does anyone know the length of the stock cats on a 2004 f150?

 

Front ones are 11.26"s, Rears are 12"s.

 

i thought we only had 2 so whats front and rear

ps i have new body style

 

1997 - 2005 years trucks have 4 converters.

'97 - '03 the fronts are 6.75", rears are 12".

2004 and early model 2005s have the 11.26" pre cats and 12" rears.

Trucks built January 2005+ have two 16" cats, 1 per bank.

 

Whoa i guess i haven't been on this section for a while, it's empty!

Sorry, a bit off topic. lol

 

Yeah man i've been bored all weekend, no bodys asking alot of exhaust questions

 

hey Darren, I deleted my rear 2 cats, and DAMN is it louder... now I'm glad I got that done before I ordered my muffler. I'm gonna go with a 18" body rather than the 14" as originally planned.

 

Awesome man. I got mine out and 11" bodies and still want more sound

 

Darren, you are the man with the answers. I live in Philadelphia and have to pass that emissions crap. Can I cut out the rears without throwing a CEL? I would love to have them out and then put in my Flowmaster Super 44.

 

You wont get a CEL with the rears out no, but... you wont pass the sniffer test for emissions, or the visual. I wouldn't risk it.

 

I guess my truck is an in between one, '05 Supercab w/ 6.5' bed; built in 10/04 and I only have 1 cat per bank, the exhaust Y's right after the driver's side comes across and makes a long single pipe run to the muffler, cats are right beside transmission. Judging from the rust all the exhaust is oem only recently replaced the exhaust with a magnaflow cat back system and I used the 18" intermediate pipe instead of 24" from the kit even though i have no second cats because thats what worked out with the factory hangers. I believe i will replace the pipe from the Y to the new pipe on the muffler, about 18"+, makes so since to have a 3" exhaust system with a long run of 2.25" in the middle.

 

18" - 24" intermediate pipe? Are you talking about the length of the muffler? If your intermediate pipe is that long, its much too short, but I believe you meant muffler. If your going to replace your exhaust pipe with a newer pipe with to bend, dont downsize it to 2.25" because your choking the truck and causing un-proper flow to the muffler. If it has a 3" inlet, it needs to have a 3" intermediate pipe from the Y.

I would get the Magnaflow Y pipe connector thats 2.5" dual in and 3" single out ( $24 ) and get a shop to install and run 3" piece of stainless steel pipe to the muffler, then your exhaust will run great.

 

my Expy sounds like a dadgum straight-piped semi now that I have my rear cats out. I'm getting my 4"dia.x22" magnaflow replaced with a 12279 and 3" y-pipe-back on Friday.

EDIT:

crap...I forgot now this belongs in the AFTERMARKET section...

 

The 18" and 24" intermediate pipe which necks down to the oem pipe is what is supplied by magnaflow. When I said 2.25" i meant the existing pipe which is instead 2.5". But a picture explains it better. Bascially this kit is meant for someone who has the 2nd set of cats.



Please excuse the rust; truck came from MN.

 

Oh ok. If I had a cat-back I would replace the entire intermediate pipe from the original Y, that stock Y pipe is restrictive being dual 2.5" to singe 2.5"