Odd aerodynamics?

[AmishMike]

Okay, am I the only one who seemingly gets BETTER mileage with the windows down, or the top off, or RTT on, or the rack mounted with crap hanging off of it?
I swear anything that I do to disrupt the original aerodynamics actually improves the mpg.
I'm talking about normal highway driving 65-75 mph. Same 150 mile drive same elapsed time, etc.. I'm at 27K on the truck and have noticed this since day one, and just thought that I was nuts.

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[kevman65]

It's hard to make the aerodynamics of a rolling brick any worse.......

 

[bd100]

Our minivan is pretty aerodynamic and yet its highway mpg is only a little better than our JT with highway tires and stock suspension. Comparable engines. Tires, lifts, and gears really hit hard.

 

[Jason Oliver]

Okay, am I the only one who seemingly gets BETTER mileage with the windows down, or the top off, or RTT on, or the rack mounted with crap hanging off of it?
I swear anything that I do to disrupt the original aerodynamics actually improves the mpg.
I'm talking about normal highway driving 65-75 mph. Same 150 mile drive same elapsed time, etc.. I'm at 27K on the truck and have noticed this since day one, and just thought that I was nuts.

Yes.

 

[Lunentucker]

 

[redriderjf87]

Maybe it's like dimples on a golf ball and induces turbulence sooner or something. Higher Reynolds number blah blah blah...

Sorry that was my attempt to get an ROI on what little I remember from Fluids class..

 

[Dartboy]

I’ve noticed a pretty consistent 1/2mpg drop driving with the soft top open.

i was tempted to post a similar thread about turbulence- seems smoother airflow with the rear headrests down when the rear window is out

 

[DocMike]

I may have found a color I prefer over Gobi....

My mileage changes for no rhyme or reason. Seems like it gets better with longer trips. At this point, I just drive it.

 

[Lunentucker]

That would be a cool color!

 

[Lunentucker]

 

[JohnFinx]

I get better mileage when I drive with a lead foot, and worse with the tops off. I noticed no difference windows up or down, but the rare occasion I have the windows up the A/C is on, so that may make it a wash.

 

[Rockabillyroy]

Our minivan is pretty aerodynamic and yet its highway mpg is only a little better than our JT with highway tires and stock suspension. Comparable engines. Tires, lifts, and gears really hit hard.

our minivan gets twice the mpg of the JT. You romping on that mini? hahaha...

 

[Free2roam]

You forgot the brick upright with airflow going through the holes

 

[ShadowsPapa]

Okay, am I the only one who seemingly gets BETTER mileage with the windows down, or the top off, or RTT on, or the rack mounted with crap hanging off of it?
I swear anything that I do to disrupt the original aerodynamics actually improves the mpg.
I'm talking about normal highway driving 65-75 mph. Same 150 mile drive same elapsed time, etc.. I'm at 27K on the truck and have noticed this since day one, and just thought that I was nuts.

Yes.

Panels out - mpg drops.
Roof off - mpg drops.
Doors off- mpg drops.
Stuff stacked in the back and cover open - mpg drops.
Windows open - mpg drops.
Anything at all that I do drops mpg.
Took off steel bumper, put plastic bumper and reinstalled the closure panel on top of bumper, etc. - mpg picked up by an easy 1+

I'm talking observing this truck over a period of 30 months and 26,000 miles......... any change away from stock, mpg drops.
But doesn't that make total sense?

Had a 90 Camaro - T-tops off, mpg dropped. Windows open, mpg dropped.........

Oh, before I forget - deduct 10 points from Slytherin for using the term aerodynamics in a post about Jeeps.

 

[Dan in Pasadena]

It's why I have THIS sticker on my rear window.

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