Gas mileage tricks or myths ?

[JohnnyO]

Wouldnt it be interesting to see a wind tunnel test with the tailgate up, down and covered ? Preferably with some coloring dust so you could see whats actually going on ? I dont have one on the Ranger yet but I have one on my 1979 ElCamino and it doesn't take a genius to look out the rear mirror and see the wind buffeting the cover.. So it would seem to be a good idea.

Mythbusters tried that with two Chevy trucks and didn't see any difference but they were 4 door short beds and the race track limited them to 45 mph.
One school of thought is that air packs into an uncovered bed and the rest of the air passes over it.
My personal experience with my old 3.0 Ranger that didn't have enough power to get out of its own way was that it held speed on the highway better after I got a tonneau.

 

[AllanD]

An electric fan rather then the one mounted to the water pump. That saves mileage.

Not that ANYONE other than a company that makes electric fans has ever been able to prove.

at highway speeds the fan really doesn't cause any drag because it's nearly "windmilling" in moving air, the slippage in the fan-clutch is just
enough to prevent the fan from truely windmilling and being forced
to turn.

It's most like a "flight idle" power setting on a propeller driven airplane,
when the prop is turned just fast enough so it doesn't try to do the
aircraft equivilent of "engine braking".

when accelerating it takes power to turn it, but at highway
you aren't doing much accelerating.

MOST vehicles with electric fans have them because it's damned
inconvenient to mount a mechanical fan on a transverse engine.

The one thing E-fans do better is move air when the engine is idling in
traffic jams.

 

[ngzcaz]

I like mythbusters but sometimes they fall off the mark. The tonneau cover to my way of thinking and in actual useage would be to test it on the interstates.
If there would be a difference it should show up there. I wouldnt expect any measureable difference at 45 mph.
Obviously the length of the bed should make a difference in the calculations.
The manufacturers of the tonneau covers claim a difference. Maybe I'll give one of them a call and ask for their test results, ect

 

[Trollbait]

Wouldnt it be interesting to see a wind tunnel test with the tailgate up, down and covered ? Preferably with some coloring dust so you could see whats actually going on ? I dont have one on the Ranger yet but I have one on my 1979 ElCamino and it doesn't take a genius to look out the rear mirror and see the wind buffeting the cover.. So it would seem to be a good idea.

They didn't use any colored dust, but they did gate up, down, air gate, bed fully covered, and bed partially covered.
http://ecow.engr.wisc.edu/cgi-bin/getbig/me/363/ghandhi1/pickup.pdf
Leave the gate was the conclusion. Cover the bed if you want to improve the aerodynamics. Even just covering the back 20 inches reduced drag.

The electric fan may help by allowing the engine to warm up quicker. To get a noticable improvement, you likely will have to block the radiator in conjuction.

 

[philS]

I'm in the midst of running a tailgate-down test for the next few tanks of gas (with no other changes). I will post the results when I'm done.

For now, I get 27-28 mpg on my Gen 1 Ranger -- short cab, long bed, no tonneau cover, 2wd, stock tire, 5-speed and 2.9

 

[AllanD]

The things that DO improve mileage are proper front end alignment
(particularly Toe) and tire inflation pressure.

For mileage the ONLY consideration in tires is rolling resistance,
so set the pressure to maximum as shown on the tire sidewall.

this is not for traction or ride quality, but to make the tire HARD,
hard tires roll more easily.

Anything less than the maximum pressure costs you fuel.

AD