A/C vs open window( screened windows?) [ Archive] - GasSavers.org - Helping You Save at the Pump


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Hateful
11-13-2007, 07:03 PM
Just had a thought somewhere between my underside cover and the " Wool tuft testing threads" It seems to be the common opinion that A/C on is better than windows down; at least over 45mph anyway. But what if you made a framed window screen insert to fit your window instead of the window totally opened or the AC on?
I've seen the netting on NASCAR discussed on TV,saying there is an aerodynamic advantage to the nets over the window( in addition to safety).
Not really a seasonable question now, but worth a thought.

Nerds laugh at me
11-13-2007, 07:24 PM
I'm assuming that you mean just having the windows cracked and having it screened off.
Personally, I have thought of having a small NACA shaped scoop on a piece of plastic ( coroplast or whatever ) and having it supported between the window glass and the door. You would just roll down the window a few inches and insert the thing between the edge of the glass and the door frame. A flexible tube ( dryer vent hose ) would channel the air towards you.

It would look just like the setup that they have in NASCAR.

Hateful
11-13-2007, 07:38 PM
I'm assuming that you mean just having the windows cracked and having it screened off.
Personally, I have thought of having a small NACA shaped scoop on a piece of plastic ( coroplast or whatever ) and having it supported between the window glass and the door. You would just roll down the window a few inches and insert the thing between the edge of the glass and the door frame. A flexible tube ( dryer vent hose ) would channel the air towards you.

It would look just like the setup that they have in NASCAR.I hadn't really decided about how much of the window,but your idea sounds good. Maybe in addition to that, have another set up in the back window for the air to exit the window. The curved top of a 2 litter coke bottle might be cut into a nice scoop.

bobski
11-16-2007, 11:38 PM
I'm pretty sure Nascar window netting is there to keep limbs and things from hanging out the window in the event of a crash, not for aerodynamics.

Has anybody actually tested this theory for themselves? I seem to recall mythbusters testing it and finding that having the A/C on consumed more fuel than driving with the windows down. I don't recall their specific test conditions beyond them driving in circles around an oval track for hours on end.

Hateful
11-17-2007, 12:02 AM
you're right that safety is the main purpose,but aerodynamics is considered.The nets didn't always have the wide flat design. As far as AC vs windows down, I've heard that the windows down is better until 45mph. At 45mph windows up and AC is better. I'm just saying that a screen would narrow that difference. Lately I've just been riding with windows up and AC off until I stop at lights,then roll them back up after moving again. I don't mind suffering a little if I can one day get a 500 mile tank.

trebuchet03
11-17-2007, 12:32 AM
In my recent tuft testing... I discovered that cracking the windows open made the tufts on the rear glass "freak out." Which was surprising news to me.... So I'm not so sure if there will be a [measurable] benefit to using a screen/net :/ But that's not to say it's not worth testing :)

Lately I've just been riding with windows up and AC off until I stop at lights,then roll them back up after moving again.
That's what I do :p Summer temps in South Florida are big incentives to use the reflective sun screen while parked :p