I thought it would be interesting to share this project with the community.
I originally wanted a GT3 style M&K exhaust for my '86 Carrera, but I enjoy mild fabrication and wanted to try developing something myself. I spent some time on the exhaust clip thread listening to the the different muffler sounds and characteristics and settled on a Magnaflow 1 in 2 out style. I wanted to keep a cat on the car because it is my daily driver but clearly the stock cat was old and too restrictive.
I settled on a design and got to ordering. I ordered a Magnaflow high flow cat (metallic), a 1 in 2 out SS Magnaflow muffler, a 2.5" 304 SS U bend, two 2.5" SS 3 bolt flanges, a SS O2 bung and a 2.5" 321 U bend from Burns Stainless. I later ordered a couple of large band clamps from McMaster-Carr, but not until I had the muffler in place and could measure the strap circumference.
I didn't want to use the stock outlet location combined with the second out on the other side, the center out (GT3 style) didn't naturally make sense because of the muffler style so I came up with the idea of going through the bumper (Carrera GT style). Lots of turbo track cars have holes drilled in the bumper but I haven't seen any done with the exhaust exit there. This orientation uses very little tubing after the cat. The whole setup is also very light compared to the stock cat and muffler.
I was a bit nervous that I would be cutting up a perfectly good bumper and ending up disappointed, but it turned out nicely. There is plenty of room in there for the muffler, the muffler body is angled so that the tips come out level with the openings, the straps fit around the factory brackets and it is all tucked up nicely with nothing hanging below the valance. I had to get a set of euro bumperettes (darn), and then fabricate the trim rings for the opening. I put some aluminum mesh in the trim grills to make it all look clean and tidy, and got a full valance from RarelyL8 that fills in the stock outlet. I need to trim the driver's side lower bumper end, paint the new valance and bumper ends to finish the project.
I am happy with how it turned out, it looks good, sounds good, and power is up as well. It is not as loud as I thought it would be, and it is plenty quiet for a daily driver. The sound is deep down low and mean up top. It also has a nice deceleration burble that really sounds nice. I'll take some better pictures of the whole car and some underbody shots if anyone is interested in how it all looks underneath.
Cheers,
Chad
