M50 manifold on an M52 2.5l?

[navvid]

96-99: M3
96-98: 328
99: 328is

Cheers Budda.

[navvid]

Last night I pulled my stock manifold and noticed that the M52 throttle body houses the orange ring gasket and there's only a shallow channel for it to seat in on the M52 intake manifold. But the M50 intake manifold has the deeper channel to house the gasket and there's only a flat seat for it on the M50 throttle body. So when swapping in the M50 intake manifold, which side should I set the gasket in? Another thought is to leave both in and just let them seat against each other, but that seems a little ill advised...

[pbonsalb]

There is a deeper gasket for the M50 and a metal plate that most people use. Bimmerworld and others sell it.

[thenavybimmer]

This is to the OP: While we are comparing apples to oranges, (I have an s52 w/m50 manifold), and I do not have a dyno graph to justify, (just seat-of-my-pants experience) using a bigger throttle body makes a huge difference. When you take apart yours, you can see the difference in the size of the inlet from the size of the throttle body to the manifold. It is a huge, visible difference.
Also, I am unsure of obdII, but when I did my engine swap, Zionsville Motorsports told me that the ECU will adjust to the bigger engine, and the m50 manifold. (and most changes to the engine, as the original BMW tune is very flexible) (I only reflashed the ECU to make sure the 3.5 MAF would work.)

[navvid]

I tried installing the M50 manifold early Sunday morning after I finished my transmission swap, but I found out that it does not quite "bolt on". Well, the manifold bolts on, but there is a little more to it than just a gasket adapter plate and an air hose y-adapter. The bolt hole spacing on the M52 fuel rail does not match the M50, and the oil separator has clearance issues with the bracket bar beneath the manifold. As I said, I'd been wrenching all night, and was pretty tired, so I gave up fairly quickly. What solutions have you vets worked out to these problems? My friend tells me the kit he bought came with little brackets that compensated for the difference in the fuel rail bolts, and I can probably fab something like that up pretty easily... What about using the M50 fuel rail? I have one of those as well... And what about the oil separator? Can I use the M50 separator as well? Should I just ditch the support bracket below the manifold? It doesn't match the M50 manifold bolt holes either. If I eliminated it, that would give me enough room to properly mount the stock separator...

What else have you guys done? I have been looking through the tutorials and walk throughs that I found online, but haven't been able to find a good, comprehensive set of instructions.

[mr ilia]

If you haven't seen this yet.

http://www.bimmerforums.com/forum/sh...ld-Swap-Thread

[navvid]

Given that I have the fuel rail from the M50, it seems the easiest solution is to use that one. I can fabricate little adapter plates like the ones that come with some of the kits I've seen, but if the M50 rail will bolt on, I like that better in theory. Seems like a much cleaner solution... is there anything I'm missing? Any reason it won't work?

[pbonsalb]

M50 rail requires block off plate at FPR end in order to be used with OBD2 FPR and if you bypass OBD2 FPR instead you will get a code (unless you leave the wiring harness plugged into the old FPR). Bimmerworld sells blockoff plate for $25. Easiest is to use OBD2 rail with little extensions off the manifold mounts to the rail. $2 hardware store parts you can cut and adapt and drill. I ran exactly this for 7 years with no issues. You can get a peak of the front adapter tab in the picture below if you are on a computer with a proper screen.

Attachment 535701

[navvid]

Thanks Phonsalb. What do I do with the support bracket underneath the manifold? Should I just eliminate it? That is what I was planning on doing...

[pbonsalb]

There are 2 support brackets. I still gave mine. I was able to move them a little so they still fit. I did have to make an adapter off the rear one to home the dipstick tube. Some people don't use the supports at all. I think at least one would be a good idea.