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Today I started to have a good look to see whether a whole E30 rear axle can fit on an E21. After raping one of my many 323i's I got rid of the rear axle and tried an E30 rear beam.











The axle pins are approx 20mm to narrow to get the beam on whole but I managed to "mount" the beam as a mockup with two screwdrivers... Here's what I found.

Plus
+ It's not far off fitting
+ I was concerned it might not take the height of the prop tunnel, it does
+ The beam doesn't need shortening
+ The prop tunnel is central to the car

Minus
- E21 fuel tanks aren't looking like they will fit, I had to remove the ones on this shell to get the beam into place. My car is a track based so tank in the boot is looking likely.
- The trailing arm bracket closest to the bush stops the bush from seating properly, since the trailing arms are closer to the bush. Since a custom bush will need to be made this isn't such a big deal, to get the axle as high as possible I will be cutting this bracket done.
- I reckon the exhaust will have to go under the subframe (there will be more room for the exhaust with the missing tanks though)

To get this done I will be using most likely solid subframe mounts and boot mounted tank. I reckon my exhaust I got made for my M50 will need to modified, and from Jason's axle conversion I expect I will need to cut away at the chassis rail by the spare wheel bin.

The next job is to try a complete axle with trailing arms and a diff!

Looking like it'll be a go'er for track based cars but a few too many mods for more standard cars?

cant you just chop 10mm either side out of the beam? thatd be pretty simple.
id be more interested if the wheels sit right in wheel arches? too far forward or aft?

It has been done already...
Try searching e21 s14 topic in owners gallery

Nice, I hadn't seen that conversion before, looks good! I had thought about doing something similar with the E21 mounts, and that's how to do it.

Subscribed!!!

Found the thread then

but doing that, using the e30 wishbones.... does the wheel sit right in the arches? track not too wide? are the wheels not too fore or aft? prop wise is the length needed different to standard m20?

After thinking about this a bit more I'm starting to think E30 beam centre with prop tunnel and diff mounts fabricated onto the E21 rear subframe with shortened and stronger driveshafts to replace the weak E21 shafts. Similar to how Propan does on his conversions, though he uses shortened E21 shafts. This is no doubt more work than getting an E30 subframe on the car but I'm concerned with...

the suspension geometries being off
the axle/wheels being misaligned
removing the fuel tanks
the trailing arm and brackets needing clearance to the body shell (dropping the axle down will just create more negative camber for me)
Custom rear arb mounting points

I knew these were the issues in the first place, but after having a nearly terrible accident due to an incorrectly installed rear ARB on my car there is no chance I'm taking my chances with my own alignment skills!!

Mihajlo wrote:It has been done already...
Try searching e21 s14 topic in owners gallery

I actually measured up doing it this way and I'm not sure how this guy has done it. The wider trailing arm brackets on the E30 axle won't allow the E21 beam mounting points to sit in the correct place.

His project is not finished jet but here is some pics of some other project that has been done
diff is taken of e39 M5











so, it is all lined up and where it has to be!

Wow, that looks like great work.

be and I contacting

eovako should look at the end and my rear axle, not a problem if we do take into account the measures of the rear axle

everything possible be done slowly and with the meter in the hands of

Hi

Good job, looks like the inner pickup has been relocated defiantly a lot of custom work there

Jason