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Discussion Starter #1
Before you say "oh here we go again someone looking for a muffler", my question has to do with the cats. I am wondering if I should delete the first cat, second, or both when I install my muffler? I have 3.7L and have seen several of the threads discussing deleting the cats but nothing regarding which is best for possible gains. I wasn't sure if it just all depended on how I wanted the truck to sound or if there was reason to delete one over the other or both. Thanks for any and all input.
 

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I thought deleting cats was against Federal law, no?
 

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Discussion Starter #3
I'm not sure. If so I hope someone responds letting me know before I tackle my exhaust mod possibly this weekend.
 

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Monkey Slut!
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I have a header and deleted my second on my 3.7. Second cat was breaking up and I wasn't about to pay whatever it was they wanted to replace it. Told the guy to just cut it out and weld in a pipe. Fuck the law!
 

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Discussion Starter #5
So in my quick little research through google, I have found that yes it is illegal to to remove the cats from a vehicle. It is against EPA regulations federally and there is also state laws. With that being said, I also found where several people have removed theirs and haven't had an issue. It is one of those laws where if you piss the cop he can give you fine but if don't go around making it obvious you should be ok.
@Jesse since you don't have either cat, what type of muffler are you running or just straight pipe?
 

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Discussion Starter #7
I am thinking of getting a flowmaster 44 or the hooker aero chamber. I just wasn't sure what type of sound I would get if I deleted the cats and went with a turbo thrush or something from the auto parts store. Do you have a header or did you just gut the first cat? What kind of differences did you see once you deleted both?
 

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I had an 18" glasspack with both cats good sound a little loud, then second cat delete and flowmaster not as loud and a slight drone at lower speeds then put on my gutted manifold seen a little power increase and better highway mpg's with a little more drone at higher speeds not anoying but u can hear it, all in all i like my setup sound and performance
 

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True, you are not legally allowed to modify the emissions control system. If your area does not do a visual inspection, or any type of emissions/smog check then nobody will ever know.

It may be a problem at the time of sale, but you can just purchase a new cat and install it before you sell it.

I don't know if it's 50-state or California. But MANY years back I had a cat removed from a vehicle. I could not legally have it shipped to me (moved from a state that didn't require it to one that did). I can't remember exactly the reason, something about not being able to pull it from one vehicle to another (no proof it was going on the same vehicle it was removed from. Furthermore, the local junk yards can't sell you one either.

I guess they take emissions kinda seriously.....? haha
 

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Discussion Starter #10
@cherokeecanyon thanks for the information which is kinda making me want to go with flowmaster. I wasn't thinking duals but I think it may give it better sound and help my truck stay away from the ricer sound with single pipe.
@08Canyon with living in FL we don't have to go through inspections anymore (YAY) so I'm not really worried about the law. Now that I say that I'll end up getting ticketed once I complete my exhaust lol. I don't plan on selling anytime soon, I want to try and take the truck to 200k.
 

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For performance, the first cat is the one you want to remove and still stay legal enough to pass emissions. The first cat is for cold start emissions.
 

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Discussion Starter #12
If I only do the first cat, do I put the O2 sensor back in? I know I will have to do the non-fouler on the second.
 

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Discussion Starter #16
Ok thanks. I may do this tomorrow if I have the extra time. I plan on installing my new interior so not sure how long that will take. Also gotta find a pry bar and air compressor so I can blow all the crap out once I do it.
 

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So in my quick little research through google, I have found that yes it is illegal to to remove the cats from a vehicle. It is against EPA regulations federally and there is also state laws. With that being said, I also found where several people have removed theirs and haven't had an issue. It is one of those laws where if you piss the cop he can give you fine but if don't go around making it obvious you should be ok.

@Jesse since you don't have either cat, what type of muffler are you running or just straight pipe?
So......it's ok for all of us to have to breathe the dirty air from illegal cat-less vehicles? Really? If one is not part of the solution.....must be part of the problem.
 

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OP delete the first and have the second replaced with straight pipe. Add you muffler of choice and then a tune for best results.
 

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Discussion Starter #19
@Joe canyon thanks for the tip. I will probably wait for the tune because I have a couple other mods I would like to complete prior to tuning.
 
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