High flow catalytic converters
Thread Starter
Instructor
Joined: May 2004
Posts: 100
Likes: 1
From: Bristol Tennessee
High flow catalytic converters
I recently bought a couple of high flow catalytic converters for my C5. Took them to a local muffler shop to have them installed. The owner of the shop said if he replaced them the check engine light would probably stay on and he also said the small converters from the factory were high flow anyway. Is this true or do I have a shop that just didn't want to change them ? Second if I change them will check engine light stay on? It looked to me the sensors would be behind the converters. 
Last edited by rickw99vette; Jan 18, 2015 at 10:22 PM.
Drifting
Joined: Jan 2012
Posts: 1,341
Likes: 8
From: Hopatcong New Jersey
Unless you had a problem with the factory cats, there is really no reason to install high flow cats. Just a waste of money in my opinion.
The rear O2 sensors just tell the computer whether or not the cats are functioning. Some of the cheaper aftermarket high flow cats cause a check engine light, some don't. You can have the rear O2 sensors tuned out if you get a light.
The rear O2 sensors just tell the computer whether or not the cats are functioning. Some of the cheaper aftermarket high flow cats cause a check engine light, some don't. You can have the rear O2 sensors tuned out if you get a light.
Thread Starter
Instructor
Joined: May 2004
Posts: 100
Likes: 1
From: Bristol Tennessee
Unless you had a problem with the factory cats, there is really no reason to install high flow cats. Just a waste of money in my opinion.
The rear O2 sensors just tell the computer whether or not the cats are functioning. Some of the cheaper aftermarket high flow cats cause a check engine light, some don't. You can have the rear O2 sensors tuned out if you get a light.
The rear O2 sensors just tell the computer whether or not the cats are functioning. Some of the cheaper aftermarket high flow cats cause a check engine light, some don't. You can have the rear O2 sensors tuned out if you get a light.
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
Everything I've read indicates the stock converters will not be a bottleneck, even with headers and loads of power. That said I'm installing headers right now and if I run cats (haven't decided 100% yet but my conscience is telling me to), I will replace mine with new "hi-flow" units as one of mine is discolored (indicating an issue). And I was getting a code on that same side before I pulled the car for the winter.
Thread Starter
Instructor
Joined: May 2004
Posts: 100
Likes: 1
From: Bristol Tennessee
Everything I've read indicates the stock converters will not be a bottleneck, even with headers and loads of power. That said I'm installing headers right now and if I run cats (haven't decided 100% yet but my conscience is telling me to), I will replace mine with new "hi-flow" units as one of mine is discolored (indicating an issue). And I was getting a code on that same side before I pulled the car for the winter.
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
Had, no, heard tons about, yep. There is only one reason I would consider not running cats; $. But I'll probably do the right thing. No checks of any sort in this part of Canada, it's a conscience thing only.
Acct Suspended APR 2026 by request
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2020 Corvette of the Year Finalist (performance mods)
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or if you go forced induction... those cars tend to run on the rich side and can burn the cats out... personally I don't mind the smell and like the sound increase
Drifting
Joined: Mar 2000
Posts: 1,956
Likes: 135
From: Maryland
Really????? On my 2000 removing the cats (all four) barely changed the volume. It made the tone a little deeper but not much louder. Sounded more like I would have expected from the factory.
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Le Mans Master
Joined: Sep 2014
Posts: 5,278
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From: Kelowna BC
Instructor
Joined: Dec 2012
Posts: 229
Likes: 2
From: Charleston South Carolina
only way you should get fumes in car is if the tail pipes are not clearing properly to pull fumes behind car or you got a leak after the headers somewhere......cat should not influence that one bit...faulty install or removal can though.
Le Mans Master
Joined: Mar 1999
Posts: 6,029
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From: Palm Coast, FL
Everything I've read indicates the stock converters will not be a bottleneck, even with headers and loads of power. That said I'm installing headers right now and if I run cats (haven't decided 100% yet but my conscience is telling me to), I will replace mine with new "hi-flow" units as one of mine is discolored (indicating an issue). And I was getting a code on that same side before I pulled the car for the winter.
It is LOUD
