March 4, 200521 yr i looked before the 2nd cat in my car and the exhaust narrows to 1.5" before the 2nd cat. why did they design it so?
March 4, 200521 yr low end torque! that and they never thought that heat shield would rust away. so when it was new, it looked like it had some desent sized exhuast.
March 4, 200521 yr Author low end torque! that and they never thought that heat shield would rust away. so when it was new, it looked like it had some desent sized exhuast. heat sheild? you mean on the 2nd cat? its not rusty on my car. but like everyone says scavaging does not improve by making the exhaust smaller.
March 13, 200521 yr Author i was thinking of taking a tailpipe expander to the area. can anyone think of any reason I shouldnt?
March 13, 200521 yr I haven't looked at it, but I can't think of a good reason other than fitment issues. No exhaust "tuning" is effective after the first major obstruction to exhaust flow. Mufflers and cats attenuate any exhaust pressure pulses, so no further benefit can be derived by keeping the atmosphere side restrictive.
March 17, 200521 yr I think the pipe ahead of that point is about the same size, so I don’t think there is much to be gained by expanding it at that point. If the pipe forward looks larger check to see if its double wall. My ’87 GL wagons is, looks big on the outside but its only about 1.5" inside the inner pipe. Its like that from the heads to the muffler and I’m sure its stock. I found it when I had a bad rattle in the mid pipe, I fixed it with a few spot welds from the outer to the inner along the pipe, I did the Y-pipe too. Gary
March 18, 200521 yr '87 GL wagon,D/R: So Gary--the rattle on idle and during deceleration that I have been thinking is in the inside of the cat may be something else rattling? Sure hope so, cheapest new cat I can find is $180+. Ray Mac
March 18, 200521 yr '87 GL wagon,D/R:So Gary--the rattle on idle and during deceleration that I have been thinking is in the inside of the cat may be something else rattling? Sure hope so, cheapest new cat I can find is $180+. Ray Mac My '87 had the same idle/decel rattle, I read some people fixed loose cat "bricks" by squeezing the can, I tried this with no success. So I pulled the mid pipe and found it was the inner pipe, so I cranked up the welder and burned through the outter to the inner in about dozen places, and not a sound since. Gary
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