Okay.. So I just chopped off my muffler and all tubing after it. I like the sound but am afraid it may cause something to burn up.. someone told me the valves may burn up or something..

But anyways, I'm looking to make the truck as loud as possible.

Can someone explain to me which cats are precats? and which are just regular cats.. i have an '02 5.4L f150. I've got 4 cats altogether.. i want to know what I can eliminate for that beefier sound without getting CEL.. and is it okay to go without a muffler or can I put a muffler on and still get that very loud deep throated beefy sound..

thanks in advance

 

also want to make sure that if i leave my truck without the muffler that it won't harm my truck at all

 

You can cut out your rear cats, it goes cat-02 sensor-then your other cat. You can cut out the rear cat and run a straight pipe, shoyuldn't hurt anything and shouldn't trip your CEL, Running that set up on my 04 and it runs fine,No CEL and sounds AWSOME!

 

yes cut out the rear (main) cats, and running it with no muffler will work. i ran that on my 98 f150 4.6L, it is very loud.

 

darren correct me if im wrong but if he cuts off the rear cats on this model there is a chance of gettin a CEL. the front ones are the ones that need to go. and its the opposite on the new body style 150's.

 

The front smaller converters are the pre-cats. The round ones behind it are the rears.

If you remove your rears you are at a small risk of a CEL due to the rear converters contain a bigger catalyst that filter gases more. The Pre-cats do the same but not as much, they mainly resonate sound in 1997 - 2003 models. Your best bet would be to remove the pre-cats and leave the rears as is, or get hi-flow converters.

False. He has a 2002, and from '97 - '03 its front O2, pre-cats, rear cats, sensors.

Our models have the rear sensors after the front cats and the rear cats unmonitored but trucks assembled after January 2005 and newer have two larger converters with O2s in them.


Its true, but most people dont report CELs after doing so. One guy stated he gutted his pre-cats and removed the rears and had no CEL, I dont understand how that one works... But if its true, I guess he got lucky, but I wouldn't doubt he will get a CEL after a little while.

 

The front cats are the same composition as the rears, however due to the locations of the 02 sensors, the PCM only monitors what happens in the rear cats, as far as catalyst efficiency.

On any vehicle, front 02s are A/F ratio monitors, and rear sensors monitor catalyst efficiency

Wrong, its Cat -> 02 -> Cat -> Downstream 02

Sorry to burn you twice


But yes OP, if you want to gut, or remove any cats without worry about codes, gut the front cats (Pre-cats) They are called pre-cats because they are not monitored by the PCM

 

Would the same go for my 01 4.6?

 

yes. your cat setup is the same as the 02's and my 01. basically all of our same body style trucks are the same.

 

97-04 is the same.

 

thanks, thats what i was tryin to say lol

 

Haha, no problem man.

 

Just to verify~ I can take out my pre-cats completely and just replace them with straight pipe and it will make my truck louder without CEL?

 

yep. its gonna take a bent piece of straight pipe for the pre-cats though. the rears will literally be a straight piece of pipe.

 

Well put and correct. As long as you have a '97 - '03 model there will be no problem with removing the pre-cats.