Recommendations on bushings

[John@Revshift]

SkiFree has is right.

UMHW has very poor compression set. This means that when it is deformed it does not return to its original shape and size. If you hit UMHW with a hammer it will dent. Most types of polyurethane used for automotive bushings have good compression set characteristics which means they return to their original shape after being deformed. Hit polyurethane with a hammer, no dent!

The 75D polyurethane that we use has a higher tensile strength than UMHW as well.

As was said before, UHMW is cheap and easy to machine. It is a poor choice for automotive isolators because it has poor physical properties. You can search the internet for general physical properties of both materials and see for yourself. The scientific data doesn't lie.

Just to be clear, what I am saying is not brand marketing. I just want to get the facts straight. I like polyurethane for a bunch of reasons. I think it is a great material for aftermarket mounts and bushings.

[SkiFree]

Every automotive engineer I've ever spoken with has always stated that poly is a poor materials choice for automotive bushings, because it can deform on impact, and not rebound like rubber.

Well for starters this is incorrect (and I know of several race teams using poly in varying applications). Perhaps you were misunderstanding what they were saying but polyurethane is a variant of rubber (Your description of deforming and not rebounding is actually a common characteristic of UMHW).

RUBBER is also known as a "THERMOSET ELASTOMER" and Polyurethane is a VARIANT of RUBBER. UMHW is a THERMOPLASTIC and falls under a different umbrella.

If you take my advice and want to learn more rather than rely on others then this is a good place to start.

http://www.makeitfrom.com/material-data/?for=Polymeric

If you want information on materials as they pertain to E30 bushings/mounts then you're inviting more brand marketing and personal opinion (which isn't a true understanding, it just sounds cool to repeat to buddies at car shows). Yes, I have real-world reasons/experience for not using umhw, but this would only continue forum "debate".

[kendogg]

It's not an argument for engineers, the only arguments are between people without a full understanding of what they are talking about and those financially vested in it (and it's not an answer that can be easily answered by simple forum posts [basically depends on usage, cost, and life span.]). If you'd like to learn more, I really suggest starting with a basic understanding of the limits and abilities of Thermosets and Thermoplastics.

Financially, UMHW is a God-send as it is MUCH cheaper than the cost of urethane so the profit margin can be VERY very healthy.

Well, how about we start with the fact that I'm not aware of a single OEM that uses poly, nor a single pro race team, in any application. Every automotive engineer I've ever spoken with has always stated that poly is a poor materials choice for automotive bushings, because it can deform on impact, and not rebound like rubber. Hence my request for John@Revshift to expand upon his comment.

[LoneWolf]

But it is in no way an adequate replacement for a weld-in setup. Ask any decent spec-racer, race-prep shop, etc...... including Condor.

Adequate? You mean not adequate enough alone to get ride of the camber?

I imagine a racer would want the adjustability of the weld in kit. Or is it also necessary on a street car?


Should be getting ground control coils soon and I'm looking to do it all at once. Do I need the weld in kit for sure too?

[SkiFree]

The condor 12mm subframe bushings are made to raise the subframe 12mm to take out some of the camber from lowering the car.

But it is in no way an adequate replacement for a weld-in setup. Ask any decent spec-racer, race-prep shop, etc...... including Condor.

[SkiFree]

Would you mind expanding upon that? Interesting you say that, because thats one of the biggest engineering arguments against poly vs rubber.

It's not an argument for engineers, the only arguments are between people without a full understanding of what they are talking about and those financially vested in it (and it's not an answer that can be easily answered by simple forum posts [basically depends on usage, cost, and life span.]). If you'd like to learn more, I really suggest starting with a basic understanding of the limits and abilities of Thermosets and Thermoplastics.

Financially, UMHW is a God-send as it is MUCH cheaper than the cost of urethane so the profit margin can be VERY very healthy.

[LoneWolf]

Yup, I think they all did it. The old K-Macs loosened up often on people, and so did my AKG's. Even if I did the weld-on kit, I'd stick to OE rubber rtabs these days, even for a track car.

The condor 12mm subframe bushings are made to raise the subframe 12mm to take out some of the camber from lowering the car.

[FLG]

Condor bushings all the way. For some the engine/tranny mounts are a bit harsh but the rest of the stuff could be used on a daily without much thought.

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[kendogg]

The difference is that the uhmw stuff doesn't rebound like polyurethane and it will deform over time. 75D polyurethane is solid and will last FOREVER! :D

Would you mind expanding upon that? Interesting you say that, because thats one of the biggest engineering arguments against poly vs rubber.

[John@Revshift]

Looking to replace all the bushings on my car (except for motor, trans, and the sway bars) and was wondering anyone had any recommendations. The other question I had is what would that cover? I wanted to make sure that I purchase all of them in one go so I don't have to reorder later because I missed something.

So far I've looked at Powerflex and Revshift. Powerflex seems to have everything but is considerably more expensive, and Revshift is cheaper but it looks like they only have a kit that covers the rear (diff, arms, etc).

Any info would be greatly appreciated, I'm trying to change out everything and freshen up the beast in one go.

We offer front control arm bushings as well. I believe you are looking for the diff bushing, rtabs, subframe, and front control arm bushings. There isnt anything else that you can do other than motor/trans mounts, guibo, and sway bar bushings.

We offer them in 80A (soft), 95A (hard), and 75D (solid). The 75D is comparable to white nylon/uhmw bushings that you see being sold on the forums. The difference is that the uhmw stuff doesn't rebound like polyurethane and it will deform over time. 75D polyurethane is solid and will last FOREVER! :D

[kendogg]

I thought I remember reading some people having trouble with those adjustable kits for their cars? Like they were slipping out of alignment or something. Couldn't get the bolts tight enough I guess?

Just thinking if those subframe bushings from condor get ride of the camber added by lowering the car without having to make any adjustments, that could be nice. Just wonder how they make the ride.

Yup, I think they all did it. The old K-Macs loosened up often on people, and so did my AKG's. Even if I did the weld-on kit, I'd stick to OE rubber rtabs these days, even for a track car.

[mr.bennett]

It's not bad at all really. I put it all on at the same time but I think I get more noise and vibration transferred from the diff mount then the rtabs. This is my daily for right now and I've got around 10k miles on the suspension without any real complaints.

I noticed a lot more vibration and noise transfer from swapping the tranny mounts a couple months ago then I did from the complete suspension overhaul.

[LoneWolf]

I haven't followed some of this in awhile, can somebody point me to the direction of what exactly these Condor 12mm subframe bushings are? Thanks.

Truthfully - for a purely streetcar, you might as well get the adjusters. Dial out some fo the camber, and most of the toe. Bear in mind, it'll drive like crap, but your tire wear will be fantastic, and you might even gain a half a mpg. Otherwise, unless you're trying to correct a problem for some reason, I wouldn't worry about the adjustors. I had AKG adjustable subframe bushings in my first E30 trackcar, and you know where the race alignment shop set the rear camber & toe - barely a hair off stock. Just not worth the effort & expense IMO.

I thought I remember reading some people having trouble with those adjustable kits for their cars? Like they were slipping out of alignment or something. Couldn't get the bolts tight enough I guess?

Just thinking if those subframe bushings from condor get ride of the camber added by lowering the car without having to make any adjustments, that could be nice. Just wonder how they make the ride.

[LoneWolf]

they raise the sub frame up 12mm relation to the body to move the trailing arms to help correct the camber issues. All my bushings are condor i have the 12mm risers and m3 offset cab with ground control coils. My car had 2 deg. camber in the rear at this ride height

You're running the exact set up I would like to.

But being a street car I am thinking rubber RTABS.

How does it feel with all of the condor stuff?

[mr.bennett]

they raise the sub frame up 12mm relation to the body to move the trailing arms to help correct the camber issues. All my bushings are condor i have the 12mm risers and m3 offset cab with ground control coils. My car had 2 deg. camber in the rear at this ride height