I know this has been covered but MPG means nothing without HP and RAR. I am specing a new VNL 860, sometimes more PNW and passes than I like but it is what it is. I’m interested in hearing overall mpg which would cover the variables in weight and flat vs hills as an overall average.
What I am being told is the d13TC is great mpg flat but give it up on the hills, but hell that is any truck
I am looking at the d13tc 455hp 2.47 or 2.64 rar OR D13 500hp 3.08 or 2.93 ratio. Both would be running the overdrive (ATO) transmission. Typically set cruise at 68 to 70 and drive the turbo especially on hills, keeping it around 30psi
D13TC 455hp peak torque hits about 900rpm with max HP at 1300rpm
D13 500hp peak torque at 1100rpm with max HP around 1400
I have a 2015 d13 500hp no overdrive with a million 60 on her and lifetime is 6.7mpg and still have the emission system…but really wondering why since that is the only problems I have had or have. 70mph puts me right under 1500rpm with 22.5 tires.
Any and all input is greatly appreciated.

