Rear control arm bushings

[Algershick]

There are a ton of bushing combinations all over every G body/hotrod forum on the Internet. Different opinions, contradictions, no different than politics.

I'm building my car for street and spirited driving. I want a sporty predictable ride, but I don't want to rattle my teeth out either. My frame is boxed, control arm braces installed. Rear LCA's will be boxed, haven't decided on uppers yet.

I'm looking to be in the neighborhood of 400ft lbs of torque. From a rear suspension standpoint, what bushing combination makes sense? I've read poly on both ends of the lowers, and 1 end of the uppers with a special bearing at the other end. Does it matter if the poly is at frame or differential side?

I'd really like to hear your preferences and why. Thanks!

Austin

 

[pontiacgp]

You can't box the uppers. I have the UMI uppers with a roto joint and poly bushing in the rear, I grease the roto joints when I store the car for the winter and after 3 summers no problems with them..I have the UMI custom lowers with a roto joint on the rear end to compensate for the angle with my A body rear end.

 

[Algershick]

I could have been more clear, I understand that the uppers can't be boxed. That at least has been pretty consistent across most forums! Thank you, though.
Would you say that 1 roto joint in the lowers is necessary even with an 8.5 and factory control arm mounts?

 

[pontiacgp]

if you have the G body rear you won't need a roto joint in the lowers.. UMI was nice enough to modify the lowers to put a roto joint in for my situation.. Even thoughtmy A body rear is wider than a G body rear the bracket for the lower in further inboard than the bracket on the G body rear

 

[Algershick]

I've read about your setup in quite a few threads, I appreciate the pic.

Is poly then okay to use on both ends? Is there a reason that poly is acceptable to use in the rear, however people are opposed to using it on the front end due to binding?

 

[autonaut]

Cant really advice you based ob experience but i have always used rubber all around. Only place i use poly is sway bar end links, and body bushings.

Unless you're autocrossing the thing i doubt you'll notice much other than increased NVH going with poly for the a arms.

But again. I haven't tried your proposed combination. Just stating rubber bushibgs will take you a long way in a solid rear car..

 

[pontiacgp]

I've read about your setup in quite a few threads, I appreciate the pic.Is poly then okay to use on both ends? Is there a reason that poly is acceptable to use in the rear, however people are opposed to using it on the front end due to binding?

I have poly in the front of the lower control arm, the deflection of the lower control arm as it moves is extremely little. The lower control arm is much longer then the upper so it's defection is much less than the upper.

 

[Algershick]

Good information guys, thanks.

 

[ssn696]

If comfort is at all in the plan, stay with rubber - find high durometer like GM used in the GN suspension. Moog Problem Solvers may be that type.

 

[UNGN]

A big sway bar in back helps reduce under steer, but will crush the factory LCA's and tear the cups out (even boxed ones). Beefy Aftermarket LCA's with poly will be fine with a larger bar for normal driving and the occasional autocross. A big sway bar will make the rear travel less and keep it out of big deflections where it REALLY binds (not just stressing the bushings bind but locked up with no more travel and one tire off the ground binds)

With a protouring style rear bar you can get away with boxing the factory arms, but not with a bar bolted to the arms. It will work for a while, but eventually everything will get sloppy.