubber or Poly?

[83hurstguy]

At some point, I'd start shifting my attention from overall chassis stiffness to places where abrupt changes in stiffness exist. For a full-frame car, one such area would be the frame rails at the body/frame attachments closest to the firewall. You go from [combined frame + body] to just [frame] over only half the length of the body mount.


Norm

Definitely. You can really maximize torsional stiffness gains using this method. When we were going FSAE chassis work back in my school days, we had the chassis in Ansys and would try to look at data of deflection vs. longitudinal position to find where the most deflection was coming from (of course, on these cars it can be fairly intuitive). General rule of thumb we used in optimization was to have the chassis an order of magnitude stiffer than the difference in the front and rear roll rates. This would allow the chassis to be tuneable with the suspension.

Anyways... overkill for this thread, lol...

I put poly's in my T-top H/O and love the way the car rides. The rod ends in the rear UCA's put a little more rear end noise into the car, but it's not too bad. They were very cheap too.