Has anyone deleted the muffler on their 600 but left the cat on? If so what are your impressions of sound? I want it to sound tough, like the older ones did--like a semi, but dont want it to be ridiculous. What are some of you doing?

 

I've been thinking of doing this exact thing. Interested in any replies.

 

No one has done this? What about just a 4" straightpipe cat delete? (No tests in IL). I don't want the dreaded drone and wife prefers quiet. I am thinking of getting rid of the silencer ring though cuz I gotta hear the turbo. Maybe an intake too. How restrictive are the stock intakes?

 

I did this last week to my new 600/48RE and while it is not as loud as my 03 555/6-Speed it still has the Cummins sound and still may be to loud for some folks.I thought that my 03 was a little to loud under load or WOT but I'm very pleased with the sound of this one with the kitty left on.I hope this helps you guys out in your decision.

 

Did you notice an improved in performance, mileage?

 

I just had 300 miles on the truck when I took the muffler off so it is hard to say.I did take a road trip after and going 150 miles none stop at 72 mph the overhead showed 16.3 so I'm pleased with that.The 300 miles I already had on the truck were 90% in town miles and the overhead showed 13.2.The one thing I have noticed is that I get a soot film on the fender now so I guess the muffler was good for something.

 

From what I've been told and read, the Donaldson 51" muffler seems to be the best sounding muffler on the market.