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-   -   Will No CATS HURT my truck (https://www.f150online.com/forums/exhaust-intake-systems/273278-will-no-cats-hurt-my-truck.html)

Justin97 02-13-2007 10:14 PM

Will No CATS HURT my truck
 
I drive a 97 f150 with the 5.4 if i have both cats removed but leave the resinators will it affect anything at all

ford-bob 02-13-2007 10:18 PM

i don't think it will give you any problem... i did the opposite with an '02 i took the resonators and mufflers out and left the cats. it didn't do anything. i know plenty of people who run them with nothing at all and they haven't had any problems.

built54 02-13-2007 10:22 PM

wont do anything, just set a CEL... and smell really bad. Just cut all 4 off and buy 2 high flows, it will burn cleaner, sound awesome, and wont set a CEL...

Justin97 02-13-2007 10:55 PM

will it not make my truck run ruff if i dont put nothing back under it

ford-bob 02-13-2007 11:01 PM

my diesal ran fine and there trucks seem to run right... you have to put a smaller pipe in where the cats were so that it will give you back pressure. just thought of that sorry.

way fast witey 02-13-2007 11:10 PM

diesels didn't have a downstream o2 sensor. if you remove 2 of the 4 it will be fine. if you remove all of them you need a 1/4 ohm resistor in the signal wire on the downstream o2's and it will be fine. i also reccomend just replacing all 4 with 2 high flows i have no cats and i would like to add 2 high flows when i get the money

BlackedOutF150 02-19-2007 01:14 AM

what is the purpose of removing 2 of the 4 cats? any increase in performance or just sound?

Patman 02-19-2007 01:23 AM


Originally Posted by Justin97
will it not make my truck run ruff if i dont put nothing back under it

Well yes and no, yes it will be fine, but just want to make sure you arent thinking of daily driving a truck running open manifolds, and no pipes....


Originally Posted by way fast witey
diesels didn't have a downstream o2 sensor. if you remove 2 of the 4 it will be fine. if you remove all of them you need a 1/4 ohm resistor in the signal wire on the downstream o2's and it will be fine. i also reccomend just replacing all 4 with 2 high flows i have no cats and i would like to add 2 high flows when i get the money

Cool! So the O2 sim is just a resistor?

hllon4whls 02-19-2007 01:25 AM

On a stock truck, or one with just an intake, I dont see how cutting the cats will help much. You might get 2-5 hp, but that is not going to really make a differenece.

Just an FYI, it is a federal offense to tamper with the emissions system on a pollution controlled vehicle. Why risk it for such a small gain?

chester8420 02-19-2007 01:31 AM

1. Your truck will run exactly the same with or without cats.
2. You will get a check engine light without cats.
3. Your gas mileage will not go down without cats.
4. Your power will not go down without cats.
5. Your exhaust will smell like raw fuel without cats.
6. You will have to turn your truck off at drive thru's or any time your window is down to keep from stinking yourself out. (just like a diesel)
7. Your truck will be louder, both inside, and outside the cab.
8. A set of mil eliminators (under $20 or make them yourself) will fix your check engine light.
9. You will probably regret cutting them off. But maybe not.



Originally Posted by Patman03SprCrw
Cool! So the O2 sim is just a resistor?

Nope. That will not work. You have to have an RC circuit. I'll post a link on how to make one tomorrow.

Patman 02-19-2007 01:32 AM


Originally Posted by hllon4whls
Just an FYI, it is a federal offense to tamper with the emissions system on a pollution controlled vehicle. Why risk it for such a small gain?

I noticed more torque, and more top end (hp) power.... and i did it to where you would have to take the heat sheild off of the cat just to even get a glimpse at the top side of the cat where i gut a small window out.
-Patrick

chester8420 02-19-2007 01:37 AM


Originally Posted by Patman03SprCrw
I noticed more torque, and more top end (hp) power.... and i did it to where you would have to take the heat sheild off of the cat just to even get a glimpse at the top side of the cat where i gut a small window out.
-Patrick

Mine are gone. :devil: A piece of pipe in their place.. Oh well, the CBI will get me soon. (catalyst bureau of investigation)

Patman 02-19-2007 01:42 AM

yah eventually ill cut them back open and run a pipe through the middle of the housing, for even better flow characteristics, and the exaust wont "pop" as much when i rev, or coasting. (not that its obnoxious now)

chester8420 02-19-2007 02:01 AM


Originally Posted by Patman03SprCrw
yah eventually ill cut them back open and run a pipe through the middle of the housing, for even better flow characteristics, and the exaust wont "pop" as much when i rev, or coasting. (not that its obnoxious now)

Yeah, My precats were intact until a few weeks ago. I gutted them, and now it has that "header ring" to it.

Justin97 02-20-2007 06:24 PM

thanks for all the great advise the main reason i wanted to cut them off is because i think the right cat is getting stopped up its makin a funny noise and plus were im from everyone drives chevy's and rag my ford cause it aint as loud but i still pull of and leave them in the dust everytime


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