2004 Catalytic converters
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Formerly "ZCHPRO"
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From: Chandler
2004 Catalytic converters
Quick question about the four cats on my year's truck.
I know that the first two are the typical DO NOT REMOVE under penalty of law kind of cats. But are the back two some kind of other cat? Someone told me that there was a possibility that they were "resonator cats" and that if they were I would be able to take them off legally.
does anyone know if this is true?
can someone tell me if there's even a difference between the front cats and the rear cats on my truck?
basically I just want my exhaust to sound better like this guy (same year and body style)
So in a nutshell I just want to know if they are different, if its illegal to remove the rear two, if I have to worry about any sensors if I do this, and if it will help performance at all (rumor on one of the sites I was browsing said a dyno chart had 20+ hp from removing them but I'm not prone to believe this, just curious)
any and all help is always appreciated.
ps I know it will take more than just cats to get my truck to sound as good as the one in the video, just thought it would be easier to do the cat removal first (or at the same time).
I know that the first two are the typical DO NOT REMOVE under penalty of law kind of cats. But are the back two some kind of other cat? Someone told me that there was a possibility that they were "resonator cats" and that if they were I would be able to take them off legally.
does anyone know if this is true?
can someone tell me if there's even a difference between the front cats and the rear cats on my truck?
basically I just want my exhaust to sound better like this guy (same year and body style)
So in a nutshell I just want to know if they are different, if its illegal to remove the rear two, if I have to worry about any sensors if I do this, and if it will help performance at all (rumor on one of the sites I was browsing said a dyno chart had 20+ hp from removing them but I'm not prone to believe this, just curious)
any and all help is always appreciated.
ps I know it will take more than just cats to get my truck to sound as good as the one in the video, just thought it would be easier to do the cat removal first (or at the same time).
Thread Starter
Formerly "ZCHPRO"
Joined: Jul 2010
Posts: 1,950
Likes: 36
From: Chandler
oh
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The rears on the 04-05 trucks do have a catalytic function. That's why when you remove the rears the O2 light pops up. The 97-03 guys can get away with it because the rears on those are mainly resonators and do little conversion.
"Legally" none of them can be touched. If you want more sound and stay legal, replace the rear two with hi flows.
Unless you're doing headers too, removing the cats alone won't create a real power gain.
"Legally" none of them can be touched. If you want more sound and stay legal, replace the rear two with hi flows.
Unless you're doing headers too, removing the cats alone won't create a real power gain.
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From: Lake Mary Florida
On the early Fords, they used 4; and for the record, the law applys to all of them, not just the fronts. In other words, the feds say whatever your truck came with in the way of emisions, must remain.
It may be possible that you can remove all 4 and replace with two certified high flow cats. That would be a question for the "legal" muffler shops to address.
It may be possible that you can remove all 4 and replace with two certified high flow cats. That would be a question for the "legal" muffler shops to address.