J bar length

[racing_kid]

Will a shorter or longer j bar let the car roll on the rr harder, if mounted on the same spot on pinion

[MasterSbilt_Racer]

That's a loaded question. Short can bind things up and become your main suspension link if you have too much angle. Then it kills roll and traction. If the j bar is what is causing your car to roll, shorter can make it roll more.

In general, I am very much against short panhard bars, especially mounted on the left side of the car.

[hpontap]

The shorter the bar, the quicker the reaction. But I am not sure that it actually loads the RR tire any harder.