I have read many opinons on where to place the rack spacers and they are in-fact just opinions. I have an alignment rack at work sooo, time to end the debate. Here is the sum-up:
SPACERS UNDER THE RACK-- this yeilds an incredible amount of bump-steer. Somwhere around 1.5 degrees in about 3" of upward and 2" of downward movement. PER SIDE! So if you set the toe at 0*, when you raised the car 4" it would be 1.5* and the opposite when lowering. 5-6* of toe change per side per suspension sweep. Unacceptable.
SPLIT A SPACER ON TOP AND BOTTOM OF RACK-- long story short this yeilded a bit less than 1* when moving the suspension up 4" and close to it when sagging. Again starting from 0* toe at normal ride height. Still unacceptable.
INSTALL THE SPACERS ON THE TOP OF THE RACK!!-- When doing this, the most I could get the toe to change per side was around 20min up and 20min down. 40' through the my full sweep (4" up and 3" down from my ride height) 40 min is just over half of 1 degree. IMO this is still barely tolerable but it is certainly the best of the 3 options.
I haven't driven the car too far since changing it. I have thrown it through a few bumpy turns and it is more stable. Oh that reminds me, I ran my little test with the steering wheel turned 180* just to see if that affected the measurements. It didn't.
I have H&R sports w/ e90 drop hats, so my car is not too low.
SPACERS UNDER THE RACK-- this yeilds an incredible amount of bump-steer. Somwhere around 1.5 degrees in about 3" of upward and 2" of downward movement. PER SIDE! So if you set the toe at 0*, when you raised the car 4" it would be 1.5* and the opposite when lowering. 5-6* of toe change per side per suspension sweep. Unacceptable.
SPLIT A SPACER ON TOP AND BOTTOM OF RACK-- long story short this yeilded a bit less than 1* when moving the suspension up 4" and close to it when sagging. Again starting from 0* toe at normal ride height. Still unacceptable.
INSTALL THE SPACERS ON THE TOP OF THE RACK!!-- When doing this, the most I could get the toe to change per side was around 20min up and 20min down. 40' through the my full sweep (4" up and 3" down from my ride height) 40 min is just over half of 1 degree. IMO this is still barely tolerable but it is certainly the best of the 3 options.
I haven't driven the car too far since changing it. I have thrown it through a few bumpy turns and it is more stable. Oh that reminds me, I ran my little test with the steering wheel turned 180* just to see if that affected the measurements. It didn't.
I have H&R sports w/ e90 drop hats, so my car is not too low.
Comment