What M20 to get?

[soviet1942]

Well, my eta is slow as shit. I'd hate to admit it but its true. :(

Th whole "i" head and crap seems to be a giant hassle. What type of M20 would get the most power? i.e. m20b27 or m20b25?
I was looking on ebay and saw some m20s from a 525i, do those have more power? I was going to sell my e30 and just get a better one but it is cheaper to just fix up mine since it is in pretty good condition. I just want to make her faster with a different engine that is under $800.

Don't tell me that $100 325i part car bullshit, I have never seen one and sure as hell don't think I could find one. Unless you can show me one don't say that. :hitler:

Thanks for the help guys, feel pretty crappy knowing I can't get the best for my car.

[NC325iC]

the b25 will have more power stock, the motor from the 525 is the same

the b27 is basically what you have already(fairly sure atleast)

[kowalski]

the b25 will have more power stock, the motor from the 525 is the same

the b27 is basically what you have already(fairly sure atleast)

isn't the b27 the SETA motor?

[DaveSmed]

For the money, an M50 is the logical choice. Trust me, i'm going the M20 route and to get much out of it reliably, it adds up quicker than you think.

It's not worth the hassle to swap to a b25 from your b27 for a power bump. Might be if your engine was blown and you were looking for a replacement, but it is a LOT of work for not much power. When people say chip it, gear it, and then invest in suspension, they speak from experience.

[DaveSmed]

isn't the b27 the SETA motor?

the ETA and SETA were both designated M20B27.

[nando]

For the money, an M50 is the logical choice. Trust me, i'm going the M20 route and to get much out of it reliably, it adds up quicker than you think.

It's not worth the hassle to swap to a b25 from your b27 for a power bump. Might be if your engine was blown and you were looking for a replacement, but it is a LOT of work for not much power. When people say chip it, gear it, and then invest in suspension, they speak from experience.

I don't get it, swapping an M20 is a lot of work, but an M50 isn't? the M20 is completely drop in, while the M50 is definitely not (although it is close) - and M20s are much cheaper. for the 10whp power difference I don't see the attraction if he's on a budget.

[DaveSmed]

Much more responsive to modification is my understanding. You can throw cubic dollars at an m20 and still end up cursing your ass off at the dyno. I'm in the process of doing just this, but no engine life yet. I'm going the mega expensive painful way, NA M20. Why? in my current engine, the rings are cooked in #4 and #5. (how in just those two is beyond me)

Doing an engine swap just to go from an e to an i is way too much work. Gears and a chip are the biggest most practical gains. I hear 4.10s are a ball in an ETA around town, though obviously not the best all around solution. A moderately more aggressive ratio is a good idea though.


If you are set on M20, are budget conscious, and are looking for something worth the effort, a 2.7i might be the ticket. Especially with some gears, it will be a fun ride, though still not fast by modern standards. You will need special one year only pistons however, which sucks. You could get custom slugs made, but again, budget.