M50 2.5 24valve conversion

[MaK-71]

I saw a E30 motor recently that had a E36 M50 2.5 24valve conversion.
220BHP!!?

Interesting conversion as it wasl still a 2.5
Is this a fairly straight forward swap????

I take it
you would have to change the prop and diff also to E36. Or have the E36 prop cut & welded to fit E30 diff??


Cheers Mak

[jmc330i]

Its not a difficult swap - do a search for M50 or M52, that should find all the threads about it.

The diff and prop used depends on the gearbox choice. The E36 diff will not fit, so either an E30 M3 diff or normal E30 diff is used depending on the ratio of the E36 gearbox.
The E30 box can be used although it rotates the shifter slighty.

I think 220bhp from the 2.5 M50 would take a bit of work - the 2.8 M52 is easier to get power from by fitting some 2.5 bits and pieces - intake manifold and TB spring to mind.

[Brianmoooore]

Easier to start with the E34 525i motor, as it has the right sump to fit the E30.
192bhp is the factory output for one of these engines, but if you use the single vanos engine it feels a lot more!
E36 diff doesn't fit, but smaller engined E28 ones do, if fitted with the E30 rear cover and output flanges.
! found mine in a 525e, which was a 3.15, IIRC.
2.7 litre M20 short engine from this car didn't go to waste either.

[Geeman]

Brain... how much is a 525e bottom end worth?

And using a 525e diff (which is non LSD) will produce what results? Low revs and a high top-end or high revs and a low top-end...?

Giles.

[M5pilot]

220 bhp from the M50 isnt that hard. In fact they are capable of more than this once cams are added.

The M52 is capable of well over 230bhp as proven time and time again on e36coupe forum.

One guy has got over 250bhp - Alpina527 325i inlet manifold and throttle body upgrade, US M3 spec cams, Exhaust, some sort of induction kit and some other fettling I cant remember. he has been working on his car for some years now and has dyno plots from the same place to prove the gains. Very impressive!

The m52 2.8 swap is well worth the effort and doesnt cost an arm and a leg to do.

[jmc330i]

And using a 525e diff (which is non LSD) will produce what results? Low revs and a high top-end or high revs and a low top-end...?

The 3.15:1 diff will give low revs and high top end. If fitted to a 325i M20 box, I doubt the 325i would pull away that easily because of the gearbox ratios, but it would have a high top end - if it could ever get there

220 bhp from the M50 isnt that hard. In fact they are capable of more than this once cams are added.

The M52 is capable of well over 230bhp as proven time and time again on e36coupe forum.

I didnt realise the M50 could be tuned that much - without a large amount of cash that is. I thought the M52 was easier to get power from because its a more restricted engine from the factory, hence using the M50 2.5 bits.

[DanThe]

Am I right in saying an E36 diff can be rebuilt into an E30 casing? Im sure ive read it on here somewhere

[jmc330i]

Yeah, Ive read that as well. I think the internals (or atleast some of them) can be used in the E30 casing but Im not sure what bits can be used.

[Brianmoooore]

Am I right in saying an E36 diff can be rebuilt into an E30 casing? Im sure ive read it on here somewhere

Think it can be done, but setting up a diff is a specialist job.

[Brianmoooore]

Brain... how much is a 525e bottom end worth?

And using a 525e diff (which is non LSD) will produce what results? Low revs and a high top-end or high revs and a low top-end...?

Giles.

No idea what a 525e bottom end is worth. I paid Ԛ£20 for the engine and the diff, but that was from a scrappy rather than a breaker. I was offered a complete 525e for Ԛ£100 a couple of years ago.
Multiply your favourite E30 diff ratio by 0.81 to find the ratio you need with an E36 or E34 box. I.E. if you run a 3.64 on an E30 box, then you need a 2.95 with an E36 box.