Originally Posted by
AzFittin
Okay time for one that I hope is not a mystery to someone out there.
I have been running my mini for over a year with good success but always had an issue where the rear end will start wiggling side to side once it reaches top speed on a straight. Typically it is just an annoyance but on occasion the wiggling results in a fairly strong turn to one direction or the other. It only happens once the car is at top speed, any acceleration keeps it under control.
I have adjusted the front toe both in and out to varying degrees and found zero, oddly, to work the best. The rear is stock toe. I have adjusted the camber from zero to -2.5 and seen no difference. I have tried various tires, treaded and non, front and rear and seen very slight changes in the behavior (brand new s-grips on the rear with slicks on the front seem to be the best). Track is a medium size parking lot with soda so traction tends to be very good.
I have not tried adding weight but have changed spring rates, oil weights and shock positions with no luck. I have also changed ride height front to rear and found lowering the rear slightly to bring it level with the front does help the rear but I lose so much steering it is not worth it.
Thanks for any thoughts and please let me know if there is any more info you would like.
Jason
How much shock travel are you running? Sounds a bit like the rear is running without any droop, so the springs are pre loaded. This may explain why the car is stable with a lower rear ride height. Try lengthening the rear shocks so you have 0.5 to 1mm shock extension when you lift the car from its ride height.