C5 High flow cats.
Thread Starter
Team Owner
Joined: Feb 2005
Posts: 35,976
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From: San Clemente California
C5 High flow cats.
What's better to install high flow cats or remove them altogether?
How loud will it get if you remove them. Running Borla Stingers with X pipe at the moment? Will it get crazy loud?
How loud will it get if you remove them. Running Borla Stingers with X pipe at the moment? Will it get crazy loud?
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Joined: Mar 2006
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Here in Vancouver we have to do a bi-annual vehicle emission test that requires you to have cats. That's why I'd stick with the high flow cats just so I don't have to put my cats on just for the test and remove them after. But, if you don't have any test like that wherever you're at, I'd just take the cats right off. It would probably produce better flow.
Thread Starter
Team Owner
Joined: Feb 2005
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From: San Clemente California
Originally Posted by sunnyvette
Here in Vancouver we have to do a bi-annual vehicle emission test that requires you to have cats. That's why I'd stick with the high flow cats just so I don't have to put my cats on just for the test and remove them after. But, if you don't have any test like that wherever you're at, I'd just take the cats right off. It would probably produce better flow.
No tests here, I'm just worried about codes and the noise factor.
Burning Brakes
Joined: Feb 2004
Posts: 831
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From: Poland oh
Mine are out, have LT's - xpipe - corsas. Sure its loud. Not unbearable but everyone knows its not stock. I like the sound. Can't comment what it would be like if I had the Cats for an A-B comparison.
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Joined: Mar 2006
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I have a friend with a stang-no cats. It sounds pretty cool. You can hear it rumbling down the block so yeah, if noise is an issue then maybe get an exhaust system that isn't so noisy. It does sound really cool though.
I don't know what you mean by codes (rookie). Sorry.
I don't know what you mean by codes (rookie). Sorry.
Thread Starter
Team Owner
Joined: Feb 2005
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From: San Clemente California
Originally Posted by ivandrea
Mine are out, have LT's - xpipe - corsas. Sure its loud. Not unbearable but everyone knows its not stock. I like the sound. Can't comment what it would be like if I had the Cats for an A-B comparison.
I don't have LT's yet should I wait to install those or should I go ahead and pull the cats now? What about sensors? Do the cats have sensors that will throw codes if I remove em?
Drifting
Joined: Apr 2004
Posts: 1,530
Likes: 250
From: CT
You'll need to install 02 sims in your rear 02 sensors or have them blocked by a tuner with LS1 edit or HP tuners.
It will get slightly louder with the stock exhaust manifolds but I don't think a significant amount. With LTs it will be quite a bit louder, at least thats what happened in my case with LG Pros/corsa indys. I wouldn't bother removing them unless you are going to install headers, you won't gain much with the stock manifolds.
If you do remove them be prepared for some fuel odor in the exhaust. I actually like it but some don't care for the smell.
Just my .02. Hope this helps.
It will get slightly louder with the stock exhaust manifolds but I don't think a significant amount. With LTs it will be quite a bit louder, at least thats what happened in my case with LG Pros/corsa indys. I wouldn't bother removing them unless you are going to install headers, you won't gain much with the stock manifolds.
If you do remove them be prepared for some fuel odor in the exhaust. I actually like it but some don't care for the smell.
Just my .02. Hope this helps.
Thread Starter
Team Owner
Joined: Feb 2005
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From: San Clemente California
Originally Posted by HRDTOPC54FUN
You'll need to install 02 sims in your rear 02 sensors or have them blocked by a tuner with LS1 edit or HP tuners.
It will get slightly louder with the stock exhaust manifolds but I don't think a significant amount. With LTs it will be quite a bit louder, at least thats what happened in my case with LG Pros/corsa indys. I wouldn't bother removing them unless you are going to install headers, you won't gain much with the stock manifolds.
If you do remove them be prepared for some fuel odor in the exhaust. I actually like it but some don't care for the smell.
Just my .02. Hope this helps.
It will get slightly louder with the stock exhaust manifolds but I don't think a significant amount. With LTs it will be quite a bit louder, at least thats what happened in my case with LG Pros/corsa indys. I wouldn't bother removing them unless you are going to install headers, you won't gain much with the stock manifolds.
If you do remove them be prepared for some fuel odor in the exhaust. I actually like it but some don't care for the smell.
Just my .02. Hope this helps.
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Race Director
Joined: Jun 2004
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From: Schaumburg IL
CI 7-8-9-11 Veteran
St. Jude Donor '06-'10, '13
I put hi-flow cats on..I have ridden in a few cars and did not like the smell without the cats, esepcially on cold start ups.. not saying every car does this, but the few I rode in without cats smelled a bit.
They key to loud is having headers, and a loud cat-back system.
They key to loud is having headers, and a loud cat-back system.
Race Director
Joined: Jun 2004
Posts: 19,459
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From: Schaumburg IL
CI 7-8-9-11 Veteran
St. Jude Donor '06-'10, '13
Originally Posted by DJN
I don't have LT's yet should I wait to install those or should I go ahead and pull the cats now? What about sensors? Do the cats have sensors that will throw codes if I remove em?
if you pull your cats you will throw codes as this effects the O2 sensors, front and rear.. if your state has emissions, you will probably fail, dependig on what type of emissions, but in FL I don't think you have to pass with emissions anyway.Just FYI also, hi-flow cats will probably, key word probably cause your computer to throw codes also, Low Bank Efficency code will pop up since the hi-flow cats don't heat up enough and burn enough exhaust like the stock 02's are programmed for. You can get this fixed with LS1 edit by just turning the 02's off, or buying 02 Sims
Last edited by FrankTank; Mar 14, 2006 at 05:37 PM.
Pro
Joined: Nov 2003
Posts: 532
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From: herminston oregon
HPC coating
Originally Posted by FrankTank
if you pull your cats you will throw codes as this effects the O2 sensors, front and rear.. if your state has emissions, you will probably fail, dependig on what type of emissions, but in FL I don't think you have to pass with emissions anyway.Just FYI also, hi-flow cats will probably, key word probably cause your computer to throw codes also, Low Bank Efficency code will pop up since the hi-flow cats don't heat up enough and burn enough exhaust like the stock 02's are programmed for. You can get this fixed with LS1 edit by just turning the 02's off, or buying 02 Sims
Melting Slicks
Joined: Mar 2003
Posts: 2,744
Likes: 9
From: FL
Cruise-In VI Veteran
Originally Posted by myblackC5
do you think HPC coating the cats would help?
I agree
with FrankTank.
