Pleasant surprise
I pulled my Jayco about 150 miles or so on Sunday and back the 150 miles this afternoon. I don't know how accurate the onboard mileage computers are but mine said that I was getting a little over 12 ...
Forum Discussion
LIKE2BUILD wrote:
Funny thing I've noticed on my '14 Ram with 6.7L Cummins.....I get better fuel mileage (at least on the dream-o-meter) running 80MPH vs 70MPH. This is running empty, not towing.....I would NOT tow my trailer that fast.
I know that bucks traditional thought, but I have a hypothesis as to why. At 80 MPH the engine is running a little under 1800 RPM and at 70MPH it's about 1500RPM. The specs on the engine show that peak torque(800 lb-ft) is made at 1700 RPM. See specs at Cumminshub.com. So, what I might guess is at that point of peak torque the engine is getting the most bang per quantity of fuel and running at a fairly high efficiency. I could be completely way off base here, but at least it's a rambling thought.
KJ
According to your theory, and assuming that you have a six speed, you should get the best mileage of all at 70mph in fifth gear. Lower speed for less wind resistance plus higher rpm's.
I think what you are seeing is maybe a glitch in the lie-o-meter programming or an error in your readings.
