Higher or Lower ? M30B35 Touring suspension help . . .

[fastdiablo]

So here's the dilema, I've just bought a new barge



Its got an m30b35 lump thats had some major work and is now putting out some monster horses. It has all the power it needs but handles like a 3 legged donkey ! . . . Its lowered 60mm I think, has Spax shocks and is running on 205/45/16 tyres.

The first prob is some serious vibration coming from the n/s front at about 90mph. Im thinking this could be wishbone rear bush. IF this is correct am I best replacing the wishbone complete with ball joints and rear bush, is it worth putting on M3 eccentric ones ? . ..

Prob 2. The Spax shocks and unknown springs, these seem to be very stiff with little travel and dont seem to be able to absorb some of the craters Highways agency allow on our roads. Should I change the springs to 30 mm or even go back to std height.

What are my best options to give a comfy ride AND be able to handle the extra weight and power of the boat anchor ?

Prob 3. As said, it has some nice low profile tyres, 205/45/16, would I be better putting on a 55 profile to help it handle better ?

Prob 4. Exhaust is REALLY LOUD ! and is causing some clearace issues (another reason for thinking about raising he suspension) . . . Its a Scorpian M3 system. The back box is a large cylinder with twin exit pipes. This cylinder is too long to fit in the recess for the std back box, would I be able to fit a std 535 back box in that space ? . . .

Any help welcome

[bene30jane]

is that the car from ebay?.... looks cool!!.... i,d check the lower arm rear bushes for wear and also check the condition of the shocks and top mounts.... the springs are probably stiffer due to the extra weight up front.... some one here would be able to lead you in the right direction of springs with a simalar conversion.....

[fastdiablo]

Yeah . . . Thats the one . . .

Lower arm bushes were my first thoughts too . . .

[Morat]

bearing in mind that I've no experience with this sort of problem, I'd be inclined to check out all the bushes/topmounts etc first and see what is broken. They'll need fixing anyway so you may as well do it before you splash out any cash on changing things around.

From there, if you are staying low then eccentric wishbone bushes are the way to go but ride height (imo) will depend very much on how you intend to use the car.

[fastdiablo]

Not really had any thoughts on top mount bushes . . . If they are shot what would I feel ? . . .

The car is going to be my daily smoke with loads of different duties so ride height will be dictated by best set up for best handling . . .

[Brianmoooore]

Problem 1: Could well be the front arm bushes, but equally could be worn joints on any of the front suspension components.
Genuine E30 M3 eccentrics are worth fitting in any case with this kind of spec, but don't forget to retrack afterwards.
Problem 2: Spax and comfort/handling don't belong in the same sentence!
Go for Eibach/H&R springs on about a 35-40mm drop, with Bilstein dampers. Expensive, I know, but you get what you pay for!
This system won't be too different from the M-tech set up - BMW knew what they were doing!
Problem 3: 15's would probably be marginally better than the 16's if other things are equal, but there won't be much in it.
Stick with what you have until the suspension is sorted.

[fastdiablo]

Thanks Brian, looks like its hand in pocket time again ! . . .

[fastdiablo]

I have a call out for the guys at Evolve to call me about shocks and springs,

What sort of costs are involved with doing,

M3 wishbone bushes,

Is it worth getting new wishbones with ball joints or just replacing ball joints

Top mount bushes/bearings, is it worth putting on adjustable camber plates ,

Anything I have missed ? ? ? . . .

[Brianmoooore]

M3 wishbone bushes were around £20 the pair from BMW the last time I bought some.
Whether or not you need new wishbones depends entirely what condition they are in! I've found that a little new grease doesn't go amiss, occasionally.
I'd fit adjustable toe/camber plates to the rear a long time before I'd fit them to the front. E30 front suspension seems to stay in spec. much better than the rear.

[fastdiablo]

Thanks, will report back when sorted, maybee a few weeks to get it together though . . .

[Jhonno]

Andy's old Touring..

[fastdiablo]

You know this car ? . . . Its a fantastic build with huge power and great brakes !

How did he get on with the handling ? . . .

When did he sell it ? . . .

[Andy335Touring]

G*** WOO ??

It was sold sept/oct last year. I was in fear of being made redundant so the car had to be sold.

The Spax were never briliant handling but were OK, a bit too hard for the road. I fitted the brakes and the wheels at the same time, this increase in unsprung weight didn't help the handling.

With a better spring and damper combo this might help, also if you could get some different lighter wheels that fit over the brakes will help too. Not 100% sure but 16" Hartge's might fit over the brakes and should(??) be lighter.

To help you problem solve it has had...........

New M3 ecentric front TCA bushe's and TCA's 3-4 years ago
New subframe bushes with some plastic void bush fillers 3apx years ago
New trailing arm bushes less than 1 year ago
NEW rear shock top mounts 3-4 years ago
New rear ARB bushes(never got around to doing the fronts)
New ARB drop links all round i think ? 3-2 years ago

It's on the original ARB's.

Drop me a PM if you need any more info, just bare in mind i'm not on here that often any more.

[fastdiablo]

Hi Andy,

Thanks for getting in touch, it must be wierd seeing your old car on here in the hands of a stranger

I'm hoping to get the handling sorted. Aswell as the prob with the Spax shocks it has some strong vbration coming frm the front n/s corner at 90mph which you cant seem to drive through, it just gets worse, it feels more like a bush problem than a shock failure . . .

I've been onto the guys at Evolve and have ordered a set of Bistein B8's and Apex springs with a 30mm drop. While its in the air and the spanners are out i'm going to put on new M3 TCS bushes, front and rear top mount bushes and an E36 steering rack . . . Hopefully it will get things more under control


When all this is done I will see how it goes and may put a set of tyres on with a 55 instead of 45 profile to try to help it more . . . if nothing else it will help it climb over some of the speed "mountains" in the roads round here

Will keep you updated

Ian . . .