Torque Arm

[dewittpayne]

But do you want a low rear roll center for autocross? Moving the roll center up or down also changes the balance of the car. When you lower the rear roll center, you increase grip in the rear and lower it in the front, i.e. you make the car push more.

I want a lower one than stock on a 79-04 Mustang. And I want to increase rear grip.

The major problem with the rear suspension of 79-04 Mustangs is not the height of the roll center, it's the four link suspension that requires soft bushings to prevent binding. Weld in subframe connectors, put in proper lateral location with a Watts Link or a Panhard bar parallel to the ground at static ride height, replace the two top links with a torque arm underneath (converting it to a three link suspension) and replace the lower control arms with ones with better bushings and you have a much better car. It will also have a lower roll center, but that's a consequence, not an end in itself. It will also plow like a Deere tractor unless you increase the rear spring rate substantially and/or lower the front roll stiffness. Maximum Motorsports claims that there is a preferred roll center height with their torque arm. With their Panhard bar and mount, there is a fairly small ride height range that allows you to keep the Panhard bar parallel to the ground.