ATS

This may be a dumb question but I remember from my other cars..

Does turing off the AC give the car more power? I remember from older cars that with the AC on the HP of the car went down..

Thanks.

bmms8

i think it might add a little power, but i dont think its noticeable. i believe the car will just have to work a little harder, like rev harder, but the worst thing is gas mileage. in the E, we use AC because we cant really feel a difference, but in my personal car, i never turn on the A/C even if its 80+ just because it wastes to much gas, and makes my engine work noticably harder. same thing goes with windows unless at low speeds. GL

saffrontiger

I think that using your AC is not going to make a huge difference with gas mileage compared to windows down. The drag created at highway speeds effectively negates the savings on using your AC. Besides, why be uncomfortable in a fine vehicle like your MB.

DWP

The "windows down vs. A/C off" issue came up a few months ago on the NPR show "Car Talk." I don't exactly recall how the brothers came down on the issue, but it was something like: windows down-A/C off saves gas in slow driving, but takes more gas in highway driving.

On a slightly related issue, does the A/C compressor clutch automatically disengage the compressor when the driver depresses the accelerator enough, like in a forced downshift?

bmms8

yea, i do keep my A/C on with the benz because usually our family is riding, so we have to put it on but i remember on top gear 2-3 weeks ago, clarkson or whatever his name is drove a A8 diesel i believe 500 miles on one tank. he was driving and he said that the A/C supposedly uses up 10% more gas! and windows down was 5%? im not to sure though, but i do agree with saff because on the highway, it creates much more lag, my friend told me that over 45 mph, its better to use A/C, but i dont know how true that is.

Nevada Jack

In Las Vegas...windows up, A/C on April thru October...gas milage is secondary...

saffrontiger

Yeah. I hear your pain. Try Dallas from May-Sept. Right now 100 degree days are the norm. Gotta say, the summer veting feature is excellent and i use it all the time especially bc i park my car outside at work. Normal to be 140 degrees plus inside.

Nevada Jack

Guess I had better RTFM and find out about that "summer veting" feature

Oslo

I never turn off my A/C, neither in summer nor in winter (+30/-30 C.)

Ducman

LOL,yah,here in Cali 80 degrees is way to hot !!!

Nevada Jack

80 degrees...that's a cool day here and we even may need the heater

ATS

What I am thinking about is on a day when you don't need AC, I guess there is an advantage to turning it off to save gas.

The reason I want to know is off the line. Stopped at a light on takeoff, will there be an increase in torque or speed off the line?

Thanks.

DWP

That goes back to the question of whether the A/C compressor automatically disengages on full-throttle acceleration (or kickdown). If it does, you don't have to manually turn off the A/C. Logically, anything that uses power that would otherwise go to the rear wheels will decrease gas mileage and acceleration to some degree.

kort677

you're driving a 60k car and you're worried about losing a mile a gallon mpg? give it a rest!

bmms8

he also said that he wants to know off the line.

ats, off the line, if you are going to use a lot of power, or floor it, turn everything off, like the A/C and windows. those will considerably slow you down. GL

Mortenstein

...but if you already pay $499 a month for the car, saving $0.02 a week would almost be a McD cheeseburger at the end of the month... I mean could be handy if there is some month left at the end of money

And just imagine - you not just save big $$$ you also lose some weight - and save the money you would spend on sauna. I never realized that saving money is THAT easy. By a simple press of a button you drive faster, save money and lose weight. Maybe we can get a patent for this multifuncional button.

HELL ONA HARLEY

Hell, I'd be suprised if we were not getting better gas milage by getting sucked down the highway the way that "turbo prop" fan under the hood we all have in these E's spin...

ATS

Kort677.. I never said anything about being "worried" about gas milage. Reread the question...

MBE55AMG

Hmm, interesting question. I doubt you'll notice any significant performance ups, but I'm sure giving the engine some rest also helps as well. I keep my A/C low when I drive, about three bars. And I do somewhat believe it helps the fuel economy.