right now i have a 2004 f150 fx4 and i have a S&B intake and true duals with X pipe. and i have the gryphon with the custom tunes for my truck but will it hurt anything if i delete the rear cats or cut everything off and put highflows on their.. in other words do i need to get different custom tunes if i do this..

 

I don't believe you would need new tunes for cat removal or swapping to high flows. I could be wrong, but I think it's more important to correct for the increased air flow in with intake rather than out with exhaust. Someone else wanna jump in and correct me if I've misinformed him?

 

ya im not sure what will happen? i got my pipes done about 3 years ago at a really good custom exhaust shop in New Castle, PA they do pretty much 90% of the trucks you see with pipes in new castle. and being that my truck is a 04 with the 4 cat system its still pretty loud with true dual coming into a X pipe "No muffler" and 45'ed out the back. but my friend just bought a 07 and he got the same setup true dual's X pipe "No muffler" out the side like mine and his freakin screams.. it has so much more growl,rumble,volume and its because the 04's-05's suck for getting any volume with the 4cats so i need to do something but i dont want to have them cut everything off and put 2 new maggie highflows on their into x pipe and out the side again if its going to screw my custom tune up...

 

The question is, are the changes you're planning going to have any appreciable effect on back pressure to the engine? My gut feeling is no, but I'm by no means an expert in exhaust design.

You may want to ask your question in the exhaust section.

- Jack

 

ok thanks guys.. i just want to cut the rear cats off or just put high flows on to have a little more sound thats all.. i just didnt want to start doin this stuff and find out it would screw the gryphon all up..