Hey guys I have a 2000 f150 with longtubes 3"cats and 3" tubing all the way back. Wouldn I gain anything by changing tut back to 2 1/2" tubing? Ive heard that backpressure issues are pretty much hog wash with a good tune but do these motors run better with 2 1/2" opposed to 3"?

 

My engine is the 5.4 btw

 

I'm also interested in knowing about pipe size. I have a 2007 F150 with the 5.4 in it. I'm planning on getting the 14" Magnaflow part number 12198. I was gonna run the dual pipes and hide it behind the rear bumper and was curious what size tubing to use and if having no tips would make a big difference in sound. I have no performance mods done and didn't know if changing the pipe size would anything bad. THanks

 

Greg, 2.5" is good to keep most of your low end. 2.25 is best, but if it's not mandrel bent, 2.5" is the way to go on these trucks.

Ray, I have that muffler with high flows on my truck. It's a 3" inlet and dual 2.5 outlets. Two ways it can be done usually. The intermediate piping from the factory y pipe (where the piping after cats comes together) is all upgraded too 3" and go into the muffler or (which this is how mine is) the shop butts the 2.5" intermediate pipe about halfway to new 3" pipe to go into the muffler and then the dual 2.5 piping after the muffler

 

2.5" will be better yes.