Air conditioning verses horse power

[dirtsquirt]

question??? Does anyone know how much horse power is eaten up with air conditioning. I know drag racer do not use A/C or Alternators, and most go to electric fans to prevent horse power loss, But how much of a difference is there?

 

[AllanD]

When you aren't actually running the A/C it takes NO power to "turn" it.

And BTW, even if you switch it on it turns itself OFF at WOT.

And actually many drag racers DO run alternators, the idea that an
alternator takes much power is illusion/dilusion becaus unless you do
each run with a freshly charged battery the voltage provided to things
like your fuel pump and more importantly your ignition system will fall off
and even a freshly charged 12volt battery won't operate some things
correctly, because they are REALLY designed to operate at 14.2Volts.

as for electrical water pumps, electric fans and such they are only
of benefit for a VERY short time....on a daily driver? No.

If you wanna know what works on a street vehicle don't look at drag racers
Look instead at ROAD racers.

AD

 

[strvger]

i remember a study being done quite some time ago aobut fuel cost and hp loss of using the ac. it seems to be a wash...
using the ac does use some hp, but that is offset by better aerodynamics due to all the windows being rolled up and the outside air flowing more smoothly over the car body.
just driving with the windows down and no ac saves about the same hp as it looses by the increased drag caused by the disruptive air flow over the open windows.

and i'm pretty sure we've all heard the test done on pickups with the tail gate down vs. the tail gate up for fuel economy...
tail gate up wins as it creates a sort of "air bubble" in the bed that causes air to flow more smoothly/aerodynamically over and around the open bed.
tail gate down is less efficient as it allows the air to swirl all around in the bed and then under the rear of the truck thus increasing drag.

hope this helps.

 

[feellnfroggy]

I lost 5 mpg on the highway with my expedition using a/c. It is a drag on the motor and does cost some. Just depends on what a/c is worth to you whether or not its really a loss.

 

[Tractorman]

I lost 5 mpg on the highway with my expedition using a/c. It is a drag on the motor and does cost some. Just depends on what a/c is worth to you whether or not its really a loss.

No you didn't. There's a million other factors that could have affected that.

 

[Nhaz]

I watched this test on mythbusters. Exact same amounts of fuel in the exact same vehicles one with a/c and one without a/c. The one with A/C not only beat the one without A/C it beat it by several extra times around the track.

It was the aerodynamics of leaving the windows open or closed. they didn't repeat the test with the windows open that i can recall.

I would have =>

 

[4x4junkie]

Should be around 3-4HP when the compressor is engaged.

 

[dirtsquirt]

Thanks guy's. My Ac belt broke, and i noticed a tad more pep in the old girl, And as i do not use AC at all, i may just leave it that way for a bit and see what happens,

As for the racing guy's i know. all 1/4 mile runner's

 

[feellnfroggy]

No you didn't. There's a million other factors that could have affected that.

Who the hell are you? You show up here and with your second post call me a liar? Or at teh very least call me an idiot? I know enough to check controlled factors versus variables. I lived in florida, flatland, summer temps, (consistently 90+ degrees on dry albeit humid days). Three trips same routes, same vehicle weights as I was by myself. (including fuel amounts)

All that aside, I know how to divide my mileage by my fuel capacity which at the least says I lost 5 mpg due to my a/c unit. There is no variable you can offer that can account for a 5mpg loss. Any variable you have, wind speed, tire pressure, etc. at the most will account for 1/2-1.5 mpg.

There are times when I am wrong with a post, and there are times when I have called someone wrong. However it was situations that are provable or have already been verified by reliable sources. I DONT tell anyone "they are wrong" unless I can prove it. Especially with fuel mileage, you shouldn't either.

AllanD, Wicked, and a few other have a reputation around here that they can say what they want and I will eat it up. You however have two posts and nothing to prove you know anything about my vehicle or what you are talking about.

That said, welcome to the site, I truly hope you enjoy it and don't let my mild berating discourage you. You will enjoy it here. Have one on me.

 

[press 1 for english]

I lost 5 mpg on the highway with my expedition using a/c. It is a drag on the motor and does cost some. Just depends on what a/c is worth to you whether or not its really a loss.

You lost 5 mpg by using A/C????? That's horse pukkey, you have other issues. I live in Florida too and I lose 1 mpg with my duratec 2.3, being you have a 5.4 in your Expedition the loss of mpg should be negligible......1 mpg at the most. The more HP the vehicle has, the smaller the effect of A/C on fuel mileage. I don't know you from Adam, but it makes absolutely no sense.
I have a 96 Ford F150 Supercab with a torquey 300 cid 6 and I lose less than 1 mpg with the A/C on........19 down to 18.5.

 

[feellnfroggy]

You lost 5 mpg by using A/C????? That's horse pukkey, you have other issues. I live in Florida too and I lose 1 mpg with my duratec 2.3, being you have a 5.4 in your Expedition the loss of mpg should be negligible......1 mpg at the most. The more HP the vehicle has, the smaller the effect of A/C on fuel mileage. I don't know you from Adam, but it makes absolutely no sense.
I have a 96 Ford F150 Supercab with a torquey 300 cid 6 and I lose less than 1 mpg with the A/C on........19 down to 18.5.

4 cyl will lose alot less. My expedition weighs a whole helluva lot more than your so any pull on the motor is intensified. My expe never got over 20 and that was at 55 mpg on the higway with windows up and nothing running and tires 5psi over. The same trip with same cicumstances only with air on I get 15 mpg. Its been double checked. When I run down the higway at 70 instead of 55 I dont get over 16 mpg. The bigger truck with 125k miles, it loses gas mileage real easy. The 17 ft trailer I pulled to knoxville recently I got 11 MPG.

What is it with peckerheads thinking I dont know what I am talking about tonight? I guess I dont know my own truck and should go back to eatin my bowl of stupid each day, that way I dont misinform you people.

 

[Tractorman]

Who the hell are you? You show up here and with your second post call me a liar? Or at teh very least call me an idiot? I know enough to check controlled factors versus variables. I lived in florida, flatland, summer temps, (consistently 90+ degrees on dry albeit humid days). Three trips same routes, same vehicle weights as I was by myself. (including fuel amounts)

All that aside, I know how to divide my mileage by my fuel capacity which at the least says I lost 5 mpg due to my a/c unit. There is no variable you can offer that can account for a 5mpg loss. Any variable you have, wind speed, tire pressure, etc. at the most will account for 1/2-1.5 mpg.

There are times when I am wrong with a post, and there are times when I have called someone wrong. However it was situations that are provable or have already been verified by reliable sources. I DONT tell anyone "they are wrong" unless I can prove it. Especially with fuel mileage, you shouldn't either.

AllanD, Wicked, and a few other have a reputation around here that they can say what they want and I will eat it up. You however have two posts and nothing to prove you know anything about my vehicle or what you are talking about.

That said, welcome to the site, I truly hope you enjoy it and don't let my mild berating discourage you. You will enjoy it here. Have one on me.

Yes, because I don't have a 1000 posts on a Ranger site means I'm stupid.

The AC did not cause you to lose 5MPG. Maybe it contributed a little bit, but not 5MPG worth. I would bet a bad tank of gas, screwy pump reading, different traffic, all play a bigger factor.

I didn't call you an idiot, but if the shoe fits, wear it. Just because I don't keep log books on YOUR trucks doesn't mean I don't know whats going to happen.

Have a nice day!

 

[Tractorman]

4 cyl will lose alot less. My expedition weighs a whole helluva lot more than your so any pull on the motor is intensified. My expe never got over 20 and that was at 55 mpg on the higway with windows up and nothing running and tires 5psi over. The same trip with same cicumstances only with air on I get 15 mpg. Its been double checked. When I run down the higway at 70 instead of 55 I dont get over 16 mpg. The bigger truck with 125k miles, it loses gas mileage real easy. The 17 ft trailer I pulled to knoxville recently I got 11 MPG.

What is it with peckerheads thinking I dont know what I am talking about tonight? I guess I dont know my own truck and should go back to eatin my bowl of stupid each day, that way I dont misinform you people.

o yea, your math doesn't make sense. Not over 20 without it on, then 15 with it on. That's less than five in my book. But I only have 3 post now, so I must be stupid.

 

[feellnfroggy]

o yea, your math doesn't make sense. Not over 20 without it on, then 15 with it on. That's less than five in my book. But I only have 3 post now, so I must be stupid.

im sorry, your right 15+5 is not 20.


Its an expedition, the gas doesnt sit in it long enough to be bad gas. Never had a single problem withthe fuel pump or the fuel readings. And the traffic, call it what you want but 55 with the cruise set, I was the traffic and didnt have to slow down or speed up for anyone. (everyone shooting around me at 70+)

Maybe, just maybe, I'm right. Maybe it is possible for me to have experienced what I said I did.

Your post count has nothing to do with your smarts, it has alot to do with common courtesy. When your the new guy, you dont start out by running down the knowledge of people who have been around a while and proven their knowledge. Before you go and get your panties in a wad, Im not saying you dont know vehicles either. I am saying that perhaps you should read a little, get to know some people, throw out some reliable info and contribute more than 2 posts, before you start throwing accusations of ignorance at other people.


15+5=20 I checked with the calculator.

 

[Mac]

I would doubt it running the AC that has caused that much of a drop in mileage, he's probable doing the math and everything else the same way. Probably some sensor or other problem not realated to the AC being on or off.
Dave