All, I want to put an exhaust on my 2008 F150 King Ranch... I want something that sounds good when accelerating, but is quiet on the highway... I want no drone... I also want something that is not going to suck torque or horsepower from my truck (I frequently tow a boat).

From reading tons of threads I have decided to go with a Magnaflow, probably SI/SO 22", and a stainless rolled tip. I was thinking that I would just keep the rest of the factory pipes since they are good anyway.

I went in to talk to a well known muffler shop today and do some shopping... he said that for an extra 160 he could trim the Y pipe some so that it would dump into a bigger 3" pipe instead of the factory 2.5" pipe. From there he could have that go to a three inch Magnaflow SI/SO. He said that this would help power and gas mileage.

I am a little wary about dropping the back pressure too much because of threads that say the 5.4 liter engines rely on some back pressure to increase low RPM torque.

So my question, should I just get a muffler and tip, or should I replace the pipe from the Y to the muffler with a slightly bigger one too?

Thanks in advance for your opinions.
Anthony

 

While decreasing back pressure can cause you to loose low end torque, any decent cat-back exhaust system will have enough back pressure. I would highly recommend the MagnaFlow cat-back exhaust system.

 

Thanks Matt... I am not currently looking to purchase a cat-back system, just looking to have a muffler shop customize the exhaust for me. From looking at many posts I think it will be more cost effective this way... is there a strong reason not to do this?

 

Your stock cats will give you more back-presser then you'll ever need!
It's up to you weather you want to spend the extra money on 3".It's not going to make a big difference ether way you go.

Phil

 

Sounds like you would like Corsa.

 

Dynomax bullet has zero drone if you run them out past the axle