Poor Fuel Mileage

My 12.7l put 518hp to the dyno rollers, 1650 torque. I do quite a few different things. But short haul with a hopper 40% of the year. Over 80k hopper and have to idle to load, and deliver line moves fast enough to not be worth shutting engine down. 5.0-6.5 mpg. That mostly changes with temps.

Other than that, I dont idle. I warm up to 140. Anytime I can shut it off I do. Pryo drops under 300, key off.


Drive like there is a egg under pedal. Try not to make boost in low side of trans.

 

Just because you have the power dont mean you need to use it. Sounds like you have a well running set up.

 

My general feeling on this one is don’t go crazy with big changes. Sounds like you’ve gone through a lot of what creates problems. If truck is running right, which it seems like it is. Make small adjustments then monitor. Basically if you pick up a .6mpg gain then your right in the wheelhouse of your setup running local. That kinda fluctuation can vary quarter to quarter with temperature and filter changes. Don’t beat yourself up too hard on this one. Even a dose of kerosene to thin fuel when colder out will give you that mpg boost.

 

They make clear kerosene for house heaters but it’s normally only sold in 5 gallon jugs, but you might be able to find a local oil company that sells it in bigger containers.

 

It will do better on summer fuel, at least Mine always have, more btu's in it.