Decrease In Mpg With Ac On

[akewlguy]

I realize my LEXUS gets about 20 MPG.. Then I started to think that I always have the AC on... So what can I expect when the AC is off..? Maybe a mile or two more?

Gas can go over $3 a gallon because I love my LEXUS and it loves premium fuel!

[Lexusfreak]

I realize my LEXUS gets about 20 MPG.. Then I started to think that I always have the AC on... So what can I expect when the AC is off..? Maybe a mile or two more?

Gas can go over $3 a gallon because I love my LEXUS and it loves premium fuel!

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Gotta love a V8 engine! :( You should get about 10 - 15% better fuel economy with the A/C off. Make sure your tire pressure is correct & at the proper air pressure.....that too kills fuel economy. ;) Take out any heavy & unnecessary items out of the trunk & back seat that you might have in the car (not the spare & jack mind you). Every little bit helps. B)

[Dust]

Definitely burns few miles, My AC is always on and I started noticing the difference not too long ago. Your right V8 is V8 but we gotta love it. :)

[SW03ES]

20MPG is not bad at all for a 4.0L V8 in a 13 year old car.

What always amazes me about the LS is how much better the mileage is than the ES even though the ES is lighter and has a smaller engine. I'm lucky to get 18mpg.

[blake918]

I only got >1 mpg better with my a/c off when I did this test...definantly not worth it where I drive around in Louisiana and Mississippi. I love seeing the a/c condensating on my front windows...Lexus makes strong a/c!!

[ED.]

Ddi you see that mythbusters when they were driving that truck around seeing what affected the MPG's? Pretty interesting. Driving with the windows down really affects your gas when on the highway. When it gets cooler out I will turn the ac off. I just cant stand the wind noise. This isnt really relevant to your topic at all and for that I apologize : )

thanks

[wwest]

You can use your A/C in a dramatically more efficient mode and improve your gas mileage. Turn it to max cooling and recirculate (during hot/warm weather ONLY) and then use the blower speed to regulate your comfort level.

This will bypass the remix/reheat mode of the system wherein CHILLED airflow is reheated to avoid discomfort and recirculate will be much like keeping the refrigerator door closed so the milk doesn't go sour.

The net is that the A/C compressor will run a LOT less often.

[flanker271]

The net is that the A/C compressor will run a LOT less often.

I thought the compressor stays on all the time whenever the A/C button is pressed. Are using the Auto button in this case?

[nc211]

Ed, I didn't see that Mythbusters. I'm curious, better or worse MPG with the windows down? I actually do not notice a reduction in my mpg with the ac on. I do however feel the reduction in power though. Can't wait for fall and I can turn that whining thing off!

[bigfatlexusman]

My 94 LS gets 20 in the city and around 28 on the higway , ALOT better than my GS300 which gets around 17/23 :cries: but GOD I LOVE MY CARS ;)

[akewlguy]

Never thought about the window down. I always have my arm out the window.

Okay so I need to pay attention, keep the window up and enjoy the AC. I just accept the fact that each fillup for 400 miles is about 50 bucks.

On the mythbusters did they do anything with the sunroof and AC on? Anything other then window down? I am going to their website. Chow

[wwest]

Windows down or even sunroof only disrupts airflow around car, all that wind noise is turbolence, and increases the Cd.

A/C light on dash only indicates that "you" want the A/C to run, enabled, if you will. The A/C compressor clutch will be engaged when the liquid refrigerant in the reservior drops below a certain level. So the A/C compressor cycles on and off as a function of how fast the cooling capability of the evaporator is being used. Little, or no, airflow through the evaporator vanes and the compressor doesn't cycle very often.

The "system" will automaticaqlly disable the A/C compressor clutch during WOT, engine approaching overheat, evaporator vanes near freezing, inordinately low refrigerant pressure, and OAT at or below freezing, regardless of A/C indicator light status.

[akewlguy]

Yeah they call it parasite drag in the air force. Anything that causes drag on the airframe or in this case the automobile.

I would think the visor (tilt) would not be a big deal. Wide open would obviously be another issue since its more drag.