OK, so I am new here and i have been searching for days. I have a 1997 7.5L 460 f350 4x4 auto RCLB. I had looked at the banks power pack and plan to get that eventually or something along those lines like headers etc.. so my question is, i had just bought this truck awesome shape runs great only 73k orig mi. previous owner had chopped off exhaust past cat. I have looked for days to get an answer or some opinions or options. I would like for the time being to gut the cat. I am not opposed to and would rather cut it off but I am unsure if it will throw any code because of the o2 sensor? I don't want to remove smog or anything with the ERG i want the truck stock except for exhaust components. I would love to just do the exhaust and leave stock manifolds but i don't want the lights on my dash from codes being thrown. I live in WV so emissions is not an issue and i can get my truck inspected without a cat so i have many options. so basically what i am asking is if i delete the cat will it throw a code, or do i leave the cat and gut it?? will that throw a code?? and if i just gut the cat will i have any issues if i don't put a muffler on it and just leave it open after the cat? like back pressure or running any worse or anything. I know the big thing is these 460's need to breathe!!

 

Oh and another thing about my above post is it even worth it will i notice anything or even if i dont notice anything will it help engine performance any if i do any of the stuff in my above post?? all help is appriciated thanks in advance!!

 

Hmm. I took a piece of re-bar and completely destroyed the inside of the cat on my 03 5.4 to where it is just a totally empty shell. I don't know the differences in the systems, but it didn't cause any negative effects on that truck.

I know that isn't exactly the info you need, but thats the only 2 cents I have in my pockets.

EDIT: I was able to do that very easily because I have a straight-through magna flow muffler and no tail pipe after it.

 

so it didnt trigger any check engine light or throw any codes? andi dont see the difference except appearence with gutted cat vs no cat its free flowing once the honey comb is out of the way. and thanks

 

If the existing converter is functioning properly you will see little to no difference in performance or fuel mileage versus a gutted or cut-off converter. The converter used on the larger F-series truck is not a huge bottleneck like the dual converter setup on the F150/Bronco.

 

But it sounds better

 

Ok thanks. I want to put an exhaust on it i think but I don't think it will sound god or very loud with the converter but I'm afraid if I take the converter off or gut it it will throw codes. So I'm kind of stuck here. The only reason I say gut it is because I can leave the airlines hooked to the converter along with the o2 sensor hooked up and have a cleaned out cat thanks again!

 

Put a free-flow cat on it, problem solved.

 

Personally, I've heard good things about the magnaflow cats, I just went with the cheaper alternative, and no I never got any engine light on the 03. However I did get one when my exhaust manifold cracked.

I also have an electric cut-out situated in front of the cat, so when I want the really loud sound I run it open manifold.

 

So if I put a free flowing cat on will it not trigger the post o2 sensor and throw a code? I don't have a problem with free flowing cat vs. no cat I just want to get rid of that big freaking can underneath! How do the guys running no cats keep the o2 sensor from throwing a code or do they just not worry about the code and if I take the stock cat off what do I do with the air lines?

 

A free flow cat won't set off codes, it's just as efficient as your original if not more so (provided you get the appropriate sized one) so the downstream O2 sensor won't see any change at all.

 

What do you mean by appropriate size? And will any of the other o2 sensors be effected? Is a free flowing as good as or close to no cat like in flow and sound? And what do I do with airlines?

 

Your 1997 could be using an OBD-I system which uses only one O2 sensor before the converter. If the truck has California emissions it will more than likely be running an OBD-II system with 3 O2 sensors. One in each down pipe and a third located behind the converter. It is this third one that can cause issues with turning on the Check Engine Light.

You need to check the VECI label under the hood to see which control system your truck is running. OBD-I, easy to remove a converter or run a high-flow with no worries of a CEL. If it is running OBD-II there are pitfalls to be aware of.

As far as converter size is concerned you need to consider the engine size as well as the GVW rating of the truck when selecting a converter.

 

It's OBD-II and I have narrowed it down to 2 options either put a high flow cat on it and weld a bungs in for the o2 sensors or just cut the cat off and and stright pipe it with a muffler which I haven't figured out which muffler yet and when it throws a CEL just pull the bulb.