325i Sport suspension and bush confusion

[Chris_B86]

Hi Guys,

I have a 1990 325i Sport M-Tech 2, and it's just come off the road for winter to renew the tired suspension etc.

However, I'm getting confused looking at bush kits. Do I have eccentric or concentric bushes, and what size ARB's am I likely to have? I'm looking mostly at the Powerflex full kit.

Also what would people recommend suspension wise. I'm trying to keep the car fairly original, but the suspension is a bit tired now. Shortlist was the Billy/Eibach setup to stay in keeping with the car sitting on Billy's from the factory, and the H&R Cup Kit or Weitec Ultra GT.

I don't want to go silly low, or be rock hard, as it most likely won't see a track, and needs to cope with the great British potholes and speed bumps. I will be chopping and changing between the original 15" BBS's and 17" Alpina reps throughout the year.

Any help in this would be greatly appreciated as I'm trying to get all the parts together before it get's pulled apart as when I do get use of a unit, I'll be on a tight schedule to turn it around.

[Rtaylor2208]

Most people recommend going with OEM bushes as the chances are they will out live your car.

For the lollipop bushes go with Eccentric M3 bushes only available via BMW. Eibach B4 \ Boge Turbos OEM spec for the dampers I believe and pretty much everyone recommends the eibach pro springs or OEM Mtech springs if you are trying to keep the car looking fairly standard.

The H+R setup gets good reviews but I have heard a few unhappy comments from zoners on the weitec Ultra GT setup.

[Rtaylor2208]

Lots of information here in the zone wiki to get you started:

http://www.e30zone.net/e30zonewiki/index.php/Suspension

[Chris_B86]

Cheers for the quick reply.

So with regards to the bushes, would my car already be on eccentric, or can you fit either to the car. Obviously I will go for whichever is best, but just want to be sure there isn't one that won't fit

[Rtaylor2208]

from the wiki:

The lollipop bush is a strong circle of rubber, held in place with a circle of steel that directly bolts to the front chassis rail. The idea of the bush is to locate the wishbone to the car while allowing it to turn, based on the flexing of the rubber inside it.

The standard bush is a concentric design, meaning the hole for the wishbone is in the centre of the bush. M3 models were fitted with eccentric bushes, which pushed the end of the wishbone closer to the centre of the wheel arch, increasing the caster. This is considered a worthwhile upgrade for all E30s

[Chris_B86]

Cheers for that, Link is extremely helpful, particulairly with guide on rear subframe bushes

[polsta]

i may be wrong- but wouldnt you need a different set up of things for 15"bbs and 17" alpinas ? to keep swapping them over ? ie how awful wheel the 17" reps are and how they are not really any good with the rear camber ?

[Chris_B86]

The rolling circumference of the BBS's is actually slightly larger with 205/55/15's on compared to the reps with 205/40/17's on. To be honest the reps are only there to be used to preserve the BBS's, which will be on the car for shows etc

[polsta]

but the reps are a fair bit wider, when you have them on an e30, the rear innner edge of the tyres get eaten, and they ruin the drive i think anyway

[daimlerman]

Eccentric front bushes are a worthwhile upgrade,the solid rubber BMW one's I understand can be 'playful' to fit.I have used polybushes here,although they do transmit noise into the cabin.

Your ARB's could be one of several sizes,it's best to measure them before ordering your new bushes.
Two ways to measure;
1. Steal a tape measure from your wife/girlfriend/partner's sewing basket and measure the circumfurence of the bar and divide by 3.14(remember pi from maths at school?)
2.slide under the car with a selection of open-ended spanners and find one that just slides over the ARB.

[Chris_B86]

I think they're half an inch wider, tyre width is the same though. I haven't had any issues with scrubbing at the moment, but again that's one reason I don't particulairly want to lower it too much, as well as the fact my front bumper already takes a battering on the speed bumps near me. To be fair, I don't like the ride on the 17's, it's too bumpy with the lower profile tyres, and for some reason it follows grooves in the road really badly with them on. Majority of the time it will have the BBS's on, just depends what kind of show I go to

[Funnybear]

Rear tyre scrub on the 17's also depends on your car drop . . . Mine's been lowered by a previous council (going into the shop this week to get it all sorted) By dropping the car you change the camber from the suspension geometry. As you pull the bottom wishbone 'up' without changing the hub angle, so the car will naturally sit on the inside edge of the tyre. I've got 17 alp reps, and yes, they are hard, tramline like a mother 'fo'h, and I get through one set of rears a year. And thats not through thrashing, honest.

I didn't know they fuck up the drive though. How do they do that? Surely so long as they are both the same size wheels, all it will do is possible knock your speedo out a bit . . .

But anyway, I'm going to see about taking out some of the extreme lowering. Sick and tyred of scraping my baby over speed ramps and road cambers.

[polsta]

ruin the drive- just meaning make it not as nice or nimble feeling to drive, feels more a straight line car, they are bigger/wider, althogh i hadnt drive the same car on 17s then 15s- which would be the way to test and see the difference in the drive

my car had jamex lowing springs and 17 reps when i got it, horrible to drive really and 1 rear tyre had bad scrub on the inside when took them off and rest of the tyre looked like new

[Funnybear]

Ahhh. Gotchya. They give immense grip though, they just remove quite alot of the feeling when your on the edge. They go from grip to snap very very quickly. But boy, do they grip.