View Full Version : 1991 BMW 525i E34...engine swap?
09-01-2002, 02:30 PM
hey everyone, I'm new, and I have a '91 525i...actually, not yet, but when I graduate, I will(right now it's my parents). I've been looking into performance parts for torque(turbos, SC, chips, ect.) and I've come to a conclusion...it'd be smarter to get an engine swap? I've thought about a 5.0 V12 from an 850, but decided it'd be waaaay too much modification and weight in the front. so...I've started thinking about a 540's engine? will that fit? also, the car is an auto :banghead: please, email replys to firstname.lastname@example.org thanks! -mat (1 't')
09-01-2002, 06:35 PM
The most sensible (?) engine swap I've seen for a E34 is with a E36 M3 motor. AFAIK, since the 3.2 liter ///M motor is a derivation of the M50 used in the E34 and E36, so it's kind of practical, and there's plenty of room to do the installation.
Personally, I don't see the point of it. If you're getting a good car for a good price, keep it that way until you sell it. If you go crazy with an engine swap, you better like the end result it a lot, because for it to make any financial sense, you'll need to keep it for a long time.
IMHO, I'd say drive the car the way it is for a couple years, then sell it and get something faster.
09-03-2002, 03:17 PM
yeah, I've been thinkin...I'll just use it as trade in on a 92/3 325 E36. take a few years of saving...but I think I'll like the outcome over all better. thanks!
09-18-2002, 08:29 AM
First off, forget all about this engine swap idea of yours.
Yes, it can be done but it's not practical based on the resale value of the upper eschelon cars of this vintage.
A M70B50 from a 850??? Come on! You obviously have no idea what the computer connections are like for the V12. 3 computers working on a 2 wire LAN multiplex system. Unless you're going to run webber down drafts and mechanical butterfly linkage, opting to run this engine without it's EML/DME's will cause you havoc, if you get an ignition advance system created. Also you have to have properly coded DME's. 850's came with DME's for manual, auto, and CSi configurations.
Let's move onto the e34 platform. The M60 had Nikasil lining problems when released in 1994 on in the 540,740,840 engines. Unless you find a block coded ALUSIL, stay the hell away from it. Early on BMW replaced bad Nikasil blocks with new Nikasil blocks. At about 1997 did Alusil start finding it's way into warranty repairs. Sure there are models out there with original blocks over 100k miles. But after such a swap, you don't really need this kind of grief lurking in the closet.
Your best bet is to just buy the car you want. What is wrong with the 525? I had a e34 chase up the freeway at 90mph for 3 hours. I couldn't get rid of it.
There are alot of things you can do with that 2.5 litre platform to improve performance. Besides it's damn near bullet proof and runs great. Even the e motors ran great. Just hang around the various BMW websites and learn. Unfortunately this isn't one of them. It's too new.
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