I have a 4.6 with Factory SISO Exhaust. I am changing my Y pipe And muffler for alittle less restriction. I plan on staying with SISO.I want to get a Magna Flow Y and MagnaFlow straight threw Muffler.But I'm really not sure if I should change to 3" after the Y or stay with 2.5. I don't want to lose any low end power,Do to I tow quite often. What do you guys think 3" or 2.5 after the Y. Thanks for any input.

 

with you towing and not looking to go to forced induction anytime soon, I'd forget the magnaslow Y pipe and magnaslow muffler as they won't do anything but change the noise your truck makes...


IF you are dead set on changing the stock mid-pipe Y to the magnaslow Y you might want to consider having the dual 2.5's into a single 3 inch thru the muffler on out

 

Magnaslow

lol, you had me going for a second!

 

Never had Magnaflow before but I would love to hear someone with those mufflers in person. YouTube videos don't do them justice!

 

Thanks for the quick reply tarajerame. I have to replace the intermedate 2.5 pipe between the Y and Muffler because it has had 2 leaks in the past 4 months that I welded for a quick fix. Now I have a little extra money I figured I'd change the Y since I will be replacing piping in behind it to Stainless and a new muffler, any way and possibly changing to 3in the rest of the way if it didn't take from low end power. I only was going to replace the Y because I have read that it was poorly designed, restricting the driver side of the motor less that 2.5. Hope maybe I could get alittle extra power.