So first look at the diagram of our exhaust I attached.

I am under the impression that our truck has 2 catalytic converters following the headers, then an 02 sensor, then resonators after the cats. Then it flows to the muffler. I want to cut out the resonator since they are only for muffling and not emissions to make the truck louder. But I keep seeing people online calling them cats. We dont really have 4 cats do we? I just want to check before I cut them off and then have a problem reselling it because of the emission laws. I live in florida though so its not a problem here but if i trade it in the dealers cant sell them without cats.

anyone know for sure?

I mean the fact that theres no O2 sensor after the second housing means it is prob a resonator because cats are usually monitored by a sensor to make sure they work.

 

I only have the two cats coming off the headers if i am thinking right. Im also in Florida. Never had any problems except for one noise violation from a rich neighborhoods police which was later dismissed.

Ive traded in a truck with no cats and a flowmaster 40 on it and the dealership sold it as is within a week. I know because i met the owner of my old truck at a gas station a few weeks later and the truck was the exact same.

 

LOL thats hilarious and im pretty sure its hella illegal for them to sell it like that.

 

Im pretty sure too but they definitely did it. In all honesty, if the truck runs great and is in cosmetically good shape, I dont think they care if the exhaust is missing a cat or two. Just my opinion. I doubt it was just that dealership because i took the truck to 3 or 4 local dealerships, all of whom drove the truck, and said nothing about the exhaust.

About your question, Im pretty sure i have just the two cats and thats it. can go verify and take a couple pics if youd like to just make sure.

 

well I know when i went for trade in to buy my f150 "is the cats still on it" was on their checklist of questions about my trade in because thats like a 500 dollar item. I would keep them on if you want to trade in it. Some places might not ask but many do.

 

Well in my opinion, the two cats after the headers should be enough to satisfy any dealership looking at the truck.

 

Lol! Everything's "illegal" when you really examine context of what your doing. Go walk down the street with no cash or cards on you. You will be surprised to learn that you can be picked up as a vagrant for loitering if you stand in one place too long.

Anyways, you can delete the 2 rear CAT's in the diagram you posted without issue.. As long as you keep the fronts on you technically are still complying with the law. Although it is not a part of the original design, it still functions the same exact way. The second cats are redundant essentially.
Some models with 4 cats with the 2 rear cats that have 02 bungs in the middle of them will require new 02 bungs to be welded in. The other models can delete their rear cats in mere seconds with a quick cut from a sawzall and some fresh (welded or clamped) pipe to fill the newly created distance...

 

i live in georgia. and you have 2 cats and 2 resonators. i took my resonators off, you will be fine with the resonators off, but i would advise to leave your cats. if you delete them, you have a big chance of a valve burning and breaking because of the huge change in backpressure

 

04-05 i believe are the years with 4 cats, and ive read the two rear cats can be deleted with no problem, and seen many people replace the front two with hi-flows.

the 06-08s ive been told only have two cats to begin with. but i have an 04 so i cant 100% confrim on that.

 

Mine is an 05 with a build date of 06-05 and it only has two cats. From my understanding some of the later build 05's only have two cats. I was assuming mine had 4, so I crawled under it and it has two.