im thingking of taking all my cats out(all 4) in favor of straight pipes.
my questions are as follows...
1.would i gain better HP since the 5.4 has a procharger(what about back pressure)(PROs N CONs?)
2.guess ill need some MIL illiminators for the 4 O2 sensors,right?
3.should i go with H-pipe,Y-pipe just a straight connection of both pipes going to the muffler?
4.forget taking the cats off
5.how does this effect as far as emmision test?
6.would i need another tune?
7.anything else i should look out for if/when i do decide to do this?

its a 5.4 ford expedition with a PROcharger and NOS kit

thnxz for the replies,guys

 

1. yes you will see gains
2. you only need the MIL eliminators for the last 2. DO NOT DO THE UPSTREAMS
3. Your best bet would probably be true duals with an x pipe
4. thats your choice
5. you will fail...... duuuuuuuuh
6. maybe, you will probably lean out about .5:1 at WOT
7. the cops....... as removing the cats is probably illegal

 

i have a set of Down pipes that my local muffler shop fabed up for my 4.6L From manifolds back to get rid of the cats. they have the flange and Front o2 bungs *in the right place* i have a 97 F-150 4.6L 2WD *These should fit right in* i only had these down pipes on for about 5,000 miles the pipe looks brand new i took them off to put long tubes on....What year truck do you have?

*i gave him my stock down pipe from the manifold to the end of the last o2 and he mocked it up with his bender so he could get all the bends the same and the right place for the front o2's*

 

just hollow em out bro thats what i did to mine..i love the sound and the check engine light only comes on if you miss a spot welding it back up and theirs a hole in the exhaust....hollow em out...that a way you can still pass inspection...and keep your foot out of it cuz itll be loud and cops will getcha...believe me i know

 

lol yeah thats not a fun ticket my buddy on his lifted K-10 was running open headers and got a 500.00 dollar ticket for it... haha I didnt run just pipes after the down pipe i put dynomax superturbos...those made it really quite

 

It will pass a visual inspection but not the sniffer test if or when his state requires it.

 

one of the few good things about michigan NO emissons testing at all!! woot woot!

 

thanks for the replies guys.
as far as the sniffer test...i live in chicago and for the 00 and up cars/trucks/SUV..there is no more sniffer test(hell..the guys dont didnt even looked under my truck when i had it checked last nov.)
a friend of mine that has an 00 mustnag had all hiscats taken off and just running straight pipes going to the X-pipe and he told e the same thingas far as no sniffer on his car neither.

heres another question...if i just hollowed out my cats and add the MIL illiminators to the 2 back 02 sensors..would that be enough to keep me off from getting CEL or theres more steps im missing?

BTW..im also running a bassani system(muffler to exhaust with single pipe)
thanks again guys.

 

Did you Gut all 4 or only 2? if you only Guted 2 you dont need MIL for the o2's they will still read fine with only 2 out of 4 working. If you guted all you should be fine...Take it to autozone to make sure or find someone with a nice nice scanner to make sure there working right.

 

i cut the 2 big ones off and gutted the small ones

 

I replaced the 4 stockers w' high flows and it's running like crap right now. I'm replacing 02s so make sure you keep the front ones and if they aren't showing bad right now they might after you remove the cats. That's what mine did. Let us know how she runs after the mod.

 

make sure you reset your computer by unhooking your battery after you did it

 

Oh yeah, I unhook it before I start not just after. Prolly the same difference, right?

 

yes same difference, just unhook it as soon as you can

 

FYI - I passed the CA sniffer with two Magnaflow high-flows, gutted pre-cats and a Procharger.