I thought I would have this solved once and for all tonight, and I'm honestly out of ideas.

I have a '91 CRX Si with a '91 Integra LS (b18a1) in it. Everything was happy, birds were singing, and the car was driving, and then I got a new exhaust manifold and exhaust. The manifold went on fine, but the end flange was about 6" too far back to mate with the catalytic converter. A little creative welding on the exhaust piping behind the cat, and everything sort of fit. I drove like this until inspection time came around again.

Now, for inspection, the plan was to install the new exhaust (which went well), a new catalytic converter (which also went well), and just bolt that onto the exhaust manifold. No dice. Still too far back, even with the aftermarket exhaust (I kind of expected that, but still had hopes that it would "just work"). Called up my buddy with a welder, tried to shorten the last bit of exhaust manifold before the catalytic converter, and it failed horribly. Shitty steel being welded ends up looking like swiss cheese. Trash bin.

After some questioning and finding out how others pulled it off, StJohnscrx was nice enough to explain that the crx lower half of the manifold and the integra upper half should make it the correct length.

So, I happily ordered another exhaust manifold for a '91 CRX Si, got it in, bolted the bottom half of that to the top half of the b18a1 exhaust manifold, and now it doesn't clear the oil pan. What the fuck.

Please, give me some suggestions here. I need to drive cross-country, starting this week, and this is the difference between selling my beloved crx for scrap steel and buying a plane ticket or getting inspected and driving out west.

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just custom fab a peice of stainless steel to extend the part of the exhaust behind the cat. Cut the flange off of the exhaust extend it reweld the flange and bamm you got your extra few inches and then the flange will bolt right up to the cat.

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So you mean shorten the exhaust behind the cat, and buy another b18a1 header to replace the swiss-cheese'd bottom half of mine? Damnit, that is NOT something I'm looking forward to.

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You trashed the original header so yes you are gonna have to get another header. go to the junk yard. the second header you got wont clear the oil pan theres nothing you can do there. If the first header was too long then cut a peice out of the exhaust pipe move the cat back a few inches till it meets the header.

I thought originally that the header was shorter and the cat wouldnt meet the header but its the other way around. cut a section out of the exhaust pipe reweld the flange back on and then youre good to go. unfortunately you should have modded the exhaust pipe and not the header. Live and learn i guess.

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That's actually what I had done with the old exhaust, and it worked out terribly, the modded exhaust was the cause for the brand new exhaust. I'm going to see if I can salvage the swiss-cheese'd header, maybe even just weld in some pipe stock. I just figured that since headers are less expensive, by and large, that would be the piece I should mod. I'll let you know how this goes, keeping my fingers crossed for the time being.

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i did it to my car when i had my gsr. I had a brand new apex-i n1 cat back exhaust and a carsound cat. got a jdm type-r header which is just like the ls header and is longer than the short b-pipe gsr. All we did was cut a small section out of the new cat back pipe and reweld the flange back on. If done right its not a problem. Is there a visual inspection of your car when you go in for inspection? if not then just patch up the hole with some steel and get it to pass emissions for the time being but what i did was extremely easy.

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I think I've actually got it all straightened out. I took some fresh steel and welded it into the swiss-cheese'd space of the header. Would the GSR manifold fit the LS in a CRX directly? It seems strange that nobody makes a shortened exhaust manifold for swaps, especially considering the fact that there are shift linkages and motor mounts prefab'd.

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i think it will. and it might help you cuz it has the shorter b-pipe. it will fit the motor.

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I've heard it said (not from a reputable source, mind you) that intake and exhaust manifolds are different for vtec/nonvtec heads, and they aren't interchangeable. I need to see how the "fixed" manifold fits (it's still in NH so I can't test it yet), but I may end up buying a gsr header just to see if it works.

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actually i think youre right. they wont bolt right up. I know the intake manifold wont bolt up. Im not quite sure the exhaust manifold works the same way but it might not work.

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