Hey...it's been awhile since I posted. Maybe thats a good thing. Anyway I took a quick turnaround trip yesterday of about 300 miles and as I was filling up I thought why don,t I check my mileage. It has probably been 3+ years since I did so. Original owner, 96 3500 dually, 410 gears, 4x4, and has had bigger/better/faster parts on the cummins. You get the picture. Well driving average of 80 mph I ended up getting exactly 13 mpg. How does this look considering speed, gearing, etc.?? I am also running 305/75/16 Hankook ATM rubber.
Just some thoughts please. Thanks

 

At 80 MPH on a 4WD dually?

13 MPG is AMAZING.

Don't touch a thing, better yet run a tank at 65 MPH and let us know what you get.

 

OK..thanks Pat I will do so and let you know.
Mike

 

Best I ever saw on my 96 auto 4x4 with 3:54 was 21...that was flat ground interstate cruise set at 65 around town I averaged 14 to 15 at 80 mph mileage dropped off considerably...

 

The Cummins B makes max torque (in stock form) at about 1,600 rpm. I don't know what that would be with 4.11 gears, but in my '95 with 3.55 gears it's 55 mph. I get GREAT mileage at 55, somewhere over 27 mpg last time I checked. When you go faster not only does the engine need more fuel to make torque, but wind resistance is much increased. Ok, I rarely drive 55 on the Interstates, but on 2-lane blacktop I sure do.