Gutted cats vs. no cats???
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 5,404
Likes: 45
From: Arlington Tx
St. Jude Donor '08
Gutted cats vs. no cats???
I have a "friend" who has eliminated the cats from his '92. I'm pretty sure that this will flow better than a hollowed out cat, but how much? there is a spare set of pipes with legit cats around here.. should "he" hollow them out and run them all the time, or leave them alone and install them just for state inspection?? :blueangel:
Drifting
Joined: Apr 2002
Posts: 1,451
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From: Owensboro Ky
Re: Gutted cats vs. no cats??? (qblue92)
If "he" has to go through inspection I would put the gutted cats on. Gutted cats can't cut the flow that much, and it has to be better than keeping the cats on or changing them every year before the inspection. But thats just my opinion. :cheers:
Le Mans Master
Joined: Mar 2001
Posts: 8,471
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From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
Re: Gutted cats vs. no cats???
Replcaing the cats with a straight pipe would be the best solution. Leaving the gutted cats there will cause turbulence in the airflow path and will also often cause sound issues that can include rattling (if there is anything left inside) and resonance. Trust me on this, I had a "friend" that did the gutted route on his LT1 Formula and wished that he had replaced it completely or left it alone.
Racer
Joined: May 2001
Posts: 320
Likes: 0
From: TX
Re: Gutted cats vs. no cats??? (corvette0096)
If your friend needs cats for emissions visual inspection. He might want to take a cat, cut it in half and reweld it on a straight pipe. Although the nice thing about vettes is that you can't see under the car unless it is on a lift.. :D
I have heard that the high flow cats don't hurt power that much if you have emissions testing in your state.
I have heard that the high flow cats don't hurt power that much if you have emissions testing in your state.
Race Director
Joined: Jul 2001
Posts: 14,604
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From: Glendale, AZ
Re: Gutted cats vs. no cats??? (EvanLT1)
i hollowed mine out last week and have noticed a considerable improvement in performance! as far as rattling and noise, the only noise i now hear is the sound of the L98 breathing like she was meant to breathe!
in Az, you need to go through inspection only every 2 years, so i will eventually remove the pipe and replace every 2 years with a legit cat just for inspection! :cheers:
in Az, you need to go through inspection only every 2 years, so i will eventually remove the pipe and replace every 2 years with a legit cat just for inspection! :cheers:
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Re: Gutted cats vs. no cats??? (Skippy Stone)
Are we talking removing everything from the cats or just the screens?
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Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Re: Gutted cats vs. no cats??? (corvette0096)
I would just gut them and put a straight pipe thru it, so you can have them for visual inspections. If you just gut it w/o puttin a pipe in, youll prolly have resonance problems.
Racer
Joined: Jul 2002
Posts: 401
Likes: 1
From: Aptos CA
Re: Gutted cats vs. no cats??? (vader86)
removing all the internal stuff..
[/QUOTE]I would just gut them and put a straight pipe thru it, so you can have them for visual inspections. If you just gut it w/o puttin a pipe in, youll prolly have resonance problems.[/QUOTE]
Good idea.
Drifting
Joined: Jul 2001
Posts: 1,751
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From: Miami, FL, USA
Re: Gutted cats vs. no cats??? (snake killer)
I cut them out and put straight pipes on all 3 cats- great improvement, but VERY LOUD and the resonance is deafening. I now am considering a Power Effects system or putting a high flow cat.
Racer
Joined: Jul 2002
Posts: 401
Likes: 1
From: Aptos CA
Re: Gutted cats vs. no cats??? (snake killer)
If you gut them won't you have O2 sensor problems? Don't you need those o2 readings in order for the computer to determine the fuel/air mixture?
Keep killin' those snake! :smash:
[Modified by Skippy Stone, 5:11 PM 7/5/2002]
Race Director
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From: Troll Free Zone
CI 4-5-6-7-8-9-10-11 Vet
St. Jude Donor '06-'07-'08-'09
Re: Gutted cats vs. no cats??? (qblue92)
I understand a straight pipe through the cat shell would satisfy a visual inspection, but wouldn't fool the sniffer probe we have here. :mad
