X-Pipe (With or Without High Flow Cats)
Thread Starter
Racer
Joined: Aug 2007
Posts: 251
Likes: 0
From: Parkland Florida
X-Pipe (With or Without High Flow Cats)
What would you rater have, and X-Pipe with High Flow Cats or an X-pipe with out cats? Whats the difference between the two i nreference to performance and also sound quality?
Thanks in advance for all advice!
Thanks in advance for all advice!
Le Mans Master
Joined: Oct 2007
Posts: 6,149
Likes: 11
From: Greater Detroit Metro MI, when I'm not travelling.
Both are illegal (you can not replace catalytic converters on a car that is less than 10 years old), but the catless one will be a lot louder and definitely fail emissions tests, whereas a catted exhaust can be tuned to pass sniffer. Going catless will offer some performance advantage; a few HP on a stock-ish car, and a few dozen HP on a highly modified one running forced induction.
My personal preference is to run catted because of the reduced noise and the fact that it at least won't smell so obviously illegal
My personal preference is to run catted because of the reduced noise and the fact that it at least won't smell so obviously illegal
Burning Brakes
Joined: Jun 2007
Posts: 878
Likes: 145
From: Little Egypt, USA
ANY change to the stock exhaust system from the cats forward is illegal, even to remove a working stock cat and replace it with a new one in the exact same place. 
So I decided why restrict the flow more and and pay more money for cats when you would be illegal either way. Yes some say it's only 5hp difference but I want all of it I can get. Cats may also add more heat to the tunnel than with out. HF cats are supposed to pass the sniff test but one look at the car will do you in anyway. I think most states do or will be including a visual inspection as part of the test.
Its an individual choice for every one to make and I am lucky to live where they don't test at all. After all the warnings on the forum I expected the smell to be terrible but it isn't. No where close to the cars I owned in the pre cat days but then I was never bothered by them. I think a car that is not running overly rich won't cause a high performance enthusiast to regret no cats. That is of course my humble opinion.
The sound with headers, no cats and the stock mufflers is perfect for me. No drone but yet a strong muscle car sound when the go pedal is mashed.
So I decided why restrict the flow more and and pay more money for cats when you would be illegal either way. Yes some say it's only 5hp difference but I want all of it I can get. Cats may also add more heat to the tunnel than with out. HF cats are supposed to pass the sniff test but one look at the car will do you in anyway. I think most states do or will be including a visual inspection as part of the test.
Its an individual choice for every one to make and I am lucky to live where they don't test at all. After all the warnings on the forum I expected the smell to be terrible but it isn't. No where close to the cars I owned in the pre cat days but then I was never bothered by them. I think a car that is not running overly rich won't cause a high performance enthusiast to regret no cats. That is of course my humble opinion.
The sound with headers, no cats and the stock mufflers is perfect for me. No drone but yet a strong muscle car sound when the go pedal is mashed.
Last edited by wbear; Jan 8, 2008 at 02:43 PM.
Le Mans Master
Joined: Oct 1999
Posts: 8,205
Likes: 40
From: Tucson AZ
Both are illegal (you can not replace catalytic converters on a car that is less than 10 years old), but the catless one will be a lot louder and definitely fail emissions tests, whereas a catted exhaust can be tuned to pass sniffer. Going catless will offer some performance advantage; a few HP on a stock-ish car, and a few dozen HP on a highly modified one running forced induction.
My personal preference is to run catted because of the reduced noise and the fact that it at least won't smell so obviously illegal
My personal preference is to run catted because of the reduced noise and the fact that it at least won't smell so obviously illegal
Pro
Joined: Mar 2006
Posts: 658
Likes: 0
From: Pa
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