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Discussion Starter · #1 ·
I've seen a lot of stuff written about the manifold conversion, but I've got some questions about which one is needed.

I've got the manifold off a late E34 2.0 and it appears identical to the pictures of the M50 325/525 manifold, the ports would have no space for gaskets if they were any larger. If you check the RealOEM site, the part numbers are the same for the 520i and 525i E34, and the E36 320i, the E36 325i has a different number. I've tried a search for the number that's cast into the manifold below the opening for the throttle body on mine, but couldn't find anything.

Is it the port spacing, or volume of the two litre manifold that stops it being effective? Why do some say the 2 litre manifold can't be used, and isn't this contradicted by the part numbers? Could it be there were a series of manifolds used over the production run of the M50 engine and some fit and some don't?

Part number: 11611738940

E34: Details on E34
E34 525i Sedan, U.S.
E34 520i Sedan, Euro
E34 520i Touring, Euro
E34 525i Sedan, Euro

E36: Details on E36
E36 320i Sedan, U.S.
E36 320i Coupe, Euro
E36 320i Convertible, Euro
E36 320i Sedan, Euro

Part number: 11611735727 is only fitted to M50/S50 2.5 litre.

I've also read of manifolds ending in 727, 728, 730 and possibly 612 being ok.

It's quite confusing.
 

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Platinum BFuk Member
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588 Posts
I've seen a lot of stuff written about the manifold conversion, but I've got some questions about which one is needed.

I've got the manifold off a late E34 2.0 and it appears identical to the pictures of the M50 325/525 manifold, the ports would have no space for gaskets if they were any larger. If you check the RealOEM site, the part numbers are the same for the 520i and 525i E34, and the E36 320i, the E36 325i has a different number. I've tried a search for the number that's cast into the manifold below the opening for the throttle body on mine, but couldn't find anything.

Is it the port spacing, or volume of the two litre manifold that stops it being effective? Why do some say the 2 litre manifold can't be used, and isn't this contradicted by the part numbers? Could it be there were a series of manifolds used over the production run of the M50 engine and some fit and some don't?

Part number: 11611738940

E34: Details on E34
E34 525i Sedan, U.S.
E34 520i Sedan, Euro
E34 520i Touring, Euro
E34 525i Sedan, Euro

E36: Details on E36
E36 320i Sedan, U.S.
E36 320i Coupe, Euro
E36 320i Convertible, Euro
E36 320i Sedan, Euro

Part number: 11611735727 is only fitted to M50/S50 2.5 litre.

I've also read of manifolds ending in 727, 728, 730 and possibly 612 being ok.

It's quite confusing.
As far as I'm aware, the port spacing of the 20i is the same, but the M50 25 manifold has the biggest volume.

A 323 or 328 manifold allows less airflow through. Basically, you want the manifold off of a 25i model producing 190 bhp. Air pipes are different between models and ASC. What car are you doing the mod on?
 

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Discussion Starter · #3 ·
It's to go on an E39 with an M52 single vanos 2.8 motor.

The parts numbers suggest the manifold on the 190 bhp e34 525i was the same as the e34 520i, that's the grey area.
 

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Platinum BFuk Member
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It's to go on an E39 with an M52 single vanos 2.8 motor.

The parts numbers suggest the manifold on the 190 bhp e34 525i was the same as the e34 520i, that's the grey area.
If you're sure the part numbers are exactly the same, then it's the right bit. Then larger manifold's internal diameter nearly reaches the rubber gasket, but the smaller manifolds have 10mm or so of plastic, reducing the inlet size.
 
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