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M20 swap: Exhaust Manifold

Posted: Tue Feb 04, 2014 9:26 am
by Eddie.
Basically, I'm trying to figure out what manifold to use for my M20B25 swap.

My understanding is that the E30 manifold won't fit around the steering linkage, and the E21 6cyl manifold doesn't match the exhaust ports on the M20.

Fortunately, I've got a series 1, so no silly brake linkage to work around.

Is there any "off the shelf option" (I'm guessing not) or what have people done in the past? At the moment, I think I'm favouring cutting and modding an E30 manifold, but I'm open to suggestion.

Cheers.

Re: M20 swap: Exhaust Manifold

Posted: Tue Feb 04, 2014 10:05 am
by rob0r
I never considered the M20B25 exhaust ports were different to the E21 exhaust manifolds, I've pulled apart a few M20B25 E21s and they all had the standard E21 M20 exhaust manifold. If I remember I'll check again.

Re: M20 swap: Exhaust Manifold

Posted: Tue Feb 04, 2014 11:37 am
by Jeroen
I'd suspect the E30 manifolds to be larger because of the larger ports in the E30 head

Re: M20 swap: Exhaust Manifold

Posted: Tue Feb 04, 2014 9:25 pm
by drjim
As per my PM I just used the one off the 2.0 auto that was in my car when I got it. Ports don't match but it still works.

Re: M20 swap: Exhaust Manifold

Posted: Wed Feb 05, 2014 9:23 am
by Eddie.
Yeah got your PM, nice one.

Looks like I'll head down that route then I guess.

Re: M20 swap: Exhaust Manifold

Posted: Wed Feb 05, 2014 6:33 pm
by drjim
Shouldn't be too hard to open out ports on manifold with a die grinder, I just haven't had time.