What to do suspension wise?

[junglist]

Back in June I found I had the old snapped spring issue, so I replaced the whole lot with a set of Eibach Pro springs.

I'm really pleased with how they look, especially combined with the 20mm spacers on the rear.

It's fine around town however when on a spirited drive on country lanes / bumpy roads, the car keeps bottoming out. I took it up to the Highlands a few weeks ago and found myself having to drive at 5/10, the noise from hitting sharp bumps is awful! The same trip a couple of months earlier on the standard suspension provided no problems whatsoever.

I thought it was the spacers at first (slight markings to the outer rim of the tyre) but from recent driving it seems as if it's more than that - sounds a lot more "bang" like rather than the grazing noise from the tyres catching if you get me.

Bushes, droplinks etc have all been renewed and it's recently had a full Hunter alignment so there's nothing wrong there.

So where do I go from here?

• Have the arches rolled to see if this gets rid of the issues (probably not)
• New set of OEM dampers and springs (would lose the improved look, and it'd only be a matter of time before a spring snapped)
• Replacing the OEM dampers with some uprated ones, eg Bilstein B8 (not guaranteed to solve the problem so could be potentially be a waste of money)
• Coilovers - this seems like the best option as I could match the current height of the Eibachs but have firmer damping so no bottoming out? I wouldn't want a harder ride though if I could get away with it

I'm not interested in super lowz - I just want to be able to drive our roads at a decent pace without worrying I'm smashing my car to bits or having my teeth rattled out!

Budget would probably be around £800.

I know there's lots of people running coilovers on here, would appreciate some opinions / advice. Thanks chaps.

 

[Stratts]

I know this is a few weeks old, but hope to help.

When you fitted the springs did you shorten the bump stops? The bottoming out can be helped by cutting the bump stops or fitting the specific BMW M Sport ones, giving the suspension more travel.

That's why there are M Sport ones in the first place, but cutting them yourselves is an option. Obviously if you wanted to do it now you would need to have the springs off again to get to the bump stops.

 

[mr wilks]

Ive had a fair variety of BMW 's ( 3, 5, 6, Z & X ) & whilst i like the looks of the Sport spec i realised that SE cars ride so much better .
SE spec cars can be bought for much less than equivalent sport spec then upsize the alloys & tyres to close the arch gap whilst still having a compliant ride to thrash around the lanes at reasonable speed without wincing everytime you bottom out + long motorway runs are supremely comfortable as opposed to clattering your gnashers
Its a learning curve & part of the enjoyment is the exploration ,
hope you work yours out

 

[jan_tekin]

I had the same problems hen I was running H&R lowing springs. Looked great but hated the ride. Even my misses said I ruined the car lol
Maybe with new shocks it might have improved, but most standard shocks don't really take being lowered. B8's are an option but then your not fair of the cost of a set of coilovers which give you the added option of adjustability.

I'm running a set of 224s which used to scrub a lot on the front and a little on the rear when I had my car on H&Rs(also had a slight mark on the rear tyres). Now I'm running my KW V2 I've been able to add a spacer to the front. I'm running it a little higher in height more near eibachs but without the crashy ride and bottoming out it can handle more then I dare to through at it now

 

[junglist]

Thanks for the replies guys.

When you fitted the springs did you shorten the bump stops? The bottoming out can be helped by cutting the bump stops or fitting the specific BMW M Sport ones, giving the suspension more travel.

With it being a sport spec originally, it should have these fitted?

B8's are an option but then your not fair of the cost of a set of coilovers which give you the added option of adjustability.

Yeah that's what I'm thinking. A set of B8s work out at around £600 and I'd still have no adjustability.

I'm running a set of 224s which used to scrub a lot on the front and a little on the rear when I had my car on H&Rs(also had a slight mark on the rear tyres). Now I'm running my KW V2 I've been able to add a spacer to the front. I'm running it a little higher in height more near eibachs but without the crashy ride and bottoming out it can handle more then I dare to through at it now

How come the scrubbing has now gone even though the width is still the same (even wider on the front now with spacers), is it simply a case of better damping with coilovers? How do you find the ride with the KW V2s to OEM springs and dampers?

I do think coilovers are the way forward but can't afford the £1300+ for KW V2's. I was wondering how the likes of the D2 / Spax etc compare with them.

Ideally someone would lend me their car on coilovers for a day so I can really test it out and confirm the spec I need but I know that's never going to happen lol.

 

[Stratts]

Thanks for the replies guys.

When you fitted the springs did you shorten the bump stops? The bottoming out can be helped by cutting the bump stops or fitting the specific BMW M Sport ones, giving the suspension more travel.

Possibly (and I realised this straight after I posted), but you've lowered it even more then the M-Sport spec so you would need to cut them down even further than the M ones.

The choice of shock absorbers can make a difference as well of course. Just an idea.

 

[swanicyouth]

This is my opinion - but unless your racing the car - stick with stock springs. The aftermarket drop looks good, but doesn't have the engineering to it the BMW springs will have.

People love to think they can re-engineer their own cars better than the engineers at the factory. Lowering cars is tricky, and can affect a lot more than ride height. Cutting bump stops or buying M bump stops is just compensating for the car bottoming out.

 

[Yorkie Z]

This is my opinion - but unless your racing the car - stick with stock springs. The aftermarket drop looks good, but doesn't have the engineering to it the BMW springs will have.

People love to think they can re-engineer their own cars better than the engineers at the factory. Lowering cars is tricky, and can affect a lot more than ride height. Cutting bump stops or buying M bump stops is just compensating for the car bottoming out.

Problem is is that bmw engineered there springs so well that they snap.!!!!!

 

[TheHoff]

This is my opinion - but unless your racing the car - stick with stock springs. The aftermarket drop looks good, but doesn't have the engineering to it the BMW springs will have.

People love to think they can re-engineer their own cars better than the engineers at the factory. Lowering cars is tricky, and can affect a lot more than ride height. Cutting bump stops or buying M bump stops is just compensating for the car bottoming out.

BMW mass produced the Z4, and therefore mass designed it too; anyone who is intelligent or suitably experienced can adapt their Z4 to suit their needs. As an Engineer (a proper Engineer, not a Gas or Telecomms Technician) with hands on experience, I feel more than qualified to do this. Lowering to obtain a certain look is one of my pet hates however - especially Hella-Gash.

Provided the rest of the setup is appropriate for the intended use, and is safe, then cutting bump stops can be entirely acceptable too.

 

[jan_tekin]

How come the scrubbing has now gone even though the width is still the same (even wider on the front now with spacers), is it simply a case of better damping with coilovers? How do you find the ride with the KW V2s to OEM springs and dampers?

I do think coilovers are the way forward but can't afford the £1300+ for KW V2's. I was wondering how the likes of the D2 / Spax etc compare with them.

Ideally someone would lend me their car on coilovers for a day so I can really test it out and confirm the spec I need but I know that's never going to happen lol.

Yes, I have them set not fair of there recommended settings but if i was to make them softer the scrubbing comes back. The ride is pretty firm now but I've change pretty much everything up front.

Its hard to compare it to stock as my car was on 80K when i fitted them and both rear shocks where dead and one of the fronts had blow its seals so I only had one half decent shock Pritty sure lowing my car finished everything off

 

[mad4slalom]

This is my opinion - but unless your racing the car - stick with stock springs. The aftermarket drop looks good, but doesn't have the engineering to it the BMW springs will have.

People love to think they can re-engineer their own cars better than the engineers at the factory. Lowering cars is tricky, and can affect a lot more than ride height. Cutting bump stops or buying M bump stops is just compensating for the car bottoming out.

Problem is is that bmw engineered there springs so well that they snap.!!!!!

touche' !