BMW M50 Inlet Manifold to M52 Engine questions

[ChasR]

I have seen a number of threads detailing how to change the manifolds on the M52 engines and I am tempted to give it a go myself in all honesty. Whilst I know it will not liven the engine up much something is better than nothing .

From what I can tell:

-The manifold will give almost 20BHP to a 2.5 M52, possibly a touch more with a chip
-Some low down torque may be lost but a chip can overcome most of that
-The vacuum and possible the breather lines need to be altered to allow an M52 manifold to fit.

However, I have few (boring) questions of my own:

- Whilst it seems to be a 'bolt on' conversion for the best part what else should I bare in mind? It is mostly good news with this swap?
- Do I have to use an M50 throttle body or can I use an M52 item.
- Is there any way I can keep the ASC hooked up or will this be disabled upon me switching manifolds?
- I take it MPG doesn't take a nosedive (sorry, but the car is a daily .
- With the exception of the chip what other modifications compliment this conversion (i.e is it worth changing the exhaust and induction system (i.e an enclosed cone filter) at the same time? I currently have a single pipe exhaust being the 323i.

Many thanks .

[carat 3.6]

Would you not be better off fitting the 2.8 lump and doing the mods on that?

[ChasR]

This is one reason why I am in limbo as to what to do with this engine.

I would arguably be better off buying a 328i, but it probably would not have done half of the work that this car has (the thread details more), plus this example is quite rust free compared to many E36s out there.

If I started looking at a 328i I'd probably have my sights set elsewhere (BMW 540is seem cheap for what they are). I guess I'm just fussy .

I could convert it to a 2.8 but having a driveway to do all of my work on with nosy neighbours does limit me somewhat.

[spartacus]

I can't remember the exact details but I'm sure that all of the original gizmos will work. It'll transform the car, back in the day™ it was the most cost effective way to open up the deliberately strangled 323i. Get on one of the 3 series forums and you'll be able to find out the exact parts you need, probably but them off there too. It is better with a CAI kit but they're easy to make for this car.

[Sammo]

Info on the whats, wheres and hows:

www.bimmerforums.com/forum/showthread.php?544874-Official-M50-Manifold-Swap-Thread

Then how to actually do the swap:

www.rmeuropean.com/bmw-m50-manifold.aspx

[BenzBoy]

I've bought the M50 manifold to do this swap, Chas. I offered it up the other day and it all looked fairly simple, although my breather hoses were a bit of a cut-and-shut from M50 bits anyway, so maybe your stock 323 will differ.

I've read about big-bore throttle bodies but the power gain doesn't justify the costs, to me. Maybe if you were wringing every last horse out of the car.

I can recommend a K&N cone filter, even if it's just for the induction noise. It probably doesn't give all that many more horsepowers over stock but the sound is really nice.

Most opinions on the net seem to be positive about the manifold conversion. Yes you lose a bit of low-down torque in exchange for 20bhp but as you probably know the party really starts above 4k rpm with these engines anyway!

I can recommend Endtuning on bimmerforums for all things ECU - really quick service when he did my ECU ready for the transplant. I don't know what his remaps are like but his service is first class and he has a good rep. He's in your neck of the woods too I think?