E36 328 track car build - Rear Suspension

[Z-Thrizzle]

I'm planning to start the build by reinforcing the rear trailing arm pocket and changing bushings throughout. Before diving-in, should I look into getting M3 trailing arms or are 328 arms fine? What are the advantages of using M3 arms...is it just being able to run larger diameter rotors?

[bluptgm3]

Upgrade to the M3 subframe reinforcements, in addition to the RTA pocket reinforcements. Add the rear sway bar reinforcements on the rear subframe

The change of RTA from the 328 to the M3 RTA mandates a change to the larger M3 calipers, which causes a mismatch with the 328 front calipers.
The benefit would be larger wheel bearings, but those need to be matched with the M3 rear axles and M3 output flanges.

M3 rear calipers will not bolt up to 328 RTAs, though I recall reading something about E46 330 calipers fitting the E36 328.

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[Z-Thrizzle]

Upgrade to the M3 subframe reinforcements, in addition to the RTA pocket reinforcements. Add the rear sway bar reinforcements on the rear subframe

The change of RTA from the 328 to the M3 RTA mandates a change to the larger M3 calipers, which causes a mismatch with the 328 front calipers.
The benefit would be larger wheel bearings, but those need to be matched with the M3 rear axles and M3 output flanges.

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Thanks for the info....this is really helpful. Parts from a Z3M will be moved over to the 328.
So I will have M3 brake calipers available but am not sure if the rear calipers would fit the 328. I will test fit when the partout begins.

[bluptgm3]

Z3Ms have their own Rear Calipers - 34212228443 / 34212228444 on Rear Caliper Carrier 34112226875.

E36 M3 Rear Caliper - 34212227519 / 34212227520 on Caliper Carrier 34212227521.

To the best of my knowledge neither can replace the 328 Rear Caliper - 34116758113 / 34116758114 on Rear Caliper Carrier 34106758104.

However the Z3 Non-“M” does share the same Rear Caliper 34116758113 / 34116758114 on Rear Caliper Carrier 34106758104 with base E36, base E46, base Z4, etc., etc..


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[Z-Thrizzle]

Z3Ms have their own Rear Calipers - 34212228443 / 34212228444 on Rear Caliper Carrier 34112226875.

E36 M3 Rear Caliper - 34212227519 / 34212227520 on Caliper Carrier 34212227521.

To the best of my knowledge neither can replace the 328 Rear Caliper - 34116758113 / 34116758114 on Rear Caliper Carrier 34106758104.

However the Z3 Non-“M” does share the same Rear Caliper 34116758113 / 34116758114 on Rear Caliper Carrier 34106758104 with base E36, base E46, base Z4, etc., etc..


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Thanks I will be getting M3 RTA and cv axles. The 328i is an automatic so I picked up a manual M3 driveshaft to run a 5 speed. From my understanding this should work by only swapping the front section of the driveshafts.

The Z3Ms use the same rear caliper carriers. https://www.realoem.com/bmw/enUS/par...&q=34212227521