Hello from Indiana,
I'm Jeremy Moen. I have a '01 Dodge 3500 dually with a 5 spd and Cummins. Has a few power mods and I guess efficiency mods to some degree.
I've been looking through this site a bit and am pretty amped to read through all the info here. I did not know this hypermiling and stuff existed. I find myself thinking about fuel economy quite a bit, especially standing at the diesel pump.
I live close to where I work, so aero isn't of prime importance in day to day commute. I get about 18 mpg going back and forth to work usually, a tank of diesel lasts a month or more. (2nd and 3rd gear, 20-30mph mostly). Aero IS important to me when I use the truck what I bought it for - to tow my 26ft enclosed car trailer to road courses around the mid west.
The Dodge gets about 22-23 mpg (overall hand calculated average) when I'm on interstates around 65 - 70 mph. That gets knocked down to about 12.5-13 pulling the trailer (empty or with a car in it).
Needless to say, I'd love to find some aero mods to help streamline my rig and get a couple more mpg. That would make a big difference in the cost of a weekend of fun.
I actually tried making a wing out of some leftover plywood I had around, but the results were not real conclusive. Some weather on the way back I think skewed it. But now that I found this site, I'll surely get some good feedback from you experts out there.
So for now I'll just keep reading and learning.
A big thanks to all of you that invest your own time and money in experiments etc., and are willing to share your experience and knowledge on a site like this to benefit others!!