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Discussion Starter · #1 ·
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Race with tailgate up or down or removed, Tonneau cover on or off? Answer inside
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Ever wonder what the aerodynamics are of removing the tailgate or the tonneau cover? Leaving them on is better? others say removing it.
What is the answer?

well I found this intersting article Quite interesting.



quote:
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"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."
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Discussion Starter · #3 ·
Suavy said:
Very interesting! Must be a lawyer?

Suavy :twisted:
:smt026
 

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Maybe it's more physiological than anything else,
but come to a big event / track day, and you'll see pretty much
EVERYONE'S tail gate off when flying down the 1320 (mine included)

I got to believe WITH a tonneau cover (soft or hard) the reason
I and OTHERS remove it, is strictly for Weight Reduction,
and I don't think it would increase the drag ATT ALL (with a cover as said)
I have a soft cover.

Without a Cover, "and for gas consumption",
I agree 100% with the article and find it interesting

GOOD READING Wikdsv, THANKS :smt023
 

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Good article. That is why I love my tonneau cover....not that I see any increased mileage with it! I figure reduce the drag so I can go faster!! :D

Charlie
 

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