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post #1 of (permalink) Old 01-30-2003, 05:04 PM
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Guttin the cat converter

hey guys,
I was wondering if yall could give me some advice on this. I want to get a better sound out of my exhaust and since my truck has 2 cat converters would it make much difference if I gut one of them? or just simply take one off and just add a piece of pipe in its place. I don't have emmisions in my county yet, but if I ever get emmisions test would it still pass with just one cat converter? Also would this even be worth my time doing, would it even improve the sound enough? and if so would it be better to gut one or just simply remove one? I like to think I know a good amount about working on trucks but I know a ton of you guys know WAY more than i do. And yall really help out alot answering some of my questions. [img]images/graemlins/givemebeer.gif[/img]
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post #2 of (permalink) Old 01-30-2003, 05:19 PM
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Re: Guttin the cat converter

I cut the muffler off and ran a pipe out the side. I still have the cats and itsound pretty damn good. The whole "system" cost me like $17 and about 1/2 hour. Freed up a little power and the cops keep eating their dougnuts when i pass cuz they're looking for a Mustang or Camaro. I guess they think all older trucks sound loud. If i do get pulled over i can just say i dont have the $$ for a new exhaust so i had to do it cuz i dont want my kids dying of Carbon Monoxide while driving with the pipe spewing under the cab. Can't remember the sizes of any of the pipes but just test fit them before you leave the store and make sure you know the O.D. of the pipe coming off the last cat. Build it from there. I had mine come outside the frame rails as soon as they arch upwards. On a Bronco thats in a differnet spot then the pickups so make sure you get enough pipe.

Plus gutted cats sound kinda funny. Almost hollow like you're using a 5" pipe on a 4CYL 120HP rusted out 79 nissan or something. Not a ricer sound, doesn't have that crisp raspy tone just hollow.
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post #3 of (permalink) Old 01-30-2003, 06:47 PM
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Re: Guttin the cat converter

when you gut the cats jsut insert some exhaust pipe or water pipe on the sinide of it and weld it in so it doesnt create a expansion chamber(gives it that hollow sound and makes a power loss), i found a steel rod guts them nicely.
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post #4 of (permalink) Old 01-30-2003, 10:29 PM
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Re: Guttin the cat converter

i did this to my second cat and it helped power a ton, mainly because the 10 year old cat was spent from what i could tell. my first cat wont pass any light through, so i'm guessing it needs to go also, but it's harder to get to. i liked how mine sounded with it gutted and no tail pipe, but with a massively leaky manifold anything will entertain me [img]images/graemlins/wink.gif[/img] The best bet would be to have a new system drafted from the manifolds back, and dont ask what to do because there were several thorough threads on this in the last couple weeks. Read them and you do what they say and you'd be surprised. Thats my plan, I dont like how the pipe rides the tranny anyway, and I'm sure I can do way better than factory as far as sound and performance.
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post #5 of (permalink) Old 01-31-2003, 09:54 AM
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Re: Guttin the cat converter

For the past 3+ years I've run with no muffler and only the stock cats. It's quiet. The cats are that restrictive, or at least muffle sound that well. I just removed my rear most one and could see a pin-hole of light thru it. I'll replace it with a hi-flow unit. I started it for a few seconds without the second cat, and it certainly rumbled much more.
post #6 of (permalink) Old 01-31-2003, 10:58 AM
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Re: Guttin the cat converter

I'll second, ... um third - fourth ... anyway ... I too am running 2 cats w/ no muffler on the big 6 ... it sounds great! (or is that my exhaust leak?)

I am also considering gutting the cats when I swap in the 351 (might be this-coming week!), I figured I'd pound 'em w/ my 4lb sledge & shake the sh*t out of em, but a chunk o' rebar sounds like a good alternative, too.

Oh yeah ... </font><blockquote><font class="small">In reply to:</font><hr />
if I ever get emmisions test would it still pass with just one cat converter?

[/ QUOTE ]
I doubt it, each cat takes a different combination of noxious sh*t out of the exhaust gasses, I'd think both are required.
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