exhaust clarification...

[jlo82585]

I have seen many different posts about the exhaust on the 5.4l and they are all different as to how many cats the 5.4 has. can I get a solid answer? does it have 2 or 4? its 30 degrees out and raining so I really dont want to crawl under my truck... if it has 4 am I able to remove the rear two without setting off the CEL?

 

[tonydiv]

The cats themselves won't set off a cel, it's only when you remove the O2 sensors when the issues start.

The truck should have 4 cats, and several people here have deleted the rear ones without any issues. From what I've heard, it also improves the sound considerably.

 

[toms89]

There are 4 cats as said.

There are also 4 O2 sensors as well. The 2 upstream sensors, banks 1 & 2 is what the pcm uses to tune the truck. The downstream sensors are solely for monitoring the effectiveness of the cats and used for monitoring emissions.

Many have removed the rear cats with no issues of setting any cel's. If you remove all 4 cats you most likely will set a cel and not pass emissions. There are ways around it like turning off the rear O2's in the tune or use of non-foulers but am not in any way recommending this.

I am running 4 cats with my custom exhaust currently.

 

[rollavvti06]

ive used non foulers on my supercharged corolla with good results.

 

[jlo82585]

okay thanks, does anyone know what the pipe diameter is on stock? I have heard its 3in to the cats then 2.5in on back?