[textitan13]

I believe they have 2 pre-cats and 2 cats. not sure on the legality of removing them though

 

[ToreyC]

that answers one question. anybody else know the answers to the rest? what is the point in a pre-cat and how important is it to have them? thanks for the reply by the way.

 

[textitan13]

okay looked it up a little. i think the precat is supposed to warm the air a bit before it goes to the cat, so they can operate at the right efficiency during cold weather or just after you start it. the guys at the nissan dealership told me they were removing the precats to put on long tube headers, they just had to move the o2 sensor because they removed the pre cats. so i would guess you could technically get by without them as you would still have cats. but someone correct me if im wrong

 

[troutstitan]

I have a Question about the drone. I to have the same truck and year 4x4 plus the dual Magnaflow , love the sound ,good volume but resonance is killing me . Any Ideas about changing that I e wrapping the outside of the muffler with something ???

 

[rgregory1965]

I have a Question about the drone. I to have the same truck and year 4x4 plus the dual Magnaflow , love the sound ,good volume but resonance is killing me . Any Ideas about changing that I e wrapping the outside of the muffler with something ???

I have read threads that will say if you shorten the lenth of the pipe after the muffler the drone will go away....I have the magnaflow also and get a pretty good drone between 1800 to 2000 rpm......

 

[ToreyC]

how much would those headers cost, and how much would it help the sound and performance of my truck? is it legal to take the pre-cats off if u are going with headers? thanks for the info. so far.