I am wanting to remove the cat from my 2001 F250 5.4. I am just wondering if there could be any ill effects that this could cause? I will remove my cat and go into a flowmaster exhaust, and dump it right in front of my rear axle. Could this cause any problems with the engine?

 

the only thing i can tell you is this . i have a 95 4.6 bird . the obd 2 system can / did handle the changes to the exhaust when i put the true duals on my car . a 2 inch system with flowmasters . in order to pull the cats and not have it throw codes at me i have to A: have the chip retuned for it without the cats and / or remove the rear o2's at this time too . B: get or build a piece they call an mil that slows down the rear 02's readings of the systems flow .i found a thread on another site where the guy made his own for both the rear o2 sensors on his bird using 4 sprk plug non foulers for a 70 merc montego w/ a 302 . he drilled the 2 bottom ones base out with a 1/2 inch bit , then put the o2's into the untouched ones . installed those in the drilled ones , and put them in their respective spots on both head pipes . the reason for the specific car non foulers is they used the same thread pitch as the o2's . this enabled himas mentioned to pull the cats and not get any codes . now on your newer truck i dunno . maybe someone here can answer you on that , i was just trying to give you some ideas as to what others and i are doing to accomplish this . check with sct or blue oval chips for an new chip to retune if thats the way you want tog go . one is in my carsfuture for more POWER !!!!!!!!!! can never have enough .................

 

I cut the cat off my truck about two months ago and have had no engine problems. Not sure if they have different emission standards for these trucks but mine had no downstream o2 sensor to worry about. I think it is due to the gvw and what standards were for that year. I went with a flowpro muffler and 3in pipe and it sounds great. Also seemed to free up some power. Now I just need to find my supercharger.

 

I've often wondered; does the new sound make it seem to have more power or does it really have it. I think only a dyno or timed comparison would really be the answer.