I have an '08 F-150 with the flex-fuel 5.4l, I'm trying to redneck it up a bit. Recently i unbolted the stock exhaust just before the muffler, and put on a straight through muffler, but I'd like a bit more noise. How many cats (if any) can be cut out without throwing codes, and are there sensors in all of them?

 

Two cats, with a sensor before and after each. Can't take one out without throwing a code.

 

FYI its illegal to remove any cats and they are very expensive to replace. Also if you take any out it will "throw" a code. The PCM monitors both cats for efficiency.

 

ah, I guess I should just get used to the sound I've got!

 

I always thought the o2 sensors were in front of both cats. Well thats what someone told me

 

If you put a straight through muffler on it and didn't get enough noise out of the truck then you are deaf. Maybe try adding a larger pipe to get some more noise.

 

Nope, one fore and aft of the cat. The sensors let the PCM know if the cat is working efficiently. If they're not it throws a code and you can't pass inspection.

 

Other than throwing a code and the inspection... is there any mechanical problems with removing the cats?

 

Mechanically, no. Federally, yes!

 

dump the exhaust as close to the cab as you can and it'll be louder than running it out by the tailgate. I wouldnt end it under the cab though or you'd have all the fumes running into it.

 

Unless one of the cats is bad,leave them alone...if it is replace it.Removing them will cost you economicaly,and definately cause issues down the road.

 

what about a set of high flow cats and look at the exhaust cutout's one 2.5 before the muffler that would redneck it up a little but you can go back to normal exhaust when you want to. (im looking at this one)
BadlanzHPE Electric Exhaust Cutout Cutouts 2.5 INCH S: eBay Motors (item 180375536259 end time Nov-21-10 15:39:35 PST)

 

I kept the original exhaust diameter (2.5") and have a 30" tailpipe after the muffler (installed backwards to bypass the baffles), which dumps straight down in front of the back axle. Maybe I would hear it better if I turned down the music

I appreciate all the responses, and I suppose I will just leave the cats alone, and be glad that the law hasn't told me to quiet it down, or remove the second round of tint this year.

 

This is the cheapest and quickest way to get some major racket. Be sure to weld on a turn down, piped curved pointing to the ground, if you dont u will wind up rustin out the bottom of the body...

 

Another bed floor rust canidate