Fact or Fiction? does leaving the tailgate down while driving empty give you better milage? anyone?

 

Fiction.

This was debunked by a major University.

When the tailgate is up it creates a high pressure area behind the cab which causes the air to go up and over the bed & tailgate.

 

http://www.carjunky.com/news/newtext/411.shtml

chrck this guy out what do you think?

 

Studies have proved that, tail gate off = loss of MPG, tail gate down (IF you have a long bed) may offer some improvment. Short bed-forget it. Webbed tail gates=much worse. There is a link to the study somewhere. Been posted here before.

 

I remember hearing an engineer from Ford state that they actually design the truck to create a high pressure area in the bed of the truck with the gate up like Monsta stated. It causes the flow of air over the cab to lift over the bed and tailgate. Open the gate or remove it and you get a low pressure area in the back of the cab causing drag.

 

Motor Trend, Car and Driver, a bunch of mags all have done this test. Surprisingly the tailgate up is the most aerodynamic. Think about it; a big car company is under immense pressure from the fed, to lower CAFE (corporate average fuel economy), which takes every car in the line, averages it's EPA mileage and that's what the company's numbers are. Trucks are the biggest offenders of course, big horsepower, big weight, big tow capacity, etc. So if Ford, could gain mileage without a tailgate, they would. Billions of dollars are spent yearly to lower CAFE a half mile per gallon. That's why claims from guys who have tornado air twirlers, in-line magnetic fuel molecule aligners, special gas additives (not counting synthetic oil, they are proven to work) and all that hocus pocus is nothing but profit in someone's hands. Everytime I turn on the radio I hear an ad for Cortismack, or some BS, it's on every radio station, on every TV channel, in every magazine, it's unrelenting. So, one of a couple things; it's a great product and there are huge numbers of people buying it consistently, or, and probably the truth, there is ZERO manufacturing costs, because you basically don't get anything and 90% of costs in those bogus weight loss products is the advertising. There aint no magic, no-how, nowhere, (although David Blaine, the street magician puts on a pretty convincing imitation) it takes X amount of fuel to push X amount of weight through X amount of air at X amount of air. Engineers live and die working on this, a tailgate seems simple and easy, like in 'why didn't they think of this' ? They did, believe me. Ken

 

Hmmm... even with the side windows closed, there is enough pressure in my bed to blow leaves through the rear split-window right onto the front seat (SC).

I have a bed height cap, when it's on is the only time I see that magical 16MPG - I have a supercab short-bed... it drops to 14.5 or so without the cap on...

 

I meant CAB-height - as in level with the top of the cab. Duh...

 

If you could manage the air under, and over your truck, you could lose the low pressure area behind your truck, that will suck leaves into your cab, and raise your efficiency a little more. Check out the new Ferrari 430, the underbody tray is gaudy as heck, but works to help airflow, just like rear deck spoilers do, peace, Ken

 

Well when asked a few co-workers looked at me like i was nutz, som say they can feel the drag of the tailgate up, othes think o.k. yeah it's possible the engineers are right with the air bubble concept, but i would have to say the best argument to keeping the gate up was this........"why would i drive around with my gate down? if sone one rear ends me then not only do i have to replace the gate but most likely the side quaters as well plus maybe some frame damage! and all for a few mpg and $ scew that!"

once i heard this all the engineering in the world didn't matter lol. toss this one back to the simplest things are sometines the best.

 

If engineering for the best mpg was our goal, would we be driving Ford trucks ? I don't think so either, good point on the tailgate. Ken

 

After reading his so-called "facts" it looks to me like a forum for dis-information. That's the beauty of the internet.

 

Some of the info on that sight was just common sense, accelerate and stop slowly, tire pressure, etc. But some of them were a ways out there, how to go 50 miles in a car that gets 20 mpg on a single gallon ??? Ken

 

Doesn't that violate the law of "Conservation of energy" ? Spending fuel to accelerate to 20MPH and then losing that momentum to friction and drag doesn't sound like it would save anything, but then again, it might work in certain cars, especially those fuel consumption marathons he's talking about.

One thing about that article - notice it mentions lockup convertors and 4-speed auto's as better than 3-speed autos without lockup - sounds like it was written 20 years ago.

When was the last time you saw ANYTHING without an overdrive and a lockup converter?

But I wholeheartedly agree with the "drag chute" affect of pickup truck boxes - I can easily increase my MPG by 1 or 1.5 by putting my cab height cap on it for long trips. And, I have a short-bed (theoretically less of a drag chute)...

 

Caps yes, tonneaus yes, but tail gate down, the manufacturers at least say no.

4 speed autos w/lock-up are passe' now. 6 speed autos, 7 speed autos, where do we stop ? Will there be 8-10-12 spped autos in 10 years ? Or will the CVT take over ? I don't think the CVT will be the savior, it's a metal chain between two metal expanding/contracting pulleys, Ken