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gutting out the catalytic converter

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Old Jun 18, 2007 | 08:50 AM
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gutting out the catalytic converter

alright...about a month ago i bought a 94 z28...everything on it is stock...i plan on buying a flowmaster muffler very soon...but there is one thing i want to do before i put on a muffler, and that is to gut out the cat, because i want it to be loud. As you know the catalytic converter is pretty much a box sitting up under the camaro..and on my old v6 i took it off one time and looked at it and it had been gutted out because it was quite loud for a 6 cylinder...so what i want to know is...does the converter have chemicals in it that makes it so quiet? or can you simply use a coat hanger and gut it out? from what everyone has been telling me?
Old Jun 18, 2007 | 10:27 AM
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???
Old Jun 18, 2007 | 12:56 PM
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There is an actual physical catalyst inside, it can be knocked out.
Old Jun 18, 2007 | 01:32 PM
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thanks alot man...i did see the catalyst...it's like a honeycomb looking thing...i chipped some of it out but i would like to do it without it falling out inside the cat....i cant fully take if off because part of the cat is welded to the pipe which isnt good
Old Jun 18, 2007 | 06:08 PM
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The ol' gutted cat and Flowmaster combo. To be young again.
Old Jun 18, 2007 | 08:30 PM
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Gutting the cat causes funky air velocities that do not help to increase power and actually make the exhaust sound bad. Pull the cat and install a bullet muffler.
Old Jun 19, 2007 | 11:41 AM
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mine are gutted w/ a stock manifolds to magnaflow catback w/ 3" cutout. Sounds wicked w/ the 3" cutout just idling, especially when I first start it up. W/ the m6 its real fun to drive you can control the amount of noise you want to make.
Old Jun 19, 2007 | 11:59 AM
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why not just take it off and have someone put a piece of pipe in its place, when i first got my car i had my cat gutted, a month later i had it removed because it sounded terrible

Last edited by davidz28guy; Jun 19, 2007 at 12:01 PM.
Old Jun 19, 2007 | 01:25 PM
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If you want your cat gone that bad, put a piece of straight pipe in its place. By simply gutting it, the air velocities get screwed up as the exhaust passes through what is now a big open chamber and tries to find its way out the other side.

Straight pipe in place of the cat will give it more volume without hurting anything else. However, there isn't a HUGE gain to be had by gutting it, simply for sound.
Old Jun 19, 2007 | 01:57 PM
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yea a friend of mine did mention putting a straight pipe on...the thing is, is that the pipe is welded at the front of the cat leading up to the engine which means ill have to cut it off...i just dont want the chance of messing it up and having to weld it back together
Old Jun 19, 2007 | 10:32 PM
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come on now, there is going to be some gain by gutting the cat vs. not. Obviously, despite the air getting moved around. I'd say its good for a couple hp at the top end.
Old Jun 20, 2007 | 06:50 AM
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Originally Posted by Jazsun
come on now, there is going to be some gain by gutting the cat vs. not. Obviously, despite the air getting moved around. I'd say its good for a couple hp at the top end.
not really, with a intact cat the air at least flows where it is supposed to, once it is gutted the exhaust flows into a empty chamber where it bounces all over the place trying to find its way out, but either way theres probaby not much of a difference in performance

Last edited by davidz28guy; Jun 20, 2007 at 06:53 AM.
Old Jun 20, 2007 | 08:06 AM
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needless to say I didn't gut mine a previous owner did. I personally would not take the time to do it, rather get an offroad y pipe. But since it was done already, I can't complain.
Old Jun 20, 2007 | 08:26 AM
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the thing is...i'm not even looking to do this for performance...i just want it louder...i like the raspy sound personally...i'll move to performance later on down the road...i plan to keep this car a long time and im actually considering turning it into a drag car later in the future
Old Jun 20, 2007 | 09:18 AM
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Originally Posted by davidz28guy
not really, with a intact cat the air at least flows where it is supposed to, once it is gutted the exhaust flows into a empty chamber where it bounces all over the place trying to find its way out, but either way theres probaby not much of a difference in performance
If a cutted cat hurts velocity, then I imagine a closed cut-out would to the same. A 3" wye with a cap on the branch is going to cause some disruption then too. (My theory)



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