M20B25 vs. M50 into a 320i

[Archetype]

Here's my current project thread - http://www.gpforums.co.nz/threads/48...6#post10123906

I need some advice on what path I should follow in terms of getting this old worn out hunk of junk B20 out of the car.

I was all ready to buy an M50B25 and matching 320 box. But reading around some of the threads (this one in particular - http://www.r3vlimited.com/board/showthread.php?t=309450) it seems it may be worth buying an M20B25, rebuilding and running a low boost set up. I wouldn't want to be pushing more than 2-300hp ever.

What's your guys thoughts? Bearing in mind I'm a mechanic so parts are at cost + labour charges will be next to nothing (other than possibly some block/part tests done at the recon guys).

[jlevie]

If you are trying to build a "beast", a built and blown M20B25 will beat a stock M50. But a built and blown M50 would be even better. There is really quite a bit of magic in a stock M20B25 that is running like it is supposed to.

[TobyB]

The M50 is a 4- valve DOHC engine. It's a full generation newer head than the M20.

And it doesn't have rockers.

But it never came in an E30.

Up to you...

Me, I like the M42 because it's cheap to run, and also makes good power up high.
SO I feel a little F1, but spend not so much.

t

[lukeADE335i]

As you are a mechanic - a chip, hotter cam & some headers in the M20B25 will give it the same performance as the M50B25 & require no additional wiring or anything else in the 320i & bolt straight up to your existing gearbox.

[E30NJ]

I would say do a M20 turbo. Reason being, its a little easier, (wiring harness and electrical) plus everything is there ready to mount. Heres a sick video of this guys M20 turbo: http://www.youtube.com/watch?v=adU1V9aiZqM