RRC Archives

What's your opinion? Any evidence to back it up?

AC! Postmenopausal! 'Nuff said! <-- (hot flash)

Drive a convertible. I drive a 64 Mustang. You should take a ride with me one day girl. Did you see me Saturday? I honked at you.

I prefer having the windows down, unless I have a monster in the back seat who doesn't like her mile long hair whipping around in her eyes and shiz.

snoopdogg, are you hitting on my girlfriend?

On the highway, closed windows decrease air resistance, so run the air conditioner. But in stop-and-go traffic, shutting off the air conditioning and opening the windows can lighten your fuel use. If it's cool enough, use the flow-through ventilation in your car instead of the air conditioning.

Another way to reduce fuel consumption is to think "aerodynamic" and "lightweight". Reduce drag. Remove bicycle and ski racks when not in use. Excess weight also uses more fuel. Remove unnecessary items from inside the vehicle, trunk or truck bed. An extra 100lbs (48 kg) of weight can increase your fuel bill by 2%.

Now, if I only take my own advice....

Running the AC is more fuel efficient above 45-50 mph. Open windows increase the drag coefficient, which is a primary determining factor for how much power is required to attain and maintain any given speed, or the max possible speed. Obviously, the more aerodynamic your vehicle is, the less it becomes a factor (The Ferrari Modena 550 can reach the same top speed with the convertable top up or down, THAT is a "smooth" design).

What most people feel as a "loss of power" with the AC on is correct, but is more an issue of torque (where as top speed relies on power). However, at constant speed, torque is not the issue, power is.

If anyone cares to see(though I don't think anyone will), I can dig out my fluid dynamics book from college and give you the formulas relating power and drag coefficient to velocity. It has been a few years since I worked with the aforementioned formulas, so I don't still have them in memory.

snoopdogg wrote:Drive a convertible. I drive a 64 Mustang. You should take a ride with me one day girl. Did you see me Saturday? I honked at you.

Sorry, snoop, I must have missed you... I was too busy swooning over Loren... *sigh*...

squeezindlemmon and Rain Man, Thanks! That's pretty much what I do-- windows up on the highway, down otherwise (unless I'm riding with Sandy and want to piss her off). Just checking to see what everyone else's thoughts were.

To bad loren was swooning over me! SHABAAM!

I'm 18 months away from having to worry about airconditioning and windows in a car, oh well. Although i do prefer the AC.