New S14 bumpsteer graphs

[Epstein]

My data was taken with the Maximum Motorsports single dial / hinged setup.

Yeah, the hub/knuckle rolls forward pretty good as you sweep it up through the range. Even more if you're running a short traction arm. I'm wondering what that roll equates to. If you projected a line forward, swept the assembly up and down, and watched where it converged... would this point be... the instant center?

[Jason M]

I have not plotted the rear spindle fore & aft movement, but I have plotted the spindle roll angle on the s13 subframe. It is right around 3*/inch & very linear. I believe the roll may be accelerated on the s13 subframe due to the higher amount of antisqaut. I would be interested in seeing the spindle roll angle rate on an s14 subframe.


I believe that the higher amounts of antisquat may attribute to higher amounts of "roll steer", or fore & aft movement of the spindle. The roll steer that I'am refering to is the wheel base change during body roll.

Something else that we have not discussed is the setback amount of the toe rods outer pickup point vs the inner pickup point. As the spindle rolls forward under bump, the toe rod pick up points align. This setting/adjustment is similar to moving a steering rack forward or rearwards in a chassis to change the bumpsteer curve. It can be changed with lca's that have inner rod ends, and by modifiying the spindles toe rod pickup point. If the spindle roll rate is different on the s14 subframe, it would produce a different curve if the toe arms pickup point setback was left the same.

[godrifttoday]

Just messaged Epstein for the excel file anyone happen to have it? thanks!