From Myth Busters:
Annotated Mythbusters: Episode 64: More Myths Revisited
They had a much simpler test setup this time. They had an electronic flowmeter hooked into fuel line of Jamie's pickup. Adam: "For anyone out there that wants to e-mail telling me that we screwed up this test, we have already calibrated this thing, to this car. So it's going to be perfect!" They drove the pickup truck up and down the stretch of 101 around Candlestick and the Cow Palace.
* Tailgate down: 5.2 gallons/hr @ 55mph. 1.2 gallons/hr @ 25.
* Tailgate up: 5.0 gallons/hr @ 55mph. No reading for 25mph given, but tailgate up was once again confirmed as more efficient.
* Hardcover over pickup bed: 5.0 gallons/hr @ 55mph. 1.2 gallons/hr @25mph
* Tailgate mesh: 5% more efficient
* Tailgate removed: about the same as tailgate up and hardcover
Mesh was most efficient by 5%
I'd venture to say the 5th wheel tailgate would yield similar results as the 'mesh tailgate'.
Annotated Mythbusters: Episode 64: More Myths Revisited
They had a much simpler test setup this time. They had an electronic flowmeter hooked into fuel line of Jamie's pickup. Adam: "For anyone out there that wants to e-mail telling me that we screwed up this test, we have already calibrated this thing, to this car. So it's going to be perfect!" They drove the pickup truck up and down the stretch of 101 around Candlestick and the Cow Palace.
* Tailgate down: 5.2 gallons/hr @ 55mph. 1.2 gallons/hr @ 25.
* Tailgate up: 5.0 gallons/hr @ 55mph. No reading for 25mph given, but tailgate up was once again confirmed as more efficient.
* Hardcover over pickup bed: 5.0 gallons/hr @ 55mph. 1.2 gallons/hr @25mph
* Tailgate mesh: 5% more efficient
* Tailgate removed: about the same as tailgate up and hardcover
Mesh was most efficient by 5%
I'd venture to say the 5th wheel tailgate would yield similar results as the 'mesh tailgate'.
