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Just wanted to get some clarification from those in the know, I know some items are interchangeable from Z4M and M3, I believe the ARBs, strut brace with a bit of modding, and possibly suspension components, what about wishbones, drop links etc? Clutch?
Help much appreciated as theres always an abundance of performance or brand new oe parts for sale for the E46 M3 but much more scarce for our Z4Ms
TIA.

Grab yourself the last 7 digits of a vin number for an E46 m3 and a Z4M, and get yourself onto RealOEM.com

I can confirm the rear ARB is the same as I have an Eibach M3 rear fitted to mine. Front and rear AP calipers are the same, although the fronts require a 2mm spacer on both the caliper mounting and the disc bell or 2mm caliper spacer and Z4M specific bell.

Fishy Dave wrote: ↑Wed Nov 22, 2017 3:51 pm I can confirm the rear ARB is the same as I have an Eibach M3 rear fitted to mine. Front and rear AP calipers are the same, although the fronts require a 2mm spacer on both the caliper mounting and the disc bell or 2mm caliper spacer and Z4M specific bell.

I have heard that the rear ARB on the Z4M Roadster is 21.5mm, opposed to 22mm of the Coupe And E46 M3. is this true?

Answering my own question, it is indeed true that the M Roadsters have a 21.5mm dia ARB, opposed to 22.5 on the Coupe and M3. Just checked it on real oem.

Gustavo7 wrote: ↑Wed Nov 22, 2017 4:57 pm Answering my own question, it is indeed true that the M Roadsters have a 21.5mm dia ARB, opposed to 22.5 on the Coupe and M3. Just checked it on real oem.

Yes, i should have been clearer, when I said 'they are the same' I meant that they are interchangeable.

Front brake calipers are the same. Carriers are different. Rear calipers fit but have smaller pistons. Rear discs are the same. E46 CSL has the same brakes, front and back. Strut braces are the same. Engine is basically the same but the ECUs are different (ours is an update of the M3 unit).

MrPT wrote: ↑Wed Nov 22, 2017 10:57 pm Rear discs are the same.

That's a relief as just bought some at a decent price to put into stock for change next year, and new pads all round as the standard BMW material was lacking on my recent Welsh trip.

I know about the CSL bits, I've heard they share the steering rack too? Not sure if that's true or not.
Apparently it's a revised S54 with an ecu that's 3x faster at processing data (60m processes a second as opposed to 20m), not as easy to add maps and mess about with as the E46s though, my mate has a supercharged m3 and he's always getting his tuner to send new maps, where I've been told he needs the car physically there to do anything to mine.
I have an M3 Strut brace but it had to be modified to fit, they're similar but not exactly the same. Although I love the uniqueness of the Z4M, I do wish more was interchangeable as there's so many new and used M3 performance/uprated parts out there for sale on forums and websites, and due to the abundance they're always quite low in price compared to Z4M specific stuff such as exhaust components, aero parts etc.
Oh well, the price we pay for such a rare and special car in today's performance car market where there's 20k plus examples worldwide of everything!

I fitted an M3 strut brace (OE BMW) without requiring any mods.

Its not so clear cut on the steering racks as the Coupe and Roadster have different racks - Coupe is a quicker rack . Never really understood why?

Justino wrote: ↑Fri Nov 24, 2017 9:07 pm I fitted an M3 strut brace (OE BMW) without requiring any mods.

Its not so clear cut on the steering racks as the Coupe and Roadster have different racks - Coupe is a quicker rack . Never really understood why?

What did you do about the locating pins sticking up through the strut tower?

Cant recall now, pretty sure I didn't remove them, will take a look tomorrow.

steering rack on the z4mr/c is quicker than all the m3 models including the csl, coupe has the quicker rack than the roadster....

The whole rear end seems to be the same.

clutch has a different spline count in the middle so cant be used.

ABS / DsC is all from the CS/CSL

Ecu is an iteration of that used on the v8 / 10 unit.

s54 seems largely unchanged

Beedub wrote: ↑Sat Nov 25, 2017 3:29 pm The whole rear end seems to be the same.

Well yes apart from the springs/dampers/arbs being different size/settings and the diff being different yes I guess you could say that.

Beedub wrote: ↑Sat Nov 25, 2017 3:29 pm ABS / DsC is all from the CS/CSL

That's not true, it's similar to one from an e90, DSC MK60E5
That's why we have all that brake assist nonsense that the csl doesn't have, that uses MK60

Beedub wrote: ↑Sat Nov 25, 2017 3:29 pm s54 seems largely unchanged

Yes, though afaik the sump is slightly different, and obviously headers and exhaust are different.