Does anybody know what I should expect for performance with removing the muffler? MPG, horsepower, etc?

 

a badass sounding diesel!!!

 

You should prob post this question in the diesel section.

 

moved

 

I've got an 06 5.9 that has 5" straight pipe from the turbo back (no cat - no muf).

Here is what he sounded like running on the dyno a few months back DYNO RUN It is loud there is no question about that. There is a bit of a drone at freeway speeds. But it only bothers me when we have a trailer on the truck. Other than that it just sounds good

There was a slight improvement in HP / TQ over stock

I pulled:
HP Max - 276.4 HP Avg - 236.9
Torque Max - 534.7 Torque Avg - 482

With no other mod's but exhaust

 

those numbers are about right for a stock truck even with the stock exhaust.

 

I just want it to sound like a diesel.
Thanks guys.

 

remove the cat and muffler and throw a set of stacks on it...you cant beat the way mine sounds

 

I want mine to sound like a diesel too, but thanks to the EPA that is not possible without hacking off that huge mess in my exhaust.

 

Mine deffinately sounds like one of the big boys