Rear upper control arm bushing recommendations

2QUIK6

Turbo Milk Jug displacmnt
Joined
May 28, 2001
I've already got poly bushings in the lower rear CA's, what's the recommended bushings to use on the upper rear CA's?

I'll be removing them to box them in soon and want to replace them while they are out, or are the stock ones recommended for ride or binding etc..?
 
I've got a set of never installed HRpartsnSuff poly bushings for the rear end housing (the little eyelets on top) I bought them and didnt end up needing them. Let me know
 
Definitely recommend the HRpartsNstuff bushings :)

Actually, we make the only poly replacement bushings for the rear housing and control arm ends that have a grease fitting on them. There are other special features, but that makes them binding & squeak free. We got the only custom tool to take them out of the rear hsg and install new ones with too. Got to make it easy :) Check out the products section for details if you are interested.
 
Originally posted by HRpartsNstuff
Definitely recommend the HRpartsNstuff bushings :)

Actually, we make the only poly replacement bushings for the rear housing and control arm ends that have a grease fitting on them. There are other special features, but that makes them binding & squeak free. We got the only custom tool to take them out of the rear hsg and install new ones with too. Got to make it easy :) Check out the products section for details if you are interested.

Used them on my car very pleased :) , Great product and company.


Jesse :cool:
 
I used brand new stock rubber bushings. I do so on Geno's recommendation as he ran those into the 9's on stock boxed uppers. If they're good enough for his 1.36 60's there good enough for me. :D :cool:
 
Paul, I was planning to get the box kits from you already and have looked at your poly bushing.

The reason I was asking was because it seems like I had read somewhere that poly uppers caused some binding on the rear end, but can't remember the details???
 
Greetings Paul Ferry,

What's the durometer or Young's modulus of the PU material you use? I ask because there's a very broad range of material properties available for polyurethane, and I've heard (though can't verify personally,) that the high deflection stress induced at the upper control arms with significant suspension travel, which is amplified by the short length of these arms, and the high stiffness of PU vis-a-vis the factory rubber material, has on at least one occasion caused the bushing ears to literally break-off of the differential case.

Best,
MAP
 
First of all, our poly bushing design won't bind or squeak like other "more common" poly bushings for 2 reasons:

The design incorporates a grease fitting that allows grease to get to the inner sleeve, 360 degrees around and the full length.

The inner sleeve is ground down to a special dimension, allowing less resistance on the poly. This is a small amount, but it makes a BIG difference. The arms will move smoothly up & down (for suspension travel & weight transfer), but are still tight side-to-side for handling improvements. Our bushings will move easier & smoother than even the new rubber bushings from GM.

As far as durometer, not exactly sure. It is around 90 I believe. It is stiff enough to handle hard launches, yet gives enough to make it a nice ride on the street. For those looking for 60 ft's lower than 1.40's, we recommend adding a delrin center to the lower CA's. This is "basically" a hard plastic that has high lubricity characteristics and can handle high impact & load. Some use this material all the way across, but we found it works best & is plenty strong enough just using it in the middle. Makes for a harder ride, but can't get it all when in the 1.3's & quicker getting the most out of it. We have been doing this for a short time now, and unfortunately don't have the info on our site yet. I see how fast each person plans to go & treat each person as a custom application. One size doesn't really fit all if you are looking for the most from your combo.

Which brings me to my last point. NOT to take anything away from Geno's efforts or results (because they are quite amazing), but he should really be in the low 1.3's when running 9's. My car went a 1.401 60 ft time (which is really close to a 1.399) going 10.80's. I would think my 60's would have been low 1.3's minimum if I had more power to shave close to a full second off my time (that would have been nice :) ). My point is, there are a few people that go fast with stk suspension parts, but it is not real common. I believe they could knock a few tenths off the 60 with the right stuff (our stuff :) ), which would have been 3-4 tenths on the 1/4 mile time. Of course I can't imagine mid 9's on a stk block, but that shows it could be possible, unless it's too violent for the block to handle. Good working suspension will allow you to find the weak link because you can keep hitting it harder & harder.

As far as breaking the ears off, I have only heard that happening on install/removal WITHOUT our tool. It was common years ago (& somewhat today) to have a solid aluminum "bushing" in there for racing. If it binds enough to break the ear off, your rearend is nowhere close to being under the car. Jack the car up from the rearend center, support the frame, and lower the rearend. The arms don't get too far out of alignment from the ears, even at full travel. There should be no change side to side, or your tires will rub the frame & wheel openings. There is still some, even with our CA's, but nowhere near enough to break an ear off. The side-to-side motion is one more thing solved with our new swaybar/anti-roll system. It takes a lot of unwanted stress & resistance off the suspension (and ears) by keeping it square with the chassis, but that's a whole different topic :)

Hope that helped explain things & answer questions.
 
Greetings Paul,

Thanks for that detailed response. Is that 90 durometer Shore A or D, incidentally? About PU bushings being made to move more easily than the factory, I believe it. Rubber bushings move primarily by shear strain, whereas PU bushings slide and therefore exhibit viscous loss (primarily) when greased.

The 60' times you quote are impressive! If I could only figure out how to do that while not compromising road handling (1G minimum or bust,) I'd be a very, very happy camper indeed.

Best,
MAP
 
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