Yup, I agree with that. I hardly tried at all and my mileage went way up but I got bored real quick.

 

It's about "money", not about "fun"!
BTW I'm having "fun" when i could achieve something in a more efficient way! :wink:

 

I think we still need to work on the frontal area. Even on the aero's, there is just too much mass hitting the air.

Since overall length is already maxed, the solutions are few, but what about a retractable spoiler that could be extended out beyond the grille, when you are on the freeway at speeds over say 50 mph? The wing could slice the oncoming air, and steer it up over the trailer, though to do this, it would have to extend beyond the bumper about 5 feet.

Instead of the wall of air hitting the grille, it would rise up and over the truck, greatly reducing drag. This and a boat tail trailer would slice thru the air pretty well.

I see the drag co-efficient as the biggest problem to mpg. But am not an engineer.