Peterbilt 378. 3.5mpg. What can I do?

I’m a local float, dump and live bottom hauler with a 1998 3406E Ford.

18 speed, 4:11 gears, 1,600 rpms at 63 mph on 11r22.5 tires.

average is 4.5 mpg (us) for most of last year. 4 mpg with lots of idling, 5.5 mpg for highway.

 

I run 40% of the year hopper bottom heavy. 2 lane 55 mph speed limit in the buckeye short haul. 13 speed 3.58. 5.3 to 6.5. With a yearly average of 6.2. Pull spread the rest of the year with side kit. Weather is more responsible for my change. I have seen 8 plus loaded light with covered wagon.

 

Jamespmack:

your truck is definitely better than mine on fuel.

I’ll see how my company freightliner does once it’s back together from Inframe.

That’s a 2005 C15 ACERT. 18 speed, 4.11 gears, 63 mph at 1,600 as well. (It does go 67 mph but it sucks fuel at that speed)

575 hp, 2,050 tq.

The freightliner definitely does better on fuel than any of the other trucks we have when pulling a loaded B-train. Slightly less when pulling light loads than the others. Not sure why.

 

I dont see it as a difference from brand to brand so much. More unlaiden weight, proper maintance, gearing, and disciplined driving. If you haul over 80k,better get paid enough because fuel milage is a second thought. And under 60mph aerodynamics mean nothing. Work on your idle time too. Under 300 on pyro. Shut it off.