Help with new suspension parts please

[Pond]

The car is a 2001 (built late 2000) 3 litre Z3. I think it is a 'sport' spec if that makes any difference.
I need to replace my springs for lowering ones and as all of the rubber suspension parts have either perished or been eaten (yes eaten....by mice) I am going to replace the dampers, bump stops, etc while doing the springs.

I need to lower my car as far as is reasonably possible but need some suggestions as to which suspension parts to buy. I was going to order some OEM-type dampers and a set of Eibach pro lowering springs, but is there anything better for the Z3? I don't need the cutting edge in handling, but would like quality parts and I need it lowering as far as possible.

Also I am unsure which rubber parts I need. I briefly looked on realoem but I am still unsure. There are a pair of rubber 'bushes' on the lower suspension arms (just in front of the rear wheels) which I have been told by @Mint need replacing but don't know what they are called.

I can't post pictures of the areas on the car as I haven't got the car with me at present.

My go-to parts place is Autodoc BTW, unless anywhere is better (cheaper) for Z3 parts.

Any help would be much appreciated.

 

[Pond]

I have found a couple of pictures which may help:
The picture of the front nearside wheel just shows the top 'bump stop which has been nibbled to nothing.
The picture of the rear nearside just shows the 'bush' I mentioned, just poking out next to the end of the sill.

 

[Scooblitz]

If looking to go really low, coilovers or even airbag suspension is out there.

Coilovers - Depends on the budget - £500-£1300 but will suggest that only the fronts will have coilovers, the rear will only have springs and a height adjustable adapter.

Vogtland, AP racing, HSD, H&R and KW are a few to look at. The AP racing look decent and actually work out less than a fixed shock and spring set up using Bilstein and Eibach pro springs.

 

[Scooblitz]

BC Racing too. How could i forget.

Widely used and a firm favourite. Probably the upper mid cost coilovers.

As is often the case, you get what you pay for. Avoid the cheapies

 

[Eddie Zedder]

BMW part numbers -
33311090946 for the beam bushes.
33329061945 for a set of trailing arm bushes.
33171090950 for the diff bush.
You will probably need ARB bushes (and drop links) as well but ideally you need to know the size of as these vary in diameter depending on model. The size is usually stamped on the clamping plate.
Or you could go down the route of a poly bush kit which are easier to fit like these from Powerflex

Powerflex - Performance Polyurethane Bushes

www.powerflex.co.uk

 

[Jam03]

I have found a couple of pictures which may help:
The picture of the front nearside wheel just shows the top 'bump stop which has been nibbled to nothing.
The picture of the rear nearside just shows the 'bush' I mentioned, just poking out next to the end of the sill.
View attachment 335735View attachment 335737

The bush next to the sill at the back is the beam bush. One on each side. Many threads on here about them.

 

[Mint]

Yes as @Jam03 says, the rear beam bush is the one I mentioned to you. There should be a gap (5mm or so) between the beam and the supporting plate.

 

[Duncodin]

Beam bushes. Did mine a while ago. There's a few posts on the forum how to do them without taking out the whole beam. That's the method I used.
Can't say I noticed any difference in performance but going over pot holes always used to be thump at the back and a weird feeling. That was the beam bouncing on the base plate (push rod they call it). New bushes fixed that.

I also did Coilovers. Although the reason I did them was not to lower the car (much) but to get rid of the big Spring plate base plate on the strut that sticks out over the tyre. I want to use taller wheels/tyres and they'd foul on the original spring plate.

I wasn't sure they would do what I wanted so just bought cheap ones. The idea being that I'd invest in decent ones further down the line if the theory worked out for me.

Anyway. 220 quid for the set from ProSport They're the LZT line for E36 Compact. Spoke to the supplier who didn't list any for Z3 and he explained (he claimed) that nobody actually makes them for Z3. They make them (he said) only for E36 Compact and they are the ones to use. But, he said, the Z3 is lighter at the rear so won't go as low. So that's what I've got. Currently the fronts are as high as they'll possibly go and the rears are as low as they'll go. (The man did say rear wouldn't go as low because the Z3 is lighter at the rear)

Height, for me, is a little too low but that will change once I get my taller tyres on.

I don't drive fast round corners and don't do track days or anything like that and, I must say, I'm quite pleased with these cheapo springs. Pot holes and road humps are actually quite comfortable so not too hard.

 

[Pond]

I have found the BMW part numbers for most of what I need, thanks, but realoem seems to deny that my Z3 has springs! I would like the part numbers just to cross reference against new ones.

 

[Pond]

So I have done a little research and think that either the Bilstein B12 kit (with eibach springs) or Spax PSX adjustable damper kit with lowering springs could be my best bet. They are both very similar cost, around £800 for all four dampers and springs.

I presume I will still need OEM bump stops?

 

[Zephyr]

Putting B12s on a car that is bolted together is not a good idea unless you did a hell of a job and you have reinforced all the conmection points with shims and rubber.
About 80% of your shell is fiberglass, be very carefull on what you do.
You can lower it without making it so hard.

 

[Duncodin]

Putting B12s on a car that is bolted together is not a good idea unless you did a hell of a job and you have reinforced all the conmection points with shims and rubber.
About 80% of your shell is fiberglass, be very carefull on what you do.
You can lower it without making it so hard.

@Zephyr Bear in mind that the rebody process does not remove or replace anything structural. The flexibility of the car isn't changed in any way. The original z3 steel monocoque is still intact.

But I do agree that if grp panels are just 'resting' loosely on the frame then a hard ride will have them flapping about. But then the same could be said for any bolt on parts on any car such as spoilers, wheel arches, body kits etc if not fitted securely

 

[Zephyr]

@Zephyr Bear in mind that the rebody process does not remove or replace anything structural. The flexibility of the car isn't changed in any way. The original z3 steel monocoque is still intact.

But I do agree that if grp panels are just 'resting' loosely on the frame then a hard ride will have them flapping about. But then the same could be said for any bolt on parts on any car such as spoilers, wheel arches, body kits etc if not fitted securely

i have zero experience from the shells you are using and probably they are of good quality and solid.
But from what I see in Beach Buggies that are a one piece tub bolted on a Beetle chassis (not the most rigid and not by far the most ideal one for putting fibreglass and metal together - with their different stress tolerance) cracking in contact areas is pretty common.
That is why everyone I know with a kit has reinforced all the contact and bolt points with metal plates and has put elastic flanges between them.
As for the hard suspension, this is something I asked in my thread, since every one of these VW kits makes a “dustbin thud” every time the car hits a pothole or a bump.
But again, apples with oranges, one solid piece vs four or more parts on your case.
Not insisting on anything here, just giving a heads up just in case

 

[Pond]

Putting B12s on a car that is bolted together

My body is bonded on with flexible adhesive everywhere it is fixed to the chassis.
DNA thought about the lack of flexibility in GRP when designing their bodywork, so nothing metal touches anything GRP, or it would craze/crack over time.
The suspension points/ structure of the car haven't changed. I really don't think putting slightly stiffer dampers on will make any detrimental difference.
The original Z3 body panels were all bolted together!

 

[Pond]

As for the hard suspension,

I am not looking for hard suspension. I just need to lower the car so the dampers might as well be changed while I am in there, along with some of the rubbers.

 

[Pingu]

I had to use BC coilovers as nothing else would lower the car enough. They come with adjustable dampers which can be set quite soft, or rock hard. You can also get adjustable camber plates, or adjustable camber and caster plates for the front.

 

[Duncodin]

. . .
. . . from what I see in Beach Buggies that are a one piece tub bolted on a Beetle chassis . .
. . .

Beetle isn't really a chassis. It's just a flat floor panel. Think of it like a sub frame that needs a body for strength.

Having said that I'm sure that when BMW were doing final roadworthyness crash tests smashing z3s into walls the crash test dummies were in cars that had bonnets, bumpers and wings etc. Which, even though bolted on, still play a role in the safety of the car as a whole. So, personally, I think we're in a kind of grey area when we rebody'ers say our franken zeds are as safe as an unmolested zed.

 

[Zephyr]

Beetle isn't really a chassis. It's just a flat floor panel. Think of it like a sub frame that needs a body for strength.

Having said that I'm sure that when BMW were doing final roadworthyness crash tests smashing z3s into walls the crash test dummies were in cars that had bonnets, bumpers and wings etc. Which, even though bolted on, still play a role in the safety of the car as a whole. So, personally, I think we're in a kind of grey area when we rebody'ers say our franken zeds are as safe as an unmolested zed.

We will die like real men.

 

[Pond]

So, personally, I think we're in a kind of grey area when we rebody'ers say our franken zeds are as safe as an unmolested zed.

When you take the roll hoops, airbags and headrests out they are definitely less safe. But then the whole point is to re-create something from another era when none of the safety stuff was invented IMO. At least we still have ABS, power brakes, DSC, etc.

If I were looking to buy a multi-million pound classic car from the 1960s I wouldn't turn it down cos it didn't have airbags.

 

[Pond]

I had to use BC coilovers as nothing else would lower the car enough. They come with adjustable dampers which can be set quite soft, or rock hard. You can also get adjustable camber plates, or adjustable camber and caster plates for the front.

Was fitting coilovers on the rear a PITA, or is it fairly straight forward?