Got some work done on the exhaust. I underestimated how much of a pain in the ass this was going to be, but I think I've got the hard part done.
My biggest unknown was getting the flare made for the header connection. Since I got 2.5" tube instead of 2.25", I was able to just cut the flare off the old midpipe and use it as a tool in the press.
This worked surprisingly well. It's a bit less rounded than the original, but it looks like it will work just fine.
I was able to re-use the original flange as well, just had to squeeze it a bit in the vice and grind off just a little bit of material to get it to fit the tube right. Painted it as well.
My welds are definitely not pretty. This was my first time welding stainless. In hindsight, I should have just gotten mild steel. Its a lot more difficult to work with.
Here is the midpipe finished up. Lots of compound angles and curves so it had to come in and out a bunch of times to get it just right. As you can see, I opted to move my catalytic converter to underneath my oil pan. I'm hoping this will be ok, my rationale is that the newer TJs had cats right off the header, so this can't be any worse than that. Just trying to get heat away from the floor. If it doesn't work out, it shouldn't be that difficult to cut it out and replace it with a straight pipe.
Here it is installed. I got the pipe off the header tucked in really well so hopefully the driveshaft will clear it better than my factory one.
Next, I wanted to do some testing on muffler placement. First, I just slid some slip joint sections together to simulate an exhaust system, then put the muffler right at the end.
Test 1 audio results:
This was pretty uncomfortably loud actually, really resonated in your ears at idle. Not a fan.
Next test was with the muffler right after the cat, then with the same pieced together exhaust after it.
Test 2 audio results:
This was noticeably more pleasant at idle, but was still too loud. It also had a distinct drone slightly above idle, maybe 1400 rpm or something, I didn't look.
After that, I revved the engine a few times and accidentally blew the whole system onto the ground doing that. To my surprise, though, the audio levels of an open exhaust after the cat was like almost exactly the same. It just sounded "gurglier".
Here is the audio from the open exhaust:
I don't really know what to make of this. I'm not sure if the muffler is literally doing nothing, or if the sound leaking out of the unsealed loose slip joints is invalidating the test. The muffler almost seems like a megaphone though considering the first test was loudest, or that could have just been a temperature thing.
Not sure if I want to proceed as is and hope sealing up each joint will quiet it down, or if I should just look at different mufflers.