Exhaust Sound
ENLJones,
The sound difference can be due to the type of muffler and the type of muffler (or lack of) packing material. There are a lot of mufflers that don't have any packing and they will sound "different" on an 03 Cummins. The type of packing will also effect the sound level and type of tone, we use a ceramic blanket that's almost 2 inches thick and a stainless steel inner wrap that's right at 1 inches thick, together they are almost 3 inches total thickness. They are both compressed to fit in a 1 inch space on either side of the muffler for a total of a 2 inch area, and that dampens the "ugly" sounds and lets the "diesel" sounds thru, for a nice deep rumble tone.
Mark
DPPI