Just got Magnaflows for my 5.4. Should I remove at least two of the converters or leave them alone?

 

Since tampering with working emissions equipment is illegal, and if you live somewhere where there's smog checks or state inspections, you might get popped...I'd say leave 'em be.

 

If you take the two rear cats off it will be considerably louder, that’s for sure. Two Magnaflow cats can replace four stock cats and still be completely legal

Magnaflow 2.50" IN/OUT High Flow Catalytic Converter

On vehicles with 4 catalytic converters (2 cats on each side of the motor), you only need 2 of these cats, 1 on each side, to replace all 4 factory cats

 

Well unfortunately passing a smog check and being legal are two different things. I'm not sure how it is where you are but in CA you can't legaly tamper with smog equipment even if it improves emissions.

 

im removing all of mine in the spring and replacing them with 2 magnaflow highflow round cats.

 

Don’t know about CA smog check but the Magnaflow cats do have CARB emissions certification

 

Legally you're not allowed to change em unless they've failed in some way. I'm not sure how that is proven either way but that's the law.

 

I took all 4 of mine off and put a imco muffler on, it was waaaay to loud so i put high flows [2] and a magnaflow muffler, it has a real good throaty sound ! def not loud enough for me but thats why i am getting eletric cutouts, if u replaced the 4 cats with 2 high flows and a magnaflow u will love the sound, if u want all out loudness just get the 4 taking off, only problem is it attracts unwanted attention from the cops and also when i had my old exhaust i had no-one say it was quiet ! these 5.4's can be loud as hell when u open them up !

 

Im sure, just like ur 20K sound system. You know monday came and went and I havent seen any pics of your lifted truck yet.

 

Would you get a CEL with them? Would you lose any low end performance? or gain? Im pretty interested in getting some when I have some extra cash.

 

Ya, and throw codes left and right because the o2s dont know what the **** is going on.

 

I'm removing my rear 2 cats next week... Ford did it in 06 so why shouldnt I?

 

Fatherford, So with out me going to the dealership and crawling on the ground. The 06' model year fords are running only the front two cat's?

If this is the case, it would be interesting for someone with an 04-05 to drive a 06 and see if they feel anydifference? Thank god I live in the arm pit of America...errr...Indiana I could run open headers and no one would care. (infact I think some obnoxious sob's do????) I would be all for cutting the rear two out and leaving the fronts.

When you do cut the rears, keep us up to date if you feel anydifference, or throw and CEL. Thank You.

 

I'm not for certain but when I did my first oil change and looked at the exhaust...I thought I saw two resonators coming off the headers and two cats and then one LONG @$$ muffler...I believe I only saw 2 02 sensors too...I plan on putting straight pipes on my truck without taking any cats off. I did this on my 99' 5.4L and it sounded perfect. Not too loud, not too quiet. Who needs mufflers?!

 

From what I have noticed, is that somewhere in the late 05 run ford went to two cats on the 5.4l's.

There are a total of 4 o2 sensors. The first 2 are right off the exhaust manifold before any of the cats. The 2nd set of O2's are after the first set of cats. By removing the back cats you will not see any lights show up due to that the last set of O2's are BEFORE the rear cats. The rear cats can be easily cut out and replaced with a straight piece of pipe.

Also a tuner, such as the diablo or SCT can "turn off" the back set of O2 sensors. I'm unsure if edge can or cant. I no superchips and hypertech cant. Troyer will NOT turn them off. I repeat he will NOT turn them off. This has been told to me by 2 individuals that requested he would and he refused.

Unfortually I can not tell yall if my power gain, if any, is from cutting off my rear two cats. Cause i'm not only cutting off my cats, im also true dualing with a magnaflow dual in/out with the built in x-pipe. I currently just have a piece of straight pipe dumping after the Y. Which very surprisingly doesn't sound randy, crackle, glass pack like normal straight pipes do.