M50 manifold from M54b25 engine onto b30 engine.

[andypickup]

I'm looking to squeeze a few extra HP out of my 2003 3.0 e85. I saw a few articles and videos of people advising a m50 inlet manifold could give 40hp. My engine is the M54b30.

Is it straightforward or would I have to get the head off and port match, upgrade cams etc?

If anyone has already done this I'd love to know the process and what other parts you needed to swap/upgrade.

Thanks in advance.

[brillomaster]

I thought the m54 was already fairly well optimised... the m50 manifold normally goes onto the m52 engine, which despite being a 2.8, makes a very restricted 192bhp.

But the m54 3 litre still makes a good 230bhp as standard. What i dont know is how the 3.0si makes 265bhp, also from a 3 litre... ?

[kis]

My engine is the M54b25.

B30 surely?

[andypickup]

My engine is the M54b25.

B30 surely?

Sorry, should have re-read that. I have the b30, it's the manifold from a b25 I'm investigating fitting. I'll amend this now. Thanks for the heads up.

[kis]

Oh right okay! Makes more sense

I've not come across this before on the forum? Have you seen it done on the e46 platforms?

[GuidoK]

What i dont know is how the 3.0si makes 265bhp, also from a 3 litre... ?

Maybe because its a completely different engine?
The M54 and M52TU are very much related (brother...sister...) but the N52 lives on the other side of the globe.

But anyone who thinks a M50 manifold swap is going to give an extra 40HP lives in a fairy tale.

[brillomaster]

What i dont know is how the 3.0si makes 265bhp, also from a 3 litre... ?

Maybe because its a completely different engine?
The M54 and M52TU are very much related (brother...sister...) but the N52 lives on the other side of the globe.

But anyone who thinks a M50 manifold swap is going to give an extra 40HP lives in a fairy tale.

Yes but i mean, both m54 and n52 are naturally aspirated 3 litre straight six engines, so what did the change with the n52 to get an extra 35 hp? Usual trick is a higher redline, but are there any other factors?

[Pbondar]

N52 is later design...truism of life that later designs can deliver more bhp per litre..also had variable lift valves and more sophisticated inlet manifold plus collective experience of earlier designs...

https://en.wikipedia.org/wiki/BMW_N52

[GuidoK]

Yes but i mean, both m54 and n52 are naturally aspirated 3 litre straight six engines, so what did the change with the n52 to get an extra 35 hp? Usual trick is a higher redline, but are there any other factors?

N52 has a higher redline: 7200rpm vs 6500rpm I believe.
But the n52 has variable valve lift, completely different cam setup and ecu.
Cams are even hollow (flow formed).
Different exhaust manifold
Different head allltogheter.
Different bore/stroke
Different compression ratio
And who knows what differences lie in thermodynamics of the block and cylinders.

You can look at redline for HP curves (although that doesnt say anything; most of the time peak power is not made at redline.
To get a feel for the efficiency of the engine, you can also look at torque curves or peak torque.
N52 has 15Nm more torque, so overall a more efficient/powerful engine per displacement (5%)
The rest is done with extended curves.

The M54 was the last iteration of a long line of engines partially dating back to the early 60's that was constantly improved and redevelopped in an evolutionairy way (the m54 still uses some parts and key measurements also used in the 4cyl m10(!), like bearing sizes etc).
The N52 was designed from the ground up, and stands somewhat on its own. In a certain way, the following N54 turbocharged engine has again some traits that the m54 again had, going back to a closed (or semi closed) deck block instead of the n52 open deck.