SRT10 Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
829 Posts
Discussion Starter #1
I found this article about the drag created by the bed of trucks and how the position of the tailgate affects the air flow. I thought it was quite interesting. Here are a few blurbs with a link to the entire article from Motor magazine.


"Recently, Kevin Cooper of the National Research Council of Canada published a paper through the SAE which proved that removing the tailgate from a pickup truck not only doesn't help gas mileage, it actually makes it worse... Removing the tailgate looks like it should re-duce drag, but a number of processes, including wind tunnel testing and computer modeling, proved it doesn't."

"Several methods-including CFD flow analysis-were used to reach the conclusions presented in Kevin Cooper's SAE paper. Using a variety of popular make full-size trucks and a 75-mph wind speed, the vehicles were tested in a wind tunnel with the tailgate up, down and removed. One had a mesh gate made of duct tape. One had an adjustable tonneau cover that could cover various portions of the truck bed. The wind tunnel balance-measured all six components of aerodynamic force and moment. Drag coefficients (Cd) for the trucks were normalized so the focus could be kept on box aerodynamics. All the measurements showed the same basic results - a small increase in drag with the tailgate down and a larger increase with the tailgate off. These measurements were made with the vehicle directly aligned with the stream of air.

Another interesting result was that lowering or removing the tailgate caused a larger increase in drag on 61/2-ft. boxes than on 8-ft. boxes. Installing the mesh gate was shown to yield the worst results of all. In one example, the Cd increased from .48 to .53 with the mesh gate in place of the solid tailgate.

What does work is a tonneau cover. Interestingly, a partial 20-in. cover placed nearest to the tailgate did 88% as well as a full tonneau cover. On an 8-ft. box, the estimate is that the improvement in fuel economy with a full tonneau could be 1.35 mpg, or a saving of 243 gallons over 100,000 miles of driving. Conversely, the same vehicle without the cover and with a mesh tailgate got 1.28 mpg worse mileage than a vehicle with the tailgate up and no cover."

Link to entire article
 

·
Registered
Joined
·
599 Posts
Good Stuff!
 

·
Registered
Joined
·
301 Posts
I've heard that a pocket of air pressure is created in the bed of the truck with the tailgate up. This is suppose to be helpful. When you lower the tailgate, it's supposedly creates more drag and you get worst mpg. I have tonneaus on all my trucks though and that seems to help a little bit. What the heck. It's just money anyway and I'll drive just like I do now at $1.79 a gallon or $2.50 a gallon. It doesn't matter. Just have to eat one less cheeseburger I guess. :cool:
 
1 - 4 of 4 Posts
Top