Another busy weekend in the shop fixing broken stuff and finishing things the right way. Seems like I had to work on almost everything with wheels and a battery. Without A/C I would just complain and procrastinate until cooler weather.
Decided to change mufflers again on my cobra. For last 5 years I have had Magnaflow 14"x4" round (aka magnapak) mufflers in Bolra tubing. Like the Bolra stinger mufflers (5"x10"), the round MF did little muffling and were loud as F in all conditions. The only aspect I didn't really like was the blatty sound at high load/low rpm. Raspy would be the word flatbillers would use, bro.
So it was time for change. I bought the largest case (oval 14x9x4) straight through mufflers that would fit to quiet things down. MF makes a cat back with these, but I'm cheap and have a welder. The cobra's IRS needs a offset/offset on the same side so this narrows muffler possibilities down a lot. MF had this muffler available only in polished for extra $30. The polish is done before the mufflers are welded so half-assed, really. I was concerned that since the perforated internal tube was so close to one side of the case they wouldn't attenuate well and may be too similar to the round. The perforated tube actually makes a curve to get it away from the wall, and results are quiet different.
I like the adjustability of the Bolra tubing, but the original design put the short muffler in an odd place. I adapted the longer magnapaks in as best I could and tig welded them myself (1st attempt at tig welding). To get the new oval muffs centered in the floor pan cavity, I bought a length of SS pipe to add as needed.
Left side mocked up. Only needed a small wedge to connect the tailpipe.
Once adjusted so all hangers were neutral, the right side tail pipe was hitting the diff brace so I hit it with the grinder until it cleared.
I was not able to find 309 mig/tig locally so I ended up getting a roll of ER308L mig wire and used with C25, at 110V, on autoset (yes, I broke all the rules). It welds for me just like mild steel, fast and ugly. I tacked on the car and finish welded on the bench.
I refrained from grinding all the welds and polishing the tubing. I had previously polished the tail pipes, but didn't have half a day to spend turd polishing. No one ever sees the bottom of the car, except for all of you.
So, how does it sound?
Idle: little quieter

part throttle cruise: much quieter, drone is gone

Low rpm/high load: rasp is gone

WOT: similar, LOUD
