I'm going to put a bigger exhaust on the new truck I'm picking up today, a 2006 2500.
I was just wondering how much of a difference 4" is compared to 5" performance wise. The only reason I'm thinking of 4" is because I wanted the duals. Like the looks of them and I haven't seen any 5" dual exhaust systems.
So like i said.. just wondering if its better just to go with the 5" or the 4 will do?

 

I have the 5 inch on my 2006. The way I figured it was that with the stock exhaust already being a 4 inch (technically 3.8 inch), i wanted something more for the money I was going spend. Performance wise I haven't noticed any power increase. Maybe a slight decrease in EGT. And they may make a 5 inch dual, however, clearance for the spare tires has gotta be tight...

 

can't help you with the exhaust, but i want some pictures of this!!!
1989 F-250, Inline 6, 5 Speed, 7.56:1 Unimog Axles, Custom Suspenion, Exo Cage, 42" Iroks, OBA, Air Lockers, Hy-Steer

 

If you plan on going over 500hp I'd go with the 5" otherwise 4" is good unless you want the different tone.

 

4" will do fine...do some searching on the threads...it will give you all the info you asked for.