My Bastardized E36 5-Lug Conversion

[BenM]

Going to try one more thing for the Rear setup that 318ti.org suggested before I pull all the suspension off. Apparently the E36 M3 rear caliper bolts fine to the Ti Rear Trailing Arm, the problem lies in the e36 m3 rotor being too large.

The solution (hopefully) is to run E46 323i Rotors (276mm x 19mm). This will allow the E36 M3 Rear Caliper to clear the rotor diameter (276mm vs. 312mm) as well as being a similar thickness to the stock M3 rear rotor (19mm vs. 20mm) as to not hyper extend the caliper's piston.

Someone on 318ti.org has already successfully bolted an M3 rear caliper to a Ti Trailing arm with a stock 272mm x 10mm rotor. The problem with running stock Ti Rotors is that 10mm spacers are needed on the pads to compensate for thinner non-vented rotors.

M3 rotors are larger in diameter and thicker(being vented) than the ti rotors. Yes the calipers bolt right up to the ti trailing arms. However, if you tried to mount an M3 rotor onto the hub, the caliper will sit too low and will hit the rotor before the bolt holes will line up. Therefore, you'd have to use rotors that are the same diameter as the ti rotors. The 318ti's non-vented rear rotors are 272mm in diameter and 10mm thick. E46 323i and 323Ci's(not to be confused with e36's) use a 276mm X 19mm vented rear rotor. This means it's only 4mm larger in diameter than the non-vented 318ti rotor. The M3 caliper may or may not clear the E46 323i, 323Ci rotor. The E46 rotors are 19mm thick(being vented) which is really close to the thickness of e36 M3 rotors. E36 M3 rotors are 312mm X 20mm. So in short, if me and Bluebimma's theory is correct, you should be able to run M3 calipers with E46 323i/323CI rotors on the rear. Very important though, don't confuse the E46 with the E36. The E36 323i's use non-vented rotors.

I deleted my other post, but if you use ti rotors, you'll need to add a spacer to the brake pads to compensate for the thinner non-vented rotors. This would be to prevent the piston from hyperextending. Tony mentioned possibly using an old brake pad backing plate. Personally I like the idea of upgrading to e46 323i/Ci vented rotors better though.

[BenM]

No dice. I guess the 318ti rotor mounts rotor surface way further inboard, which doesn't even come close to allowing the E46 323i rotor to match up with the caliper carrier. For now I guess the best solution for using E36 M rear stuff is to use a 10mm spacer on the other side of the pad. Going to try and machine a spacer up tomorrow, to match up with the pad and also utilize the holes on the caliper.

Edit - some more info on why the E46 323i rear rotor (or thicker rotor) will not work.

Although the E36 M3 Caliper will bolt to the 318ti Caliper Carrier with no problems, the E36 M3 Caliper Carrier does not bolt to the 318ti Trailing arm. The distance between the threaded holes on the E36 M3 is more than that on the 318ti, so both bolts cannot be used and therefore not work. Now the E36 M Caliper will bolt to the 318ti carrier which is great, but the 318ti caliper carrier is only sized for a 10mm rotor, therefore you are limited by that as well.

Hope this helps some people, I'll post up some pics tonight and will be working on a spacer tomorrow!


E36 318ti rotor (left) vs. E46 323i (right) rotor

[bimmer630]

Yo man, you stole my strut color idea lol

http://www.r3vlimited.com/board/attachment.php?attachmentid=29468&d=1274399252

[brianao34]

Update...

[TSI]

Bump this! Would love to see the outcome...