2.7 or m50

[reggiebaby]

as title really what difference in power is there between a 2.7 m20 .[525e] and the m50

[oguz327]

The difference will depend on the budget you have for a 2.7 build.

[e30bmlover]

m52....

[hammoj28]

M50 or M52 definately. I wouldn't even think about it. 24v e30's are immense.

[Mayze]

IMO if your putting the time and effort into building a 2.7 then you might as well do it properly and re build the engine from the ground up which is where that would be time consuming and costly. but when you've built it it will drop strait in with just a change of chip.

Where as the M50/52 you have no need to spend money on building the engine but you do need to spend the time and money getting it in the car and running.

I'm building a 2.7 but only because I have experience building engines but none whatsoever when it comes to putting a different engine in a car. Also the m20 donk is not the prettiest engine in the world but I looks like it belongs. I know that if I put an m50 in my car I do not have the skills to get it to look factory and being anal about these things that would bother me.

More on topic as I kind of guessed that you are weighing up the options with a fresh engine rebuilt using oem parts running a stock eta crank, high comp pistons, fast road cam, mild head work and shiny manifold i would be hoping for somewhere just under 200 bhp. I don't have a big budjet but I'm not going to scrimp on parts and I'm not in a rush so if it takes me two years to finish it so be it.

[Rickz]

Whats the likely bhp from a M50 and a M52 in a e30?? (roughly)

[DanThe]

Standard M52 with the M50 manifold made 209BHP and 204LbFt or thereabouts in my old 4 door

With a decent chip and running correctly an m50 should be around 200BHP and 180ish LbFt

I wont bother posting up the results of my old M50 as the bromsgrove bunch that dyno'd it just cant be trusted

[Jhonno]

24v end of..

[Rickz]

The M52 seems like a good conversion, how expensive would it be to have the m52 in?

[Hyperion]

hi

I live in South Africa. i had my mind made up a while ago that if my current engine gave up the ghost i would be headed in the M50/52 direction.
But after looking into it i realised that i would loose my Aircon, if i went for this swap, plus the headache of getting the car registered with the new engine, issues with insurance, it would be a pain in the ass.
My vote is for the 2.7 conversion.

On another point, the power gains you can get from the m50/52 conversion cannot be ignored. If that is you ultimate goal.

regards

[DanThe]

No reason to lose the air con, all my 24v engines have ran E30 air con. Only the smaller compressor fitted to later E36's will fit though.

[zaust]

Why swap a 2.5 for a heavy 2.5 ....


2.7 / 2.8 properly or m30

[daimlerman]

I have a 2.7 M20 in my 4 door.(when the cabbie is back from the bodyshop the engine will find a new home!)
I have an M50 in my touring.....
Difficult to say which I prefer,M20 pulls from tick-over,M50 goes like a cat on speed above 3500rpm,both will return mid 30's mpg driven erm, with a light foot.
The expession on the face of the driver of a current 545i when passed by an E30 is priceless!
I expect that servicing expense on the M50 will be lower(no tappets to fiddle with)but the howl as the M20 spools up to 5000rpm is priceless.
Snag is,a s/h M50 can be bought attached to a life expired E34 for £250-£350,a 2.7 will cost at least £1500 to build....
You pays your money and makes a choice,both are right and fun to drive.

[StuBeeDoo]

For originallity, "plug & play-ness" and mid-range power, M20B27.
If you don't mind tinkering on and you want a 200bhp screamer, then you want the M5x.

[12345kevin]

Why swap a 2.5 for a heavy 2.5 ....


2.7 / 2.8 properly or m30

Exactly, so do it properley and use an M52, 220bhp with the right manifolds etc Weighs less than the old iron blocks !

[DanThe]

Have you had yours dyno'd Kevin?

[12345kevin]

Have you had yours dyno'd Kevin?

Yep, 220, exactly as Ant anticipated Had only done about 2000 miles when it was dynoed, so still a bit tight, much better now.

Going to get the exhaust finished and remove the standard 325 center section for a better flowing one after the summer, so hopefully a small improvement.

[Nay]

I like the idea of a proper 2.7/2.8 build. But the M20 engine is why I like E30s!

Your money mate, but tbh the 2.7/2.8 rebuilds should be done as a rebuild or the work will be a tad pointless. If you go that way do everything there is to do that you can afford for the full benefits!

[DanThe]

Have you had yours dyno'd Kevin?

Yep, 220, exactly as Ant anticipated Had only done about 2000 miles when it was dynoed, so still a bit tight, much better now.

Going to get the exhaust finished and remove the standard 325 center section for a better flowing one after the summer, so hopefully a small improvement.

Is yours on M52 or M50 non vanos management and has the rev limit been raised? I need to get mine live mapped to get the best from it as its still making power at the limiter, wouldnt want to take it above 7000rpm but 500 revs makes a lot of difference

[Bob_S]

out of a 2.7, m50 and m52..

I am running an m52 now and personally think it's the best of the lot.

[Ant]

@ Dan, Kevin's is on M50 non Vanos ECU , 403 iirc

most 413 and onwards with EWS need to be mapped down the diagnostic socket.

[Benho]

m52.

[DanThe]

most 413 and onwards with EWS need to be mapped down the diagnostic socket.

Is this map flashing a realistic way of doing the job properly or will I need a tuning module?