Rear Shock Mount Z4 Coupe vs Z4 M Coupe

[rocky79]

Hello all,

I am having a bit of dilemma, I ordered the OEM Rear Shock Mout from ECS tuning part#33506777037 for the Z4 Coupe
It turns out that this part has a long lead time and sent me an alternate part which is 33526779670 which I found out that it is listed as a replacement RSM for Z4Mcoupe and all E46s.
Real Oem only list one part# for the Z4 coupe without any cross reference.

My question is are the Rear Shock Mounts for Z4 Coupe and Z4 M Coupe different of the same?

I appreciate the feedback.
Z4M RSM that I just got by mail.

[Finnegan]

Appears it's the same part. Click on the image if using mobile to see the whole screenshot. I used the part number search on Realoem to generate an xref using your part number.

[The HACK]

Actually the 3.0Si Coupe and the rest of the Z4s do not share the same shock mount PN. Weird.

[rocky79]

Originally Posted by Finnegan

Appears it's the same part. Click on the image if using mobile to see the whole screenshot. I used the part number on Realoem to generate an xref using your part number.

I saw and the 3.0Si E86 is not listed as a cross refrence. Only the M coupe is.
Did BMW make a RSM that only fits the Z4 3.0SI coupe?

[The HACK]

The only way to know, IMO, is to remove your shocks and try and install it. Because the PN is different, they (BMW) definitely made a RSM just for the 3.0Si Coupe. But it doesn't mean the MZ4 Coupe RSM won't fit.

For example, I put that same PN for the MZ4 Coupe in my E30 318is when I bought the car. PN for the E30 318is is different, but the RSM for the MZ4 Coupe fits it just fine. Even my E46, it had a different PN as the PN for the E46 M3 convertible, but the same RSM fits in the E46, despite those cars sharing the same assembly line.

What we can't tell is, are the PNs different because BMW used a different rubber material in the shock mount, or did they actually alter/change the shock mount design just for the 3.0Si Coupe? I think it's far more likely that it's just a simple rubber material change to soften the shock mount to make the ride more compliant for the 3.0Si Coupe, which would require a new PN but not a different design. And since they likely sourced the part from a tier 1 or tier 2 supplier, the cost to them to put in a new rubber material is the same.

[Finnegan]

Haven't looked but are there separate products for Rogue RSMs? If the 3.0 and ///M share the same part for those, then difference may be exactly as The Hack notes. (Another way to check perhaps?)

[rocky79]

The Hack that's a good point. I was thinking a different RSM dimensions but it could well be a different rubber material.

if anything I am assuming the Z4M RSM should be stiffer?

Finnegan, you also have a point. Rogue RSMs are the same desgin for all E46 and Z4 models. That's a clear indication that the bolt pattern as well as the size should be the same.