[Rickyshucks]

I swapped off my 325i stage 1 manifold for a stage 3 im however I noticed that the ports are smaller on the upgraded manifold. I am curious as I believe mine came off a 323i in the Canadian market (2 disa's).

I feel a slight difference however tune coming soon will help. Just curious about the port sizing.

[hassmaschine]

Could be a difference on the 323i - normally, all N52s had the exact same ports.

[rjahl]

Originally Posted by hassmaschine

Could be a difference on the 323i - normally, all N52s had the exact same ports.

I thought the 323 has the 2.5 liter N52 six cylinder. That would use a smaller intake tube.

[Rickyshucks]

Originally Posted by rjahl

I thought the 323 has the 2.5 liter N52 six cylinder. That would use a smaller intake tube.

Damn. So I am assuming I am missing out on some power then.

[Rickyshucks]

Got a response from johnmyster that Ill share for the public..

johnmyster 09:12 AM Today
I saw your thread. Yes, it seems that in other markets, the smaller displacement N52 motors got the 3 stage manifolds...but the intake runners were smaller to match smaller intake ports in the head. in the US, everything was B30 but detuned by software and manifold.

I’m not sure what it would mean in terms of power output. If properly tuned smaller runners could increase cylinder filling at lower RPM than larger runners.

[The Nightman]

I've always wondered why the PN for the 3IM on Canadian 323 was different (11617559525 instead of 11617559523). To add to the confusion, European 323 uses 11617559526...

http://www.realoem.com/bmw/enUS/show...diagId=11_3756

[Rickyshucks]

The 323i stage 3 im in Canada is off a n52b25. It also has smaller bore (82mm vs 85mm on 330s). I am going to take a side by side once my stage 3 from a n52b30 comes!

Originally Posted by freedomfries

I've always wondered why the PN for the 3IM on Canadian 323 was different (11617559525 instead of 11617559523). To add to the confusion, European 323 uses 11617559526...

http://www.realoem.com/bmw/enUS/show...diagId=11_3756

[Rickyshucks]

Bottom off a n52b30

Top off a n52b25 (Canadian 323i)

[CobraMarty]

Makes sense, smaller ports for the smaller engine.
Smaller ports might make more TQ and less top end HP on the 3L.

[hassmaschine]

Probably the head has smaller ports too, so you dont want a 3l manifold because there will be a big step up into the head.

[Rickyshucks]

Originally Posted by CobraMarty

Makes sense, smaller ports for the smaller engine.
Smaller ports might make more TQ and less top end HP on the 3L.

It does. There was just a debate about the Canadian 323i being THE EXACT same as a regular 328/330 stage 3. Other than port sizing, everything else is the same. Still decided to buy an actually n52b30 mani

[PORTMOODY]

Originally Posted by hassmaschine

Probably the head has smaller ports too, so you dont want a 3l manifold because there will be a big step up into the head.

different cylinder head part numbers between the same model years and no 3.0L n52 shares the part number in its history, so you may be right.

http://www.realoem.com/bmw/enUS/show...diagId=11_3734

http://www.realoem.com/bmw/enUS/show...diagId=11_3734