E85 - Suspension Compatibility

A

ann.nonco

Member
Hi all,

I've been doing some research on the E85 platform and it seems the for the Z4 it shares many parts across the E36 and E46 timeline.
Just for the suspension, it seems that;
  • Front Suspension - Shocks E36 / Strut Perch (Hats) E46 / Lower Control Arm E46M /
  • Rear Suspension - E36/E46/E86 all cross compatible

Can anyone else chime in and double check if this is correct?
Any comments would be helpful for me and also anyone else planning to do the same.

E85 suspension parts are ridiculously overpriced sometimes when compared to an equivalent counterpart of a set but I guess that comes with the platform.

I don't plan to track the car etc so I don't mind the different valving and fluid rates - I hope to buy a E36 set of from shocks and replace the current ones that are specifically for the 2.2 model with M sport suspension (S704A Option) - which also seem to have a different part number versus the normal ones.

It's just a weekend car so I don't want to cash in large and get a full set of Bilstein's which in practice would be very nice to drive on otherwise.
 
I've always wondered where this comes from. From direct experience of having my 54 plate E46 320d[1] and 06 plate E85 2.5 parts in my hands, the springs, shocks and top mounts are completely different.

The springs are miles shorter (which necessitates different shocks by definition) so unless the overall strut length happens to come out the same I don't see how people come up with this. And, if they are a comparable length, then the spring rates will be totally different.

(Thinking about it, I'm pretty sure the overall strut length is different as I've had to adjust my strut compressor between uses going from one car to the other (with weeks between doing so, hence only being vaguely sure of myself.))

The E46 top mounts are slightly taller (say 10mm) but the camber pin is in a different place.

The control arm, bush and subframe at the front are all the same. At the rear the upper wishbone is shared with the E46, the lower one with the X3 while the trailing arms are unique.

Diffs and driveshafts are all E85 specific.


[1] The 320d and 325i use the same springs so I feel justified in comparing to the E85
 
smorris_12 said:
I've always wondered where this comes from. From direct experience of having my 54 plate E46 320d[1] and 06 plate E85 2.5 parts in my hands, the springs, shocks and top mounts are completely different.

The springs are miles shorter (which necessitates different shocks by definition) so unless the overall strut length happens to come out the same I don't see how people come up with this. And, if they are a comparable length, then the spring rates will be totally different.

(Thinking about it, I'm pretty sure the overall strut length is different as I've had to adjust my strut compressor between uses going from one car to the other (with weeks between doing so, hence only being vaguely sure of myself.))

The E46 top mounts are slightly taller (say 10mm) but the camber pin is in a different place.

The control arm, bush and subframe at the front are all the same. At the rear the upper wishbone is shared with the E46, the lower one with the X3 while the trailing arms are unique.

Diffs and driveshafts are all E85 specific.


[1] The 320d and 325i use the same springs so I feel justified in comparing to the E85
Click to expand...

Thank you for chiming in!

I've seen a few forums online stating that some parts were interchangeable - but after a bit more research you might be so correct as I could not find a single forum post seeing anyone complete a repair/build with a E36/E46 shock but several using E46 control arms.
If the E46 top hats are taller that would affect the camber for sure which isn't the best for the road so OE/OEM/DR it is.

Since the M springs lower the car even more it would be definitely safer to go with the OEM route.

Placing an order of some B4 Bilstein shocks now :thumbsup:
 
Just use RealOEM. It will tell you precisely which part numbers are shared across other bmw platforms;

https://www.realoem.com/bmw/enUS/select
 
Ed Doe said:
Just use RealOEM. It will tell you precisely which part numbers are shared across other bmw platforms;

https://www.realoem.com/bmw/enUS/select
Click to expand...

RealOEM is a godsend but the only problem with it is that sometimes for shared parts ex) 33526764000 - rear E85 shocks the E46 and E36 both all use the same part but it does not immediately show compatibility so a bit of context and inside knowledge is needed :(

Thank you for your advice though!
 
The E36 front struts have lower mounts which are the same as the Z4M (attached by two bolts on the side of the hub) but are completely different to the non-M E85/6, whose struts are lowered into the hub and secured with a pinch bolt.
 
plenty said:
The E36 front struts have lower mounts which are the same as the Z4M (attached by two bolts on the side of the hub) but are completely different to the non-M E85/6, whose struts are lowered into the hub and secured with a pinch bolt.
Click to expand...

Just as a matter of interest does anyone know if the E36 M3 front strut is compatible with the Z4M, better still if you’ve tried this configuration.

Reason I ask is I’ve got a set of new OEM Sachs E36 M3 front struts and will soon be looking to refresh my Z4M suspension so if anyone’s already done the hard yards or knows if do-able or not it would be much appreciated! 🙏
 
smorris_12 said:
I've always wondered where this comes from. From direct experience of having my 54 plate E46 320d[1] and 06 plate E85 2.5 parts in my hands, the springs, shocks and top mounts are completely different.

The springs are miles shorter (which necessitates different shocks by definition) so unless the overall strut length happens to come out the same I don't see how people come up with this. And, if they are a comparable length, then the spring rates will be totally different.

(Thinking about it, I'm pretty sure the overall strut length is different as I've had to adjust my strut compressor between uses going from one car to the other (with weeks between doing so, hence only being vaguely sure of myself.))

The E46 top mounts are slightly taller (say 10mm) but the camber pin is in a different place.

The control arm, bush and subframe at the front are all the same. At the rear the upper wishbone is shared with the E46, the lower one with the X3 while the trailing arms are unique.

Diffs and driveshafts are all E85 specific.


[1] The 320d and 325i use the same springs so I feel justified in comparing to the E85
Click to expand...

To SMorris_12's point on E46 front strut top mounts: I added E46 'rough road' strut tower reinforcing plates when I refreshed the suspension last Winter/Spring. I had to add new holes in the plates for the camber pins, else I would have had to remove pins from the strut mounts. Clearly the engineers reused many pieces, but they also changed up a lot of details - close, but not quite the same.
 
plenty said:
The E36 front struts have lower mounts which are the same as the Z4M (attached by two bolts on the side of the hub) but are completely different to the non-M E85/6, whose struts are lowered into the hub and secured with a pinch bolt.
Click to expand...

So I guess then for the E85/E86 base, E85/E86 Sport (M sport suspension (S704A Option)) share similar parts?
I've heard that the sway bar is a bit thicker and the springs are around 15mm shorter versus stock and shocks are valved differently due to the lower ride height for the S704A optioned cars.
Googling shows that many people fit the normal base model shocks on cars that have the S704A option and have it fine as the bolts line up just the valving isn't as perfect so ride can be a bit compromised.

The E85/E86M have a totally different setup which limits compatibility due to the vast difference in bolt positioning etc.
 
Sorry to resurrect this one but . . .

I have a 3.0 2003 E85 and it has the S704 M sport package on 17" wheels - its too low - comically so! Speed bumps result in horrendous scraping underneath, the slightest incline results in the front bumper scraping, I damn near ripped the bumper off going onto a gravel track today. Its become unbearable.

I dont care if its sporty suspension, I just want to be able to drive the car and at the moment, I'm driving in complete fear because of it!

Anyway . . . the question is, can I fit standard suspension? If so what do I do? Do I change the shocks and springs or just the springs?

Secondly - I've got both part numbers for the normal and S704 shocks from realoem, but when I put them into Bilstein it just comes back with B4's? So is B4 normal or S704 shocks?
 
You can raise it by just changing the springs, yes. But you'll almost certainly find that the shocks and struts are knackered when you strip it down. Msport shouldn't be that low though, only 15mm lower than standard, i have no issues with mine. Bilstien B4 are a popular swap.
 
Rockhopper said:
You can raise it by just changing the springs, yes. But you'll almost certainly find that the shocks and struts are knackered when you strip it down. Msport shouldn't be that low though, only 15mm lower than standard, i have no issues with mine. Bilstien B4 are a popular swap.
Click to expand...

Do you think getting new springs and shocks (M Sport) might make it slightly higher? Perhaps the current Sachs ones have 'degraded' over time?

I cannot fit standard springs as Bilstein don't do them for my Z4 - apparently as mine is an automatic - its heavier than manual transmission
 
Springs never really sag that much. My E85 sat low and would catch on every speed bump in christendom even with new springs. I made some spacers to sit on top of the strut in the tower to raise it 1/2" in the end. Later on I noticed I had standard springs on the back rather than sports ones which would have tilted the nose down slightly but, having swapped those too, it's not as if the nose is too high now.
 
Mine is also an auto. I had Suplex springs on the front, one broke so i fitted another pair of unknow make springs from eBay. 270mm long is the important info. The difference between auto and manual spec springs is negligible. Msport springs to seem to be quite hard to find at the moment, lots of online parts catalogues are incorrect, check for the 270mm length.
 
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