Progress on B17 swap and question about exhaust

Hi everyone, swap is coming along (B17 in to 91 da OBD0). Motor and tranny are in everything is plugged in and ready to start today. I put a DC header on and it does not reach to the exhaust. I knew there would be some fitment issues, but now my question is what is the best course of action to get it to fit? Should I just drive it to a muffler shop and have them weld a piece to the exhaust so that it fits to the header?

Thanks for all your help and encouragement to this point… Specifically Colin and friends :salute:
I will post some pictures in a few minutes if anyone wants to see what I have going on. Thanks again.

Exhaust shop should be able to make you a coupler real quick for this. I doubt it would run any more than $50 at most.

Unless you have a friend who knows how to weld then a muffler shop is going to be what you want to do. And if you plan on getting a better header and a high flow cat this would be a good time to do it all at once so you can save some labor on making it all fit. My personal preference of how to fit all of this stuff and provide the best future options is to get a good 2.5" collector header. Generally these are fitment for newer b series cars and are more compatible than anything made for the DA. Then use a standard cat back exhaust made for a DA. Then get a highflow cat made to be the right length for those two parts. That way your header and exhaust are not custom, they’re just off the shelf parts that you can buy, replace, sell…etc easily and the only custom part to the whole system is the cat.

Awesome thanks guys. I think since I just have the stock exhaust for now I will get that welded then later on get an axelback setup. 50$ sounds amazing I was expecting 200$ range. Anyway I hope to hear this thing run tonight1

It really depends on where you live and what the local shops charge. I know around here there’s no way I could get something like that done for $50. Maybe if I spoke Spanish and could go to one of the shops in the ghetto. Just be sure to tell them what you want them to do, don’t let them decide. If they decide what to do they’re likely going to do what’s fastest/easiest, not what’s best. Often shops will just permanently weld things instead of installing flanges - then next time you remove your exhaust you end up having to cut it off.

So to be clear I want to have them install a flange before the Cat?

It really depends on what YOU want them to do. Your system is fully flanged now so that the exhaust, cat and exhaust manifold can all be separated and removed independently. If it were me I’d want to keep it that way.

I’m sure there are other options, but the 2 that come to mind right now:

  1. Modify the cat to lengthen it. Cut off one of the flanges, weld in a small section of piping to make up the length needed, weld the flange back on.
  2. Fabricate an adapter that will fit between the cat and exhaust. Most aftermarket exhaust systems had an optional adapter for use on 92-93 vehicles, so basically you’d be making one of those. It would look something like this:

I like option #1 better because it seems “cleaner” to me and weighs less. But if you ever think you might go back to a header designed for a 90-91 then the adapter may be a better option for you.

Colin thank you I’ll take this information and make a decision. By the way I just drove the car! It started and was idling high but got it adjusted. And apparently the shift linkage wasn’t on properly cause I lost all gears. Put it back on and drove it home. Thanks for all your help along the way.

Now to clean it up and get my buddy over here to pull the engine codes. It’s got a check engine light which I expected. Could be the 02 on the exhaust. Anyway till tomorrow!

You’re very welcome, and good luck!