Z3M rear axle-how to recognise

[316i compact]

I located a ti converted to M3 ti (3.2 euro), and i wanna know how to recognise if the rear carrier, rear trailing arms, and rear diff are from the Z3 M. Is there an M badge on all of these components? Any par numbers on them? This is going to be really usefull for me, so i am aiting for your help. Any other suggestions on what to check on the car accepted!

[J!m]

The brake calipers have the M on them (if they remain from the M Roadster donor car). None of the other components have a blatant M designation. The half-shafts and CV joints are easily recognizable as much larger than the ti parts. Same with the trailing arms and sub frame member (both beefier than the ti parts). The M diff also has the large finned cover which does not fit the smaller case of the ti diff, so that's hard to fake.

If you are not one with a trained eye, a side-by-side comparison with a stock ti will make it clear if these have been changed or not.

The problem comes into play when people try (and some succeed) mixing and matching parts (AKA kit bashing) to save a few bucks. Then you may have a good diff for example, but the half shafts are weak, or the CVs are weak, or the bearings are under size for the side load, or the trailing arms are weak, or the sub frame is weak, and on and on... If you reinforce one part to prevent failure, the 'weak link' is relocated to another part, which may not be as easy to replace. A case in point would be the Land Rover half shafts (inside the axle tube in that case) which break quite often in old Series trucks. These are often replaced with stronger units, which seems like a good idea. However after the axle swap, they start to complain of frequent u-joint failure and ring and spider gear failures in the diff. So, the axle problem is solved, and another problem is created. This is the main reason why I so strongly suggest replacing the entire unit, rather than piecing it together from many BMW parts (plus its way less labor this way, and my time has value). You just are not capable of accounting for all the variables that are accounted for when these drive SYSTEMS are engineered at the factroy...

[mohaughn]

Here is a side by side comparison of the m-coupe and regular trailing arm for our cars.

http://e30m3performance.com/now_show...arms/index.htm

It is pretty easy to see the extra reinforcement on the arm.