full e34 suspension upgrade

[originalMJG]

Hi everybody, ive spent ages searching for the info but found nothing so please go easy on me if its a re-post.

i am aware that there is an aluminium suspenion arm that is a bolt on fitment from the e34, is this the track control arm or the other one, the lower control arm?

anyway, i would be interested in this swap, but is there any reason why the hubs, steering arms (if the track width becomes any different ), and therefore the front suspension strut cannot be swapped over?

and i think i read that the e34 trailing arms fit, and they are gusseted are they? (this may be the later model e28s, ive forgotton now (@) ), but does the entire rear beam fit?

also, is it only the length of the rear suspension strut that makes it unsuitable? it appears that the e34 suspension is more common so would be easier to source.

really am sorry if this has been covered but i would like a definative answer and i havent been able to find it. i am at the stage where any serious beneficial suspension work would be possible providing its not too expensive.

thanks!

[rexmo]

As far as I'm aware, you're in uncharted waters here.

The parts that are known to be able to cross over to the E28 are the steel or aluminum lower control arms, the bushings for the upper control arms if milled to fit the narrower slot on the E28 subframe, the gusseted trailing arms, and possibly the dogbones.

I can add to this list the upper control arms, I have E32 UCAs on my '87 535i.

I think that., at least in front, the strut bearing/mount is significanntly different. The E34 front subframe is a tubular design. The rear subframe hasn't been made to work, as far as I am aware, and if it had it would be worthwhile news for the possibilities it would open up for diff alternatives.

[originalMJG]

well i dont have dogbones on my rear ~0 hahaha, mines an '82 525i (euro, since im in england).

are the upper control arms from an e34 the same as the 32?

im getting a full poly bush kit for the front end, from australia (well a friend, who has imported them from Oz), these are for an e28, will they fit the 32/34 arms?

thanks for the info rexmo and when you say the strut bearing/mount is different, you mean at the top where it hits the body?

thanks! and im glad it wasnt a complete repost. cheers.


[Edit by originalMJG on [TIME]1134320542[/TIME]]

[originalMJG]

ive done a little research, and at GSF carparts in england, their website says that the LCAs are all the same part number e28/32/34 and it lists an aluminium part for the 32/34 but says that its to replace aluminium ones only? why is this, is it that other parts were strengthened to allow a weaker aluminium LCA in later models or something?

it lists a different part number for the UCA of 28/32/34, so im guessing this is just the bush that is different? and are they different between the 32/34 as they both have a different part number.

oh and all the steering tie-rods are the same, just a note since i mentioned that in my first post. im guessing then, that the thing that makes the car wider is not the actual suspension, just the width of the engine bay part, and maybe the central tie rod is longer/shorter, and the subframe.

i cant find a part listing for the hubs, but am i right in saying that the damper struts are just inserts anyway, and that they insert into a tube that is a part of the hub? (btw im not sure if you call them hubs, the part attached to the brake disc, that connects all the control arms to the wheel in effect).

can i not use the hub/strut housing thing, and damper from an e34 for example, with the spring and top mount setup from the e28 to ensure compatibility? this is on the understanding that the tops of the dampers are just the same sort of thread and that the springs are of the same diameter.

there may be no gain to this, but im assuming the newer bmws were generally better, and it would mean that the brakes would bolt right on (or do the 34 brakes bolt straight on anyway? something keeps being mentioned about the calipers and carriers being needed, whats a carrier?)

wow im asking a lot of questions.... sorry! il stop for now.

thanks guys if anybody can answer any part of my jibber-jabber.

[Jeremy]

I can't answer close to all of that, but I do know the answers to a few.

First, the e34 brakes do indeed bolt up directly to the e28 with no modifications needed. The 540/M5 brakes are generally the more sought after upgrades. The caliper bolts attach to the carrier, and the carrier attaches to strut assembly.

I don't know about the e34, but on the e28 the various control arms and wheel bearing attach to a "steering knuckle" that's attached to the bottom of the strut tubo by three or four bolts.

I don't know the why the catalog says only to use aluminum LCAs on cars already equipped with them, but I know a good number people have used them with no ill effects.

It sounds almost like you haven't done a whole lot of work on your car yet by some of the questions being asked. Just let me say, there's really no way to make an e28 ride like an e34 that I know of. There's a lot more to it than just a different subframe and different control arms. It's a whole system which includes the chassis. In the case of the e34 that chassis is fairly heavy, which does help to smooth out the ride.

Jeremy

[originalMJG]

nope ive practically done nothing to my car yet, so id like to figure out what i could do whilst im servicing the suspension.

so would the upper control arm be any improvement over the e28? even though its steel like the original?

[rexmo]

Not sure why they changed it. The ends are in the same relationship, but the shape in between is slightly different.

[Steve Haygood]

[QUOTE="originalMJG"]nope ive practically done nothing to my car yet, so id like to figure out what i could do whilst im servicing the suspension.

so would the upper control arm be any improvement over the e28? even though its steel like the original?[/QUOTE]

thee e34 arm is made to different geometry than the e28, don'tthink it will work,,,,,,,why would you wantt o do that anyway? the e28 arm is sufficient anyway. It's the bushing that fails,not the arm.

[originalMJG]

ok then steve, i was asking that question myself, whether it would be an improvement. obviously not!

so from the information ive got so far, theres no need to swap suspension over, and the only improvement is the LCA from aluminium my question is answered then i think. and il just stick to the option of spax adjustable suspension for the e28.

thanks for the answers guys, youve put my inquisitive mind at ease

[papajetta]

the e34 front lower control arm should work. because the steel arm is the same number on both cars.
so is the stab links and tie rods,
i've done the research while looking for lemferder parts online.