I have a 06 f150 5.4 with Flowmaster 40 series SIDO muffler. I was gonna ask if I cut the muffler off and replace with a y-pipe and leave the factory cats if I would lose any backpressure or throw any codes or anything. I was wondering cause I did this same setup on a Chevy and about a month later, I was replacing the cats and air intake gasket. I dont know if cuttin my muffler off was the cause of that problem but dont wanna get into a situation like that again. Thanks in advance everyone!!!

 

It will run alright, these model Fords dont break down easily. If anything you may lose a tiny bit of low end but it wont even be noticeable unless you put your truck at a true challenge ( hauling 8,000lbs )

 

I actually ran that setup for about a week haha. You'll lose a little more low end than with the 40 series, not much notice unless as Darren said, you put it to a challenge. I had no problems with it though.

 

Thanks for the replies. I just didnt wanna go down that road I went down before. I'm not sure what I wanna do yet. It's between cuttin off the cats and leavin the muffler, or cuttin off the muffler and leaving the cats and maybe puttin some hi-flows on if im not happy with the tone. Which would yall do? I had an 04 cobra 4.6 3V a while back and had the cats cut off with x-pipe and dual flowmasters and cut the o2 sensors off with my programmer and it sounded great IMO. Will I have to do that with my truck if I go that route or is there other ways around it? Where in Bama are you located Bigdog?

 

I'm more prone to no muffler, or hi flow cats and muffler that's the best route to go, IMO. Hi flows and flowmasters would be nice. I'm in Gumptown haha.. You?

 

Athens...its close to Huntsville

 

Ah cool, my dad does work up in Huntsville at Redstone. I'm assuming you know what Gumptown is? lol

 

Would it be Montgomery

 

Greenbow?

 

Yes it would


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