Going into the 1.8 swap project, I knew that I’d need to do a bit of welding on the exhaust. It was at that point that I decided to use the welder a bit more fully, kick the flux core stuff to the side and go straight MIG, which my welder was capable of. However, I was under the impression that the only thing needed to mate an NA “cat” / cat-back to an NB header was to change the flange angle. What I didn’t know was that there is also a nearly 4″ difference in length between the “cat” (quotes because my cat’s long gone) on the NA & NB, so a bit more work would be needed than was originally advertised.
Time to strap on my big boy pants and go to work, and actually fab something from the raw materiel, something I hadn’t really done in earnest yet, and definitely not anything requiring a welder.
There was a lot of under the car to measure > out from the car to cut > under the car to measure > out from the car etc ad nauseum, so no pictures of the assembly, but here’s what I ended up with after about 3 hours of work. It’s not bad, but there are a few gaps on the back due to a few slips with the grinder that would need fill pieces.
Taking some friendly advice, I used an arbor plate from my press to make a backing plate for the flange so it wouldn’t warp.
I was a bit torn on welding near where the flange nuts / bolts go, because that always makes assembly a pain in the butt. However, there was a pretty big gap around that hardware, and I didn’t want to put up with that much of an exhaust leak. As a compromise (with myself??) I went with welding them, and then cleaning up any excess so that the hardware would clear.
The finished product…looks a bit miserable, if we’re honest. But for a first attempt, I’m pretty happy with it. I learned a ton doing it, and it’ll do the job. No self respecting welder has ever said “look how pretty my grinds are!” Fortunately, I’m not a welder, self respecting or otherwise.
Following my usual Beat It To Fit, Paint It To Match philosophy, a quick coat of engine paint made it moderately more easy on the eyes.