[kartracer76]

Hello!

I'm rather new here and I need some help. I will be purchasing a 1985 BMW 320e for use as a GT car. The current engine in the chassis, an M20B27, has a knock and a few other issues; insuficient power being one of them. I will be purchasing an M50 engine (I do not know which model) and installing it. The seller of the car has assured me that the engines will swap with the only modification needed being movement of the brake booster. Is this correct?

Also, would I have to install a new computer in the car or could the existing ECU be reprogrammed to work with the new engine.

Any info on swaping from an M20B27 to a M50 (Whichever model would likely fit) would be greatly appreciated.

Cheers,
kartracer76

[e90pilot]

You're in the wrong section. This is e90 non turbo (N52) engine. But my friend tried to do this. I recommend an M52 (less troublesome). You need to change the brake booster and a few engine/tranny mounts. Also, you can upgrade to an e36 steering rack and ABS servo. There's a website that sells all the retrofitted parts and has instruction for a DIY. I'll hunt it down for you.

[C ///M]

Wow, I don't know where to start... Never thought I'd see an E30 M50 swap question on an E90 board.

The E30 M50 swap in all honesty isn't an overly complex upgrade, but judging from your questions, I think it may be well beyond your scope. I don't mean that to sound like a dig, but it's much much more involved than just a booster swap.

There a quite a few different routes you can go, but I'll give you a typical install. I'm going from memory here, so I may forget a few specifics, but in a "nutshell":

-E34 M50 Oil Pan, Sump, and dipstick need to be used for correct fitment in relation to the front subframe.
-Use E36 motor mounting arms with E28 535i motor mounts, installed in the normally unused (outside) mounting holes in the subframe mounting ears.
-You need a brake booster with an overall smaller diameter to clear the intake manifold, either from an e21 320i, 2002, or the double booster from the e30 325ix.
-The heater core coolant hoses in the firewall near the booster will need to be slightly bent downward. Careful not to break these or you're in trouble.
-If you use the e30 getrag 260 tranny, it will be rotated 15-20 degrees when bolted to the block. The cross-member will need to be modified to support this mounting, in addition to a modified shift linkage/etc. A better choice is trying to pick up the ZF320 that came with the M52 and S52 setups. Remember upgraded tranny mounts to support the extra weight. Also, if you go with the ZF, you'll need an E30 M3 driveshaft. (there are a few different options here...)
-You'll need a matching ECU for whatever motor you choose, silver label 413's are pretty easy to get, but remember to get a chip that disables EWS. Red label 413's don't have EWS. If you go with an S50, the 506 ECUs don't have EWS either.
-I'm not going to get into the OBDI swap info if you end up going with an OBDII motor, but you'll need an OBDI M50 engine wiring harness and a custom wiring harness adapter to connect the engine wiring harness to the e30 body harness.

Ok, instead of me continuing, if after reading this far and you're still interested, then there are some very in depth resources online that you need to go to. www.r3vlimited.com has subforums devoted to all things 24v swap related. There's also a wiki for the swap too, but I've honestly never read it and don't know who's contributed to the info. If you decide to go for it, it's definitely a rewarding upgrade.

[Kylekuu]

try bimmerforums, they have it down to specific models; and ppl there has done swaps. I did my research there for my 84 back then, there are more things than just the brake booster