Sub-frame reinforcement plate upgrade for Non-M

Originally Posted by Grande D

Is the M3 plate made out of steel?

no it is made of 3mm thick aluminum. it's benefits were the weight and the new mounting points on the contol arm bushings to tie them together. the NACA air intake that direct cool air to the transmission is another benefit.

the way this mounts which is integrated to the control arm bushings, and being aluminum, makes me wonder if it's really a good idea to switch over? without those mounting points it's likely to be less firm in it's overall design than the standard steel non-M plate.

Originally Posted by Alex323Ci

no it is made of 3mm thick aluminum. it's benefits were the weight and the new mounting points on the contol arm bushings to tie them together. the NACA air intake that direct cool air to the transmission is another benefit.

the way this mounts which is integrated to the control arm bushings, and being aluminum, makes me wonder if it's really a good idea to switch over? without those mounting points it's likely to be less firm in it's overall design than the standard steel non-M plate.

SS already confirmed that this plate is used on the Z4M. The Z4M uses ZHP control arms. So it's use in the same manner as we would use on our non-Ms if we swapped. The biggest problem looks to be oil changes.

The non-M plate on later E46s is aluminum too, I'm 99% sure.

Originally Posted by Mango

I think you're assuming that every change from the E46 to Z4M has to=improved steering feel. The chassis of the E85 coupe is a hell of a lot more rigid torsionally than the E46 coupe so that right there should increase handling/steering feel alone. The car is also lighter and lower.

Still not convinced that road feel or steering feed back has anything to do with the way the strut attaches. The strut simply rotates on top through a bearing and is the backbone of the mcpherson strut system. If you mean more vibration, then maybe i could understand since there's more of the strut body screwed/attached to the spindle?

Is there any documentation on this from BMW in the way of technical literature or otherwise? Of course I could be wrong, but just not seeing it how the strut attachment at the bottom alone corresponds to steering feel. If we use that logic, then I would think the 1M would have poorer feel than a Z4M or E36 M

More steering feedback at least. I suppose that could be translated as vibrations -- but I kinda like feeling the road through my steering. Also seems like that mounting style may lower Cg

In any case, e36 is less stiff than e46. And I'm not convinced that the E46 M3 coupe is that much less stiff than the Z4MC -- there's a lot more bracing than a non-M, and even the E30 M3 is apparently 22500 NM/° -- e46 should be more. So it's not quite 34,000, but I bet it's still in the mid to upper 20s. I don't believe the numbers floating on the Internet for a second since they've never been published. Only published values are from the e46 convertible, which are higher than the frequently quoted numbers.

And the 1M very well might have poorer steering feel. Most newer BMWs have stiff steering, but it feels incredibly numb to me.

Originally Posted by Mango

SS already confirmed that this plate is used on the Z4M. The Z4M uses ZHP control arms. So it's use in the same manner as we would use on our non-Ms if we swapped. The biggest problem looks to be oil changes.

Maybe a small hole could be drilled in the right spot without significantly hindering stiffness?

In the Z4 diagrams on RealOEM, I don't see the same rubber isolation/joints as in the E46s steering setup. If what I found is correct,that would definitely increase steering feel.

Originally Posted by Grande D

In the Z4 diagrams on RealOEM, I don't see the same rubber isolation/joints as in the E46s steering setup. If what I found is correct,that would definitely increase steering feel.

Hmm you're right -- it uses a double u-joint instead. Wonder if that can be retrofitted

Looks like it should. you'd have to take that entire piece out of a non-M and measure it up with the rubber isolated part included vs the z4m part. good find. expensive fine though.. i wonder if you could achieve the same effect as just getting a solid coupling from one of the aftermarket vendors (if they even make one for the e46 which i'm sure they do)

^ i recall seeing posted both a solid aluminum and a polyurethane version. neither of which i was interested in