M50B20 manifold

[Brianmoooore]

[quote="Brianmoooore"]There's another current thread on here where someone is considering buying a complete M50B20 engine just for the sump kit, to fit a M52 into an E30.
I know a M50B20 is different from a M50B25 inlet manifold, and I know M50B25 manifolds fetch a premium these days, because of the demand for fitting them to M52B28s.
So, if someone has a 'free' M50B20 inlet manifold available, what sort of gains (or even losses) would you expect if fitted to a M52B28?

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steve_k
Joined: May 24, 2008
Posts: 5832
Location: in the vale of mansfield

PostPosted: Thu Apr 07, 2016 3:41 pm
i would have thought that the b20 manifold would be restrictive as it's the same as used on the m52b23 (also a 2.5) so as it doesn't make more power than it's bigger brother (b25)

i don't know a lot about the m5x lumps the above is about as much as i know, sorry.

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DanThe
Best Car & Mod-Master Winner 2009

Joined: Sep 11, 2005
Posts: 27156
Location: Staffs


PostPosted: Thu Apr 07, 2016 8:46 pm
I would expect a potential loss of torque due to the shorter runners, but there is not much in the diameters, the M50b20 may even be slightly bigger than the M52.

The M50B20 intake is not the same as anything fitted to m52 engines Steve

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steve_k

Joined: May 24, 2008
Posts: 5832
Location: in the vale of mansfield

PostPosted: Thu Apr 07, 2016 9:09 pm
DanThe wrote:
I would expect a potential loss of torque due to the shorter runners, but there is not much in the diameters, the M50b20 may even be slightly bigger than the M52.

The M50B20 intake is not the same as anything fitted to m52 engines Steve


my mistake i thought it was Embarassed i'll stick to playing with M20's Wink

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HairyScreech
Frequent Fragger

Joined: Jan 22, 2007
Posts: 6266

PostPosted: Sun Apr 10, 2016 9:48 am

They are different, it's an interesting question.

I think the port areas work out the same just slightly wider and flatter than the M52 manifold.

Runner lengths are close enough you would not notice a lot.

Perhaps a better option may be to fit a M54 manifold using a add on DISA controller?
Both the B25 and B30 manifolds are better than the M52 fannymold.

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maxfield
Married to the E30 Zone


Joined: Nov 27, 2005
Posts: 15027
Location: Mansfield

New postPosted: Sun Apr 10, 2016 11:02 am

A mate of mine bought an 'M50B25' manifold off eBay and had a go at fitting it himself to his E36 328i. After struggling to try and fit himself, I ended up finishing the job. Turned out to be a B20 manifold. The car did feel better to drive after although it was a tired old bus. But he smashed it up before ever going on a dyno.

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[Brianmoooore]

Just managed to delete the whole thread somehow! Managed to salvage the text, which is posted above.

A mate of mine bought an 'M50B25' manifold .Turned out to be a B20 manifold.

I suspect that he's far from the only one!

The car did feel better to drive after although it was a tired old bus. But he smashed it up before ever going on a dyno.

This is what I'm trying to establish. If a B20 manifold is available, and a B25 one isn't, is fitting the B20 a worthwhile upgrade on a M52B28.

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