Z3 M52 in 1991 318is (California BAR)

[Jean]

Even if, say I BAR it as an e36 swap rather than a Z3 for purely exhaust fit reasons?


Well, the thing is, they're going to ask for proof it's a California emission certified engine its a very recent rule that's been put into place and honestly I can't say what the ref is going to do if you have e36 stuff under there. You could always call and ask a ref, they're very helpful. I know an OBD2 e36 has 4 oxygen sensors, one in each exhaust manifold and two post-converter. Real OEM shows the Z3 has one 02 pre-cat and one 02 post cat. This is where you'll have issues if you're running an e36 mid pipe. If you look at the Z3 emission label it should tell you the number of 02's so you can verify what is shown on realoem.

You could, go to the junkyard and pull and emission label from a 328i and hope he doesn't verify the vin that's on the back of the cylinder head(if it's even there, its was on my m50) which he might not because he probably doesn't know its there. If he does and he looks it up in his system and sees that it's been smogged as a Z3 its whole life you might have issues.

Interesting, I didn't have to do this last time I went through BAR. Will have to look into it myself now too

[mjweimer]

I used the Syncro Design Works downpipe which is designed to work with the stock FCAB's and ends in an S-bend so you can attach you own custom exhaust (they also sell a complete front to back exhaust but I have other plans).


Since you are going to do a BAR cert and need a factory center section, I think you will be limited on clearance and will need to run Treehouse style FCAB's. I have no specific experience with this but many on this forum will and there should be some documented installs.




MJ

That's great news!! I gave up hoping that someone would chime in as it seems like Z3 information is limited. Thank you!

This means it'll fit like the e36 ones, which means I probably need to get some Treehouse style FCABs then?

[Codym42]

I have the same setup as MJ. I also have a '97 Z3 m52 in my e30 and am using the stock manifolds. I went through the same search and couldn't figure out why the part numbers were different from an e36. Markert Motor Works used a Synchro Design Works downpipe on mine and had no issues fitting it to the Z3 manifolds.