m40 intake manifold

[sh123]

Hi

Been looking for a m42 inlet manifold to go  on my m44 build.

Does anybody know if the m40 will fit? /be any good? As i cant find any m42 manifolds at all

Cheers
Sion

[Darky]

Hi Sion

There are 2 m42 inlet manifolds e36 and e30.
Also m40 inlet manifold will not fit, as it is single overhead cam ie 1 valve per cylinder and round ports.

Cheers Rohan

[sh123]

Oh, never realised it was 8v.

Im looking for the e30 m42 inlet.

Cheers  Rohan
Sion

[sh123]

Just thinking outside the box here, anybody adapted an s50/m50 intake manifold to fit the m42/44? (Due to regulations i cant run itbs)

[Darky]

Hi Sion

Yes that would work on e30 ecu. Go m50 though, m52 runners are smaller in cross section.

Cheers Rohan

[sh123]

Would this be a better manifold than the m42? Or would i be wasting time and money? 

[Darky]

Hi Sion

You would have to measure a few things to determine that answer.
1. Throttle body size of m50 inlet manifold
2. Inlet runner length
3. Port size, should be identical but not 100%.

If you get that information I'll post the e30 m42 information and we can compare

Cheers Rohan

[sh123]

Ok great rohan!

Ill do some investigation/research then

[sh123]

Is this information any good?

http://www.bmwfanatics.co.za/showthread.php?tid=21100

Throttle body bore is 64mm

[Darky]

48* 26 mm port size e30 m42 inlet manifold
50* 27 mm port s50 euro manifold

340 mm long e30 m42 runners
290 mm long s50 runners

Here are some stats

[Darky]

55* 25 mm for m50 sounds a bit high
45* 23 mm sounds right

[Darky]

Runner length m50?

This is very important, also what is the cyclinder volume of your m42 engine? Bore stroke?

Cheers

[Darky]

51.5 * 28 mm for m42/44 in itbs on this site

[sh123]

Have now been told they are 320mm long

My engine will be 88mm stroke and 87mm pistons

[Darky]

Hi Sion

How's that beautiful lightened crank going?

I think the m50 manifold is the winner then, that's a really nice length for a 2.1 and a bit of porting and polishing, but there is no way it's 55 mm in width. To high be about 50 mm.

I wonder if it would be worth wild to put trumpets on the end of the intake runners?
Another member did this on his supercharged m42, different manifold though.
Cutting the first 2 runners off and bringing the throatle butterfly in on an angle could also be of an advantage.

Take photos this is very interesting

Cheers Rohan