Whats the differences? Especially with gas mileage And I'm talking about the 3rd generation.

 

my buddy has an 06 stock with a 5.9 and mines a 6.7 but he gets like 19mpg especially on the highway were mine only gets about 16 but mine is faster

 

If you have the 6.7, you ought to be getting at least 18 yourself. My dad was using my grandpa's and was running anywhere from 70-75 and getting 22mpg. Where's the difference in power at, low end, mid range. But you did help me out a little. I want a cummins and i'm debating on what engine.

 

biggest difference is all the emissions crap but they can be removed.... typically the 6.7's are running 13-17mpg (HAND calculated) dont rely on the overhead console

My 06 5.9 with 285's and a SMARTY JR on the fuel mileage setting is around 20.2 mpg

Ian

 

that was hand calculated, and it gets 16-17 pulling my 21 ft. bass boat.

 

Also important is that the 6.7 requires the use of ULSD where-as the 5.9L can use LSD or ULSD. Its not really a problem here in the states since ULSD seems to be everywhere now.

 

My '05 2500 Ram diesel 5.9 gets about 19.5 mpg in mixed city/highway driving. I've gotten as high as 23 mpg on the interstate empty. Towing our 5th Wheel camper, I get about 13.8. The guys I've talked to with the 6.7 get about 2 mpg less than me on average.

 

Wheres the power difference at then?

Just saying, you have the right road conditions, my grandpas stock 6.7 will lay rubber, will the 5.9's? If I am running 40 and I floor it, which one will get me to 80 first.