Rear M3 subframe

LittleZ4

Active member
Afternoon/evening all,

I'm hoping this will be a really quick question. Having had a look through some posts on various forums (clearly this forum is the best :D ) it looks like an M3 rear subframe with all its goodies will bolt into a non M Z4. Cooling fins trimmed of course.
In order to make this work with the 6 speed box, a z4m prop is required?.......... At least this is what I have read.
Now would a a z4m and an E46 M3 prop shaft be the same? Or would I be right in thinking the M3 prop is a little longer.

Also would the brake bias be out with the larger rear brakes?

Any info or a link to a post would be amazing. I will of course continue trawling through as many posts as I can that have M3, diff, subframe.........there are many!! :?
 
You need a custom made shaft in order to mount the subframe with its diff. As for the brake bias I wouldn't be that worried, maybe if necessary you can compensate the bigger rear rotors with some better braking pads on the front.
 
Thanks for the reply Sloan - so do you think that the M3 prop would be ok to modify. Both the ends look like they would fit/bolt up......
 
I am not an M3 expert, but am I right in thinking e46 M3 subframes have a tendency to crack ?
 
Bing said:
I am not an M3 expert, but am I right in thinking e46 M3 subframes have a tendency to crack ?
Isn't it the floor where it attaches that cracks, not the actual sub-frame? Never heard of this issue on Z4s.

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mmm-five said:
Bing said:
I am not an M3 expert, but am I right in thinking e46 M3 subframes have a tendency to crack ?
Isn't it the floor where it attaches that cracks, not the actual sub-frame? Never heard of this issue on Z4s.

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Actually yeah, you are correct. My apologies.
 
Christ those pictures don't paint a pretty image!!

I've heard that strut towers can mushroom and crack hence the reinforcement plates (which I already have in place)

So by the sounds of it, an M3 rear subframe and modified prop should bolt in.

I've already got 325mm discs up front so that should lessen the brake bias a little?
 
LittleZ4 said:
Thanks for the reply Sloan - so do you think that the M3 prop would be ok to modify. Both the ends look like they would fit/bolt up......

I've got no idea, I think you are correct, but don't know for sure. Maybe it's better to ask the shop that's going to adapt the shaft for you what they think?
Also, bimmercat.com it's a great place to find the lengths of different shafts, you'll see differences between engines and types of transmission.
If you end up doing it, let us know.
 
I've looked on real OEM and there are differences between the M3, z4m and Z4 shafts. The normal Z4 is out of contention as the diff end is incompatible, so that leaves the others. Z4m prop seems to be as rare as rocking horse sh!t so that kinda leaves an M3 one.
This all started as needing to replace parts to be able to sort out the tracking......might have escalated quite quickly!!
 
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