Bushings
 

From what I have read in the forum, the suspension bushings that cant be replaced with a plain bushing, poly or otherwise are: both rear tow link arm bushings, rear upper control arm (tire side) and both outer lower control arm. Are there other bushings that are pillow balls encased in rubber that can be replace with the higher durometer mazdaspeed or with stock in the suspension that are necessary for the multi-axis articulation of the suspension? I bought the Superpro Kit for all others.

TIA

Jpr

Well, opinions will be all over the map on this one. I can say, with my almost completely stock car with Bilstein B6 shocks and 245/45ZR16 Toyo Proxy RA1 tires, over many years, I have tracked the stock bushings, Super Pro bushings, and now currently the Mazda Comp bushings. All the bushings, front and back, were replaced at the same time as well as the pillow ball bushings each time . I can say, with my limited track time, that the Mazda Comp bushings provide the best over all handling and most predictable response. My theory on this is, like you said, many of the rear and one of the front bushings rotate in multiple axes. Some of the stock and Mazdaspeed bushings have been engineered to have different stiffnesses in each of these axes. For a polyurethane bushing you can only select one stiffness for the urethane material i.e. you can only optimize one axis. The others may not be ideal. Just a theory, but bottom line my stock car is more predictable in transitions (Cotton Corners at Button Willow and turns 3,4,and 5 at Willow Springs), and the car seems more settled in high speed turns like turn 8 and 9 and Riverside corner. On another note, with Mazdacomp bushings, at Button Willow coming out of the Sweeper I can floor it all the way through the Esses fully using the raised apex shoulders to almost completely straighten out this bit of track. When attemting to do this with Super Pro bushings the rear end shifts around so much I lose my nerve going flat out.
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