[wjbell]

I have a 2001 Dodge Ram 2500 with the cummins diesel and I'm trying to get better mileage. Right now it gets about 18mpg at 70mph and 16 in town. This is with the winter diesel fuel that I think have additives that make it get less mpg. In the summer I get 19 hwy 16 city. If I slow down to 60-65 I can probably get 20. It has a 4" exhaust, open air filter and a programmer.

So I've heard that 60% of your engines power at higher speeds is being used just to fight wind drag. So I'm trying to find ways to reduce that.

My truck has a rack and side boxes. It's my work truck and I have to keep them otherwise I'd pull those off for starters. But I'm thinking maybe the boxes help a little. The create more of a flat side down the whole length of the truck. So instead of a large drag area behind the cab, maybe it keeps a majority of the air flowing down the side of the truck.. I don't know.

Another thing is the tailgate up or down debate. From what I've heard, with the tailgate closed wind pressure creates a bubble in the bed and new air coming over the top of the cab hits this bubble and it almost acts like a bed cover. I don't know about that either.

So then the wind exits at the back of the vehicle. And with my boxes it creates a huge square abrupt end to the truck that I'm sure makes a huge amount of drag. So I was wondering about a tailgate that was in a 45 degree position, like a wing.This might allow wind to have a continuous flow over the cab, down into the bed and out. This would also change the big blocky back and maybe the air coming through the bed would meet with the air coming around the outside of the truck and help push each other straight back instead of making a big drag point.

I don't know, I'm new to this and want to get some opinions of what I suggested, and also some suggestion of what I could do to help this truck aerodynamically.

Here are a couple pictures of my truck and the tailgate idea.

Thanks for any help on this.

I can't post images or links yet but if you copy these two links you can see the pics

belletc.net/truck/truck1.jpg

belletc.net/truck/truck2.jpg