am going to run a single in dual out muffler on my truck. I have read many threads debating the best size to run. My question is this: Should I run 2 1/2 or 2 1/4 dual tailpipes? My truck has the 5.9. Have any of you that have the dual 2 1/2 tailpipes lost any low end?
Thanks

 

yes they do, that's why you should go with 2.25's

I speak from experience on my truck with the 5.9 liter motor

 

If you are running dual pipes after your muffle shouldnt matter what siz you put on, you could out dual 4 inch if you wanted. All the pressure is gonna fter it exits the muffler. Personelly i run you single 2 and a half in and then 2 and a halfs out, personelly i like bigger rears, but i dont like to loose my power, pretty sure stock its 2 and a half right. Drop some headers in go to 3 and then 2 and a half out.

 

I disagree... my own experience tells me that if your dual outs are too big, you'll loose backpressure and low end torque. I experimented with mine and found that 2.25" dual outs is pretty close to a 3" single out and performes good.