will cutting off the 4 cats on a 04 f150 5.4 effect anything

 

Why not just take them out and replace them with high flow cats?

 

failed inspections/emissions testing possible fine/impound of your truck

cut the rear converters off, they arent monitored, that or cut all 4 off and replace the front ones, the ones that ARE monitored with magnaflow converters

you will get a CEL if you cut the converters off without a tune and probably wont run right

 

cheaper to just cut em off i took them off on my 98 f150 without any problems i was just wondering if a 04 f150 would be the same

 

why do you want to cut them off?? if your looking to louden up an aftermarket system just remove the rear ones yourself

 

Remove the rears. Stay legal that way, and still possible to pass a sniffer test if fully warm. $30 in supplies, $50 or so if you buy stainless piping with clamps.

 

Not if you tune or do the "gotts" mod on the o2 sensors. No kitty for me!

 

darren, are you saying that theres a possibility that one may pass the sniffer even with the back 2 out??
ive been wanting to do this for so long now but i dont want to fail inspection and cant afford hi flows right now.

 

Technically yes, I cant prove this, but a bud of mine with a 2002 chopped all his cats out and cleaned them out, ran pipe through the rear cats and left the pre-cats open without feeding pipe, and runs a SI/DO Magnaflow system and claimed he passed the emissions sniffer. He said he made all his errands and a couple WOT pulls, and went to get it checked out and it burned clean enough to pass the sniffer.

These engines are much cleaner burning than the older ones so I can believe some of it. So if thats the case, I can definitely see my truck passing a sniffer test if fully warm 190+ degrees. My exhaust smells a bit cat-less on cold starts, but otherwise it never smells bad when warm.

 

dang.. well its kinda sketchy though. idk if i wanna risk it. lol
those back ones may be coming out next week though anyways. ill be out of school and ill have lots of time
i know you can clamp the new pipe on.. but it really doesnt seem like theres much room to clamp.