Got a chance to do some testing the last couple days:

Got out on the highway, set the cruise at 72mph for over 130 miles each time and this is what I got. Weird as it is.

open bed tailgate up: 19.7mpg
open bed tailgate removed completely: 18.2mpg
open bed tailgate down: 18.0mpg
open bed tailgate net: 17.8mpg
factory soft bed cover installed (over the rail toolbox that was there for other tests had to be removed): 19.8mpg

Did all this driving between Michigan and Indiana with the truck empty, on VERY flat roads. reset the trip computer a couple times on each test, and verified the mileage at the pump.

Just some information for everyone to use as they wish. I'm pretty bummed about the tailgate net... REALLY like the way it looked, but not worth the trade-off!

 

Those figures verify the results we've seen on a weblink to an experiment done by college students in search of the most aerodynamic configuration for a truck.

Unfortunately, the link no longer works.

http://mars.wnec.edu/~ehaffner/did.htm

 

the engineers design the truck bed to hold a "pillow" of air, then the air flowing over the truck's cab will continue its flow over the bed and over the "pillow". hence making it more aerodynamic. this is what i have heard, and after studying engineering it makes sense. now, my truck on the other hand...well, i think a parachute is more aerodynamic than a 1st gen. but i pull great mileage.

my brother had installed a tailgate net once, it net him worse mileage as well. great scam to make some money, kinda like that rock .....

Pat

 

Those pesky vortices will get you every time.

 

golf ***** have dimples

 

One other thing that happened durring all that highway time is that I must have gotten almost a dozen comments on the CB from semi-truck drivers on how great the open pipe exhaust sounded when I passed them.

Those guys have great taste!

 

So I should leave my truck outside next time there's a hail storm so's I'll get improved MPG?...

 

ain't ya never heard of speed holes?!?!?

 

Maybe you could get it "dimpled" at the next appliance shoot.

~Rob

 

Dave's "Dimple Installer"

 

My jeep got pounded from hail last year.. Basically hit the top and passenger side... now I know why it pulls to the left going down the highway (no dimples on that side ) ...

 

They confirmed this a while back.

 

Thanks for the info.

What was the wind like?

 

And what do I do, I remove the whole bed and put iron on it. That might explain why I don't get consistent higher teens for mpg.