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Discussion Starter · #1 ·
How to build your own exhaust when you don't much of anything about fabrication work:

Tools / Materials needed -
  • Wrench / sockets for exhaust bolts on header / downpipe / whatever it is you have,
  • Man-hands for rubber hangar removal,
  • Jack,
  • Jackstands,
  • MIG / TIG welder, I used my 140A Hobart MIG with a 75/25 mixed bottle.
  • Welding gear to keep sparks off you, and your eyes working.
  • Wire cutter for welding wire trimming.
  • Wire brush for cleaning welds.
  • Wire wheel attachment for cut off wheel for cleaning material before / during welding.
  • Hack saw.
  • Sawz-All / Reciprocating saw.
  • Flat and rounded metal files to clean up edges on cuts.
  • Any other oddball metal cutting tools you might want to use, examples: chop saw, radial arm saw, etc.
  • Impact socket driven pipe expander, for slip fit connections.
  • High temp rust proof / resistant paint, rattle cans are fine, so is brush on hotness.
  • Exhaust components, whatever you want to run. I suggest Online performance and OE car parts site - Home This page of theirs is also helpful Discounts

Things I didn't show -
  • Jacking up the car.
  • Removing the old exhaust.
  • Painting the new exhaust.
  • Ground clearance pic, see my build thread?
  • Audio / Video clip of the exhaust sound, but desired sound will vary with personal preference.

That said, on with the show -

Take what ever you're going to start with; in this case the cat, and bolt it up to the car.

*NOTE* you will remove the exhaust as you're building it a bunch with my method. I think this exhaust was in and out 6-8 times before I was finished with it.
*NOTE* It is also CRITICAL that you clean the metal before and after any welding, for both safety and work quality reasons.

Take a look at it and think about where you want the pipe to go after the cat. In this case I cut down a 45 degree mandrel bend, butt welded a straight section to that, and then used a slip fit joint over the cat to help me have enough leeway to avoid hitting anything on the car.

Then you either tack that to the previous part of the exhaust you're building off of. Or you can mark it with a sharpie in a very careful and precise manor so that you can tack it in the EXACT same orientation as it was on the car.

Did not take pictures of that process, but after you weld it up... I wound up with this:

Welded up

On the car

Welds aren't the best, but I think this is my first legit welding project for myself. And still a couple times better than the exhaust shops locally who would charge a ton for doing this and give you even worse welds.

Moving on....

After that I needed a straight section, so I cut one out of a pre-bent section on my radial arm saw, tacked it in place using a magnet to help hold it in place.

When tacking its important to keep as much space between your last tack and your next one as possible. I try to do about 8 or so tacks, and wind up doing them the same as you would torque an 8 lug wheel in a star pattern.

Once the tacks are in place, wire brush / otherwise clean the shit out of it so that the galvanized coating is gone / any slag left over from the tacks. Clean metal welds better, and the gasses from welding galvanized material and from certain cleaning products (carb cleaner / brake cleaner) are nasty dangerous (and potentially lethal) vapors that I don't want to mess with.

Close up of another but welded joint after being tacked and wire brushed clean.

After welding.

Gets us to the back of the subframe when its back in the car. But now it needs help being supported.

Then you bisect another mandrel bend by hand, only this time I decided to add a small section of slip fit pipe to it to speed things up a bit. Weld small bit of pipe to small bent bit of pipe, weld the now slightly larger small bent pipe to the rest of the exhaust. Now I made sure the small bent pipe was also long enough to bridge the gap between the muffler and turn down and the rest f the exhaust. But I digress. It looks like this when you're done this step.

Then you align the muffler can to marks / tacks you made when the exhaust was last on the car.

Finish welding the muffler on, add some hangars, and BAM. Finished project.

Up in the car, hangs down a bit more than I'd have liked but I may be able to fix that... and it was 4am, and I just wanted to get the bitch done.

After this, apply rust proofing / other high temp paint to DOUBLE the life of the exhaust. When using mild steel on roads that get salted, plan for 1-3 years of life before it rusts out without paint, and 3-5 years with painting it.
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