E31/E32/E34 control and thrust arms

[Interceptor]

OK, by p/n cross-referencing, I've come to the conclusion that:
- E32/E34 share the same control (lower) arms
- E31/E32 share the same thrust (upper) arms

What I wanted to know is:
- how are E31/E32 thrust (upper) arms different from E34 ones?
- how are E32/E34 control (lower) arms different from E31 ones?

Is it possible to use E31 control arms on E32/E34, since they use the spherical bearing instead of a rubber bushing like the latter ones? I want to stiffen my suspension and make it a bit more responsive by using thrust arms with 750i bushings and control arms with spherical bearings, if possible.

This page doesn't make it very clear:
http://www.bmwe34.net/E34main/Upgrade/Suspensions.htm

[BigKriss]

yeah with that image

http://www.bmwe34.net/E34main/Upgrade/Data/controlarm.jpg

you can see the lower control arm bushing, the left item is from the e31 while the right one is the normal item. they are swappable but a lot more expensive. the upper control arms you can use 750i bushes but why not use the m5 bush instead?

[Interceptor]

you can see the lower control arm bushing, the left item is from the e31 while the right one is the normal item. they are swappable but a lot more expensive. the upper control arms you can use 750i bushes but why not use the m5 bush instead?

Why? Is M5 bush stiffer than the 750i one?

[BigKriss]

yes it is.


Why? Is M5 bush stiffer than the 750i one?

[632 Regal]

I havent even broken one yet!
Why? Is M5 bush stiffer than the 750i one?

[Interceptor]

I havent even broken one yet!

OK, thanx guys, M5 bush it is, then ;)

[Tiger]

M5 bushing is solid rubber... completely solid... whereas all other bushings is hollow at some points and 750iL has fluid inside. I have yet to put mine in... and it needs it.

[Interceptor]

M5 bushing is solid rubber... completely solid... whereas all other bushings is hollow at some points and 750iL has fluid inside. I have yet to put mine in... and it needs it.

I want a quick, defined steering response. Somehow, I think that's not possible with hollow/liquid-filled ones, so I'll try the solid ones this time :) I will be replacing the whole upper arm since the rubber boots on the outer ends are shot. :(

[Tiger]

Another choice is Powerflex thrust arm bushings. A guy in UK did this. With this, you don't have to press it in...

[Interceptor]

Another choice is Powerflex thrust arm bushings. A guy in UK did this. With this, you don't have to press it in...

A friend of mine had PowerFlex bushings on his E36, and one cracked after a few months :( I also heard they're too harsh and cause other suspension elements to wear considerably faster.

[bubba966]

A friend of mine had PowerFlex bushings on his E36, and one cracked after a few months :( I also heard they're too harsh and cause other suspension elements to wear considerably faster.

Were they the regular purple powerflex bushes or were they the black powerflex bushes?

The UK M5 guys have found the black ones to last just fine, but the purple ones can crap out after a few months.

Yes, they will be harsher/stiffer than any stock bushing. Never used them myself so I can't say how much more stiff they are than any of the OE options.

And yeah, you can use the E31 control arms with the spherical bearings in them. I don't know what difference the E31 arms will make as far as ride/handling/durability goes, but I do know they'll fit just fine.

[Tiger]

Then M5 is the way to go... I am glad I have the M5 bushings ready to go.

[Interceptor]

Were they the regular purple powerflex bushes or were they the black powerflex bushes?

Yes, the regular purple ones. I didn't even know there are black ones?

[bubba966]

Yes, the regular purple ones. I didn't even know there are black ones?

Black one need to be special ordered as far as I know as they build them to order. Firmer than the purples, but they don't crap out like the purples either.

No personal experience with either as I've got the factory setup M5 bushes in my M-Sport. And that's all that's ever been in my car.

[genphreak]

Poly ones increase road noise a lot. Even the 'softies'. I've used Grunts greens and Noltec blues without any losses. If you can afford OEM M5 ones, go for it. I'd be careful buying though, OE ones simply won't be the same ;)