bushings

[Devilthe0ry]

hey guys whats up first post lol ANYWAYS lets talk business here i was wondering for a little bit of information between poly and rubber bushings. its for a 2009 pontiac g8 gt. idea is tighten up the response for the g8 and keep its original functionability as a dd. so best of both worlds. from my understanding, poly tightens up response but they usually last considerably less than rubber and makes noise, although the other people say they can last as much or even longer is lubricated properly. also wear and tear can cause the poly bushings to warp and deform causing the cars reaction to become lazier over time. so whats true whats false and whats what



in addition to that, im looking to add a rear sway bar lowering springs (1.4 in front 1.3 in back) and koni adjustable shocks to kill off body roll and obviously run good tires

any suggestions?

[77thor]

... from my understanding, poly tightens up response but they usually last considerably less than rubber....

You have that backwards... poly bushings will just about last forever and rubber doesn't last. Heat and vibration will eventually destroy rubber.
Also, Poly will squeak if not lubricated properly. They must be liberally lubricated during installation.

... also wear and tear can cause the poly bushings to warp and deform causing the cars reaction to become lazier over time.

Nope. Poly bushings will not warp.

[Schwartz Performance]

Poly bushings can squeak if not lubricated properly. This can also cause them to warp and deform. Google polyurethane bushing deformed and you will probably see a lot of cases. Typically this is from poor lubrication, or an application that has a lot of constant pressure on the bushing. My 6 year old sway bar end links are deformed a bit if I loosen them.

Rubber can also squeak though . If Delrin is available for your application it'll give you better wear resistance and life. But it's also more expensive and not as well of an insulator as poly and rubber. Delrin will also allow more freedom of movement, as rubber will bind and acts like a rubber band. Might not hurt to get on the G8 forums and see what others have had good & bad luck with on specific applications.

-Dale

[Devilthe0ry]

so if lubricated appropiately they could last? should i swap all my bushings to poly?? i keep reading the g8 board and theres alot of back and forth on it. alotta people like it alot of people dont but then again not everyone is lookin at the overall package value for the bushings as i am because i want to daily drive mine and take them to the track too

[Norm Peterson]

Lubrication is not the only thing involved. Poly can cold-flow over time, and it may not always recover from distortion as fast as rubber does. It'll feel "firmer", but in my experience it isn't "harsh".

Polyurethane does not very well tolerate rotation about any other axis but the bolt axis that goes through it, so you'll want to see how the links really move about the various pivots. In terms of handling, when the poly is forced to "squish" slightly to permit the suspension to move, it will generate some amount of resistance (aka "bind" even though the suspension will still move). Delrin is even worse, as it is an even more rigid material. In plain cylindrical form, these materials are best used where the 3-D pivoting remains either concentric or parallel. When it isn't, you develop additional roll resistance that's similar to making the rear sta-bar somewhat stiffer, and this can mean appreciably stiffer.

Poly can be modified somewhat to relax it's resistance to off-axis rotations, and I'm pretty sure that some (most?) of the pivot bolt axes of the Zeta rear suspension are neither parallel nor coaxial to each other or to the arm or link 3-D rotation. At the OE level, dealing with bushing "bind" has used a "voided bushing" technique, and just like it sounds the bushings are no longer completely solid. Maybe some of the available poly bushings for the G8 use this approach, but I really don't know. This is still something you could DIY though, and IMHO poly bushings should be considered "wear parts" anyway.

A few months ago I'd have sent you straight to Pedders, but it seems that Pedders USA and the main Australian HQ are currently embroiled in some sort of legal hassle and nobody here is getting or hearing anything. But there is still a ton of detail information on the at least generally similar 5th gen Camaro over on Camaro5.com, posted by member "JusticePete", who is unfortunately unavailable for reasons involving the legal commotion. "The Book" in particular may be what you want to look at. IIRC, there are three levels of bushing design for at least one type of bushing (going off memory, I think it's the cradle bushings, with bushing fillers, replacement bushings, something even more solid as options). Pfadt and BMR are also in the game with bushings and assistance with things like alignment recommendations, but not as much information as Pedders.


Norm