Duramax vs Power Stroke Fuel Economy Tow Test and Drag Race

FishOnOne wrote:

4x4ord wrote:
The problem with doing mileage tests over a short distance like this is that if during the test the Duramax happened to do a DPF regeneration and the Ford didn't the results are meaningless. I think it takes roughly a gallon of fuel to clean the DPF so on a run where only a few gallons of diesel is required the mileage result could be way off.

I thought about that but if a truck did do a regen I think the mpg delta between these two trucks would have been greater. Plus towing this much weight there should have been passive regen working in their favor.

I agree. Towing that much weight under that much load the truck should not have needed an active regen. I think the 3.42 rear end on the GM might have had an effect on mpg here especially if they let the truck do all the shifting.

My 2014 Ram 2500 also has a 3.42 rear and and while it is great for mpg unloaded, it is not so great loaded IF I let the computer do the shifting allowing it to go into 6th. If I lockout 6th and to in 5th(which is still an overdrive gear) then that brings my rpms up to the Cummins recommended rpms of 1,800-2,100 for most efficient towing in the 6.7L. Allowing the the computer to shift into 6th putting me at 1,500 rpm decreases my fuel mileage by about 1-2 mpg depending on the terrain.