Opinions on hollowed cats?

[hellrot Ofl]

I was planning on hollowing out my catalytic converters because they are clogged. I have a Triflo exhaust and I was wondering if it would change the sound my exhaust makes if I did so.

[northeaste36]

my friend hollowed the cat in his miata and you could definitely hear the difference.he had a stock exhaust with a magnaflow muffler. now sometimes i hear cars go by and i think i can tell that they have hollowed cats.supposedly it can net a few hp depending on the car.

[sweet e36 pimp]

the smart thing is to ditch the cat all together. im going to weld in 2 straight pipes in place of the cat, the weld the empty canister back around the pipe. :lol out of sight, out of mind. this would probably work the best for the obd1 cars, as tampering with the cat would most likely throw a cel on the obd2 cars unless you have o2 simulators. in other words, the "post-cat" sensors will trip the computer.

[hellrot Ofl]

Im not trying to eliminate it because that wont pass inspection but if I have them at least there, then it will pass. I just hope it doesnt sound awful because one of my friends said it might sound bad.

[sweet e36 pimp]

yeah, i was saying to reweld the empty canisters back over the straight pipes, to meet "visual inspection" the cats just being punched out may gain you a few horses, but wont flow as smoothly as straight piping because of added turbulence. thats why doing what i want to do, is a very inexpensive version of a track pipe, that appers street legal. they will also make the ar a tad louder, but i cant see it making it sound bad.

[sweet e36 pimp]

yeah, i was saying to reweld the empty canisters back over the straight pipes, to meet "visual inspection" the cats just being punched out may gain you a few horses, but wont flow as smoothly as straight piping because of added turbulence. thats why doing what i want to do, is a very inexpensive version of a track pipe, that appers street legal. they will also make the car a tad louder, but i cant see it making it sound bad.

[M52 POWER!]

I did this, it's a bitch to gut them, stuff in there is like STEEL honeycomb, not the regular ceramic stuff on most cars that cracks away. Anyways the sound is raspier and the "burbly" noise is a lot louder, I like it not ricey at all.

[sweet e36 pimp]

hey man, what is the diameter of the piping for the mid-pipe? 2"? im too lazy to crawl under there in the rain... if you can let me know id appreciate it. thanks.

[northeaste36]

wouldnt be ideal to have some kind of set-up where you can quickly swap the cat and test pipe back and forth(slip-fit?),cats are expensive,but i guess if its toast anyway...

[mgcook]

i wouldn't do it. the only thing you get out of it, is a louder exhaust, and loss of power...it decreases velocity and backpressure, thus decrease power. it has been dyno proven

i'd just get a cut-out