hbomb2k

My 94 Formula has some clunking up front when going over bumps, inspection has revealed that the stock rubber suspension bushings are shot. I bought the car lowered on what I believe to be an eibach pro kit (purple-ish springs).

I plan to drive the car occasionally, while using it as a daily/drift car (yes I drift an fbody). Conventional wisdom would suggest go poly with everything, but I have yet to find information that is conclusive on the advantages of poly vs rubber. I want something that wont wear out and is stiff (poly) but many claim that poly bushings hinder suspension movement often so much so that broken parts will result, I certainly would rather replace a bushing than a control arm. Will new rubber last plenty long? Or does poly not bind near as much as people say?

JD_AMG

In certain locations that need to articulate in more than one direction poly will bind and has been bad enough to break control arms. Rear lcas move in multiple directions, not just up and down and the front lower control arm vertical bushing location will crack if you put poly there.
You are not the first to drift an fbody either. Throw those eibachs in the trash and get a good shock/spring combo on there and you will be blown away at what these cars can do.

sjsingle1

iTrader: (1)

I had ES poly in my arms...over 100k street miles and no arm breakage....my .02

but moog makes a fine problem solver bushing for the rear location that should be used over any other type or brand of rubber bushing

dont walk but RUN those eibach springs to the nearest dumpster

dojob

Yes, replace the with new Moog rubber bushings. The moogs rubber bushings are stiffer than the OEM rubber and without the binding issues of the poly.

Summit and Rockauto can get you the bushings at a great price. But shop around to confirm

hbomb2k

The specific pieces that need to be replaced are the front UCA bushings, and with that in mind I realize I could go poly or rubber either way, really comes down to which is cheaper, I'm a high school kid on a budget. I wanna do it right but I don't wanna break the bank either.

dojob

Sounds like you just gotta go shop for Moog's rubber bushings then.

LS1121

iTrader: (17)

I had Poly in my entire front and rear suspension for more then 150,000 miles and NEVER had anything break, my DD also. The only issue I had was the front upper control arms tend to squeak and need a lot of grease. The car drove like a slot car, loved it! I recently got tired of the hard ride and replaced all the bushings again with Moog, real nice ride now. My DD now is a Corvette so the Z28 is just for weekends mostly.

hbomb2k

Ordered a front end rebuild kit from Energy Suspension. All things considered it is actually turns out it is cheaper to go full poly than to replace everything up front with rubber. So that was my ultimate decision maker, I also think that overall for my application poly will hold together better over time. Thank you everybody for your input!

Also why is the eibach pro kit so hated? (for the record the car came to me with these springs) To me at least the car feels pretty planted with these, why exactly are they so bad?

dojob

DO NOT put the poly bushing in the rear spot of the LCA. That bushing must flex and will not be able to do so properly with poly bushing in there. Just get a Moog bushing for each of those. Peoples' LCA's have even cracked at that location due to how rigid the poly bushings are.

Eibach kits for these cars do not perform as well as alternatives and tend to sag after a period of time. UMI, Strano, BMR are better performers and offer the similar or lower ride height depending your taste

Sam Strano

iTrader: (41)

Poly in the control arms is ok some placed bad in others. Like that lower rear bushing in the front arm. Junk, will fail, and won't take long to do it. Also Poly has it's place but not where you need articulation, which is why I typically recommend all poly, and if you run poly like in a rear arm, the other end has to be something that can pivot freely. Poly is not that.

Eibach Prokit, the single biggest reason I started doing my own springs. Sold lot of Eibach way back, and no single item had more complaints, mostly about the rear height being too low vs. the front. When I made mine I took that into account but also made other changes like stiffer front for less dive and more roll stiffness.

StoneColdLT1

iTrader: (8)

I replaced all of mine with Moog rubber bushings and I used their problem solver for the front LCA vertical bushing. The problem solver is more like a ball joint than a bushing and it works very well in that spot.

IMO, if you wanted to go the poly route, I think poly would be fine for the front UCA bushings, the front LCA horizontal bushing, and maybe the panhard bar. I would definable NOT use poly for the front LCA vertical bushing and rear LCA, those need articulation which you will not get with poly.

I would recommend Moog's problem solver for the front vertical bushing and Moog's standard replacement rear LCA bushings, they are solid, just like the 1LE bushings.

JROC

Just use the Founders 3 piece poly ball joint rear LCA's. All the benefits of poly without any of the negatives. They keep the rearend in place when launching hard without any of the deflection associated with rubber but allow the rearend to rotate side to side without the binding associated with poly. The price is right also. I've been running them for over 1.5 years with no issues. Other than being a little bit of a PITA to install they're great.
https://www.foundersperformance.com/...r-control-arm/

You can also buy them as an adjustable C/A.
https://www.foundersperformance.com/...ble-poly-poly/

Sam Strano

iTrader: (41)

You know how you must lube poly on metal? Because Poly is sticky. Put poly on poly and it's even more sticky. Not a great idea in practice.

hbomb2k

I did a full Hyperflex kit up front, and yes even the front rear lca bushing. I opted to go poly on that bushing despite my doubts because the Hyperflex kit uses a 3 piece bushing in that location with a very similar design to the 3 piece founders rear lca bushing (which are proven to work well). After install and no springs/shocks the entire assembly moved up and down with significantly less effort than was required with completely shot rubber bushings. Instead of using the included grease (which is a lithium based NLGI 1 grease), I opted for a lithium based NLGI 2 grease that I picked up at the parts store. Certainly seems like it will keep things moving nicely for a lot longer than that light grade included grease. Can't wait to get to actually drive it, (waiting on getting an alignment).

Zlow28

iTrader: (11)

I never liked poly on my car so I replaced most of it with moog rubber bushings. However, poly isnt all junk either. It wasnt necessarily a day and night difference between the two, but what I couldnt stand from the poly was the squeaking noises it would make. Specially in winter time. Id have to go in and grease them pretty often. Not really hard to do with grease fittings, but pretty inconvenient.

I think the only poly I have left on my car are the bushings from stranos sway bar, and my rear bump stops. They havent been an issue tho.