Now i have heard that you get more power and a better sound if you either remove the cat or tear out its insides....is this true?
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And your emissions kill kittens 37% faster. -
yea but now your just talking semanticsComment
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In some cases the loss of backpressure will decrease performance.Comment
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ok thanks just curious!Comment
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You'll probably gain a few mpg's, and a few ponies, especially if it is already starting to clog. "Gutted cats" to me don't sound very good, but to each their own. If your state has a visual inspection then you need to have one in place (just in case). If no visual inspection is required I would remove the old cat and keep it (they are worth some $$$ for the platnium), then put something like a magnaflow in its place to act as a resonator.Comment
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Yesterday I pulled the exhaust from my Vanagon and wondered how it ever passed SMOG, 2 pieces oc catalist 1" in diameter fell out, the rest was totally gone
but I finnished up anyway, cut the top off the muffler with the plasma cutter, chopped the insides up, welded 'er up and reinstalled, sounds & drives much better, I'll order a new cat 
This place is like catholic school, 2/3 of the students smoke weed on a daily basis, but the faculty seems to convince the outside world that drugs are just in the other schools, the resident pot dealer thinks he's cool because he has the originality to call anyone he doesn't like a homosexual, and most of the little children follow him like sheep, then there's the few with brains, you hardly ever hear from them, perhaps don't even know they exist, but they get all the sh!t done.Comment
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I pulled my cats and put in a resonator. Much nicer. :)sigpicComment
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best way to go.^^^^^ you can use glass packs, but they will "buzz" when you lift on the throttle (like shifting, coming to a stop, ETC)
gutted cats are very loud. i know, my cam kills them pretty quickly. another reason to eliminate the cat is to keep your BIG assed cam from burning it up until the next time you have to go through emissions/inspections. just make it a bolt-in/out with flanges.
for the most power i would replace the cat with straight pipes, this will keep up the exhaust velocity (negotiable, but a little more than the "expansion chamber" created by the gutted cat).
i noticed a difference in the tune i needed w/o the cat verses with the cat. my mileage, HP, and torque sure seemed to go down with the cat installed (butt dyno for HP and torque). i also started pinging on acceleration until 2500-2800 RPM with the cat installed. i don't see why but it stopped with the cat gone. i do however have a very far from stock motor so a lot of my results wont apply.seien Sie größer, als Sie erscheinen
Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.Comment
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Grassroots motorsports did a cat test a few issues back. I forget what car a decade old miata or civic or something. Factory cat vs OEM cat vs various aftermarket hi-flow cats. They did it all on a dyno with emmisions test equipment The difference between no cat and OE cat was like 3hp max, but the difference in emissions was staggering. The hi flow cats were almost equal too or up to 1.5hp less than the test pipe and had near OEM levels of emmisions output.
IMO the work involved in removing a cat isnt worth the reward.Comment
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My mileage increased by 3 mpg with no cat...I removed mine about 5 years ago when I had some weird driveability problems. If I'm not mistaken, some of the earlier e30's didn't come with cats, just a resonator and a muffler. I'm not certain when e30's started getting converters in europe.Comment
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You will gain almost no peak hp, but drivibality improves and the engine accelerates more easily, as does the vehicle, it is a big legal no-no and I can't recomend it for that reason.
This place is like catholic school, 2/3 of the students smoke weed on a daily basis, but the faculty seems to convince the outside world that drugs are just in the other schools, the resident pot dealer thinks he's cool because he has the originality to call anyone he doesn't like a homosexual, and most of the little children follow him like sheep, then there's the few with brains, you hardly ever hear from them, perhaps don't even know they exist, but they get all the sh!t done.Comment
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