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My sales rep told me that the AC on the smart is not directly driven by the engine, but instead has an electric motor to drive the pump and blower. He also stated that running with the AC on is not going to change the gas mileage of my smart one iota.

When I turn the AC on, I hear/feel something dragging down. Is that the "massive" 90 amp alternator working overtime to run the AC? Seems like something starts dragging the car/engine down a little when the AC kicks on.
 

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scan guage shows a 5-7 mpg decrease when I turn on the AC... very consistent... anyone else looked into this?
 

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So far, I have not noticed any difference with my gas mileage. It has been consistent with 39 MPG and I have had the A/C on a few times. Someone in AZ would know better...
 

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My sales rep told me that the AC on the smart is not directly driven by the engine, but instead has an electric motor to drive the pump and blower.
Wow! Who teaches these salesman all this BS...
Looks like a multi-rib drive belt driving the A/C pump, just like any other car.
 

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No Free Lunch with Entropy

Running the A/C or even the headlights takes energy. If it had no effect on the gas milage, then that would be a bad design as you would then be paying the penalty when they are off for the extra load / drag / friction being put on the engine needlessly.:)

High School Physics: 3 laws of thermodynamics (paraphrased): you can't get something for nothing, you can't win, and you have to lose. Seems to also apply to car sales :D
 

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I really don't think running the lights is going to impact MPG. The AC compressor is going to tax the engine directly though, and therefore WOULD impact MPG. The Alternator is going to be running regardless, and I don't think the draw from the lights is going to increase the impact of the already running alternator. I guess if all electrical systems drawing more than a few amps were OFF, no radio, nothing then the alternator might disengage and monitor battery power and charging. But, that doesn't seem too probable on this puppy
 

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I really don't think running the lights is going to impact MPG. The AC compressor is going to tax the engine directly though, and therefore WOULD impact MPG. The Alternator is going to be running regardless, and I don't think the draw from the lights is going to increase the impact of the already running alternator. I guess if all electrical systems drawing more than a few amps were OFF, no radio, nothing then the alternator might disengage and monitor battery power and charging. But, that doesn't seem too probable on this puppy
Running lights may not make a measurable difference in mileage. But I can tell you that my non smart car, on a dyno, gives up a couple of horsepower with the dashboard fan on vs being off. It costs something to run anything.


AC obviously uses more power than headlights. Headlights use more power than the dash fan.

Oh, and before all you hypermilers take this the next extreme, the .005 mpg you save by driving with the lights off at dusk, will be more than offset by the insurance deductable for the fender bender you have when the other guy can't see you.;)
 

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sure

Sure, but I mean if the fan is ON already (or any other AC load device) the alternator is going to be running. I don't think putting on an additional current draw at that time is going to increase the load of the alternator, is it?
 

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gas milage impacts

Sure, but I mean if the fan is ON already (or any other AC load device) the alternator is going to be running. I don't think putting on an additional current draw at that time is going to increase the load of the alternator, is it?
From a technical standpoint, all items using electricity, no matter how small, will have an impact on how hard the engine has to work, thus impacting mpg. However, a well-designed engine/electrical system takes much of the normal drag into account, and you won't see any really measurable reduction in your mileage. Large draws, such as A/C, however, are not "normal", and will reduce your mileage noticably.
If you are one of those people that insist that you don't have a stereo worth talking about until you can hear it in the next county, that, too, will reduce performance, but you may make up for it in prize money (BTW - check the sponsors are those events - if they are sponsored by the makers of hearing aids, you'll know what's up).
But that kind of thing aside, don't run around without headlights, neglecting to use turn signals, not running windshield wipers, etc., thinking you will save money. As previously noted, the cost of the tickets and accidents will more than off-set any savings.
There was also a study out in the 70's, when the first gas crunch hit (different story, same impact to the consumer), that running your A/C was more cost-effective than opening your windows. I have checked that in several of my vehicles, and I can attest that that may be true on large cars with lots of windows, but not all cars.

Cheers!
 

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My sales rep told me that the AC on the smart is not directly driven by the engine, but instead has an electric motor to drive the pump and blower. He also stated that running with the AC on is not going to change the gas mileage of my smart one iota.

When I turn the AC on, I hear/feel something dragging down. Is that the "massive" 90 amp alternator working overtime to run the AC? Seems like something starts dragging the car/engine down a little when the AC kicks on.
Another misinformed uneducated or possibly smokin' crack salesman. The compressor runs off the engine drive belt like almost every other c`ar does. I have noticed it effects my gas mileage at least 2-4 mpg when in use
 

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AC/blower on effects my engine

I don't know how to describe this accurately....

When I drive with the AC and/or air blower off, I move through the 5 gears smoothly. With the AC/blower on, I get coughing, hicccuping and it feels almost as if the engine will die (especially in 1st and 2nd gear).

Is my Smart broken?

It has less than 100 miles on it and is 3 days old.

Thanks for any feedback and advice.

Holly
 

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I don't know how to describe this accurately....

When I drive with the AC and/or air blower off, I move through the 5 gears smoothly. With the AC/blower on, I get coughing, hicccuping and it feels almost as if the engine will die (especially in 1st and 2nd gear).

Is my Smart broken?

It has less than 100 miles on it and is 3 days old.

Thanks for any feedback and advice.

Holly
Holly, Don't worry the smart gets better with miles. When you hit 800-1000 miles you will think it's a different car(power, shifting etc all improve).

As far as mileage and running the A/C.. I see a real world 1.5 - 2 mpg reduction with the A/C on 100% of the time and a slight slow down in acceleration. Nothing to wory about.
 

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Holly, Don't worry the smart gets better with miles. When you hit 800-1000 miles you will think it's a different car(power, shifting etc all improve).

As far as mileage and running the A/C.. I see a real world 1.5 - 2 mpg reduction with the A/C on 100% of the time and a slight slow down in acceleration. Nothing to wory about.

Shoot. I'm at 800 miles now and I was thinking I was getting better at shifting. :) I am guessing that riding around at highway speed with the top down isn't helping my mileage either, but it sure is fun.
 

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My sales rep told me that the AC on the smart is not directly driven by the engine, but instead has an electric motor to drive the pump and blower. He also stated that running with the AC on is not going to change the gas mileage of my smart one iota.

When I turn the AC on, I hear/feel something dragging down. Is that the "massive" 90 amp alternator working overtime to run the AC? Seems like something starts dragging the car/engine down a little when the AC kicks on.
My salesmen told me the EXACT same thing so I put my hands on his sholders and pulled him real close so he could not get away while I raised my knee into his crotch three or for times. He still did not look convinced so I laid him on the pavement and stood on his neck for a minute while I maced him a little. I thought I was done but he started mumbling somethign about "tire protection" so I went back and kicked him a few times and he calmed down after that.

I only recommend this course of action in the case of extreme salesman stupidity. You can usually avoid dealing with it by not asking them any questions and just walking away if their lips start to move.:D:rolleyes::p

Oh, yeah. My scangague shows an almost instantanious 4mpg drop when I turn on the AC and none of the AC settign seem to make any difference. Hi, medioum, low, recirculate... It all seems to result in a 4 mpg drop.
 

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Oh, yeah. My scangague shows an almost instantanious 4mpg drop when I turn on the AC and none of the AC settign seem to make any difference. Hi, medioum, low, recirculate... It all seems to result in a 4 mpg drop.
That seems reasonable to me. My driving style has not changed from my previous car to the smart. I am getting about 34 to 37 in a combination of ~40/60 highway and city driving AND the air is ALWAYS on. Am willing to sacrifice a few MPG's for comfort and quiet and no windand dirt from open windows.
 

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ac and hiccups

Holly, Don't worry the smart gets better with miles. When you hit 800-1000 miles you will think it's a different car(power, shifting etc all improve).

As far as mileage and running the A/C.. I see a real world 1.5 - 2 mpg reduction with the A/C on 100% of the time and a slight slow down in acceleration. Nothing to wory about.
Thanks for the reassurance! I do love this car, but all the plastic makes it feels a bit fragile. I guess I haven't had time to build up trust in it yet.

Glad to hear the hiccuping and hesitation is typical.

Holly
 

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One reason I feel like my Pure is a little quicker is the weight. My only option was the alarm so my Smart weights a good bit less than one with A/C, power windows, power steering, even the Passion 'glass' roof is heavier I bet. All this adds up and affects the cars power AND MPG. All these goodies take a toll on the 70 hp available.
 

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I would have to say that " hiccups and hesitation " is NOT typical and ain't a good thing. The engine will bog down a bit with the A/C compressor applying increased load at the accessory belt. Ya are using more power for " stuff " hence some of the available power is not so available for motive force to make the vehicle go down the road.
The engine should NOT hiccup nor hesitate. Will the gearbox shift a tad bit differently and will acceleration be just slightly different than with the compressor freewheeling?
Yep. Drastic or nasty ? NOPE .

just a thunk
 

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One reason I feel like my Pure is a little quicker is the weight. My only option was the alarm so my Smart weights a good bit less than one with A/C, power windows, power steering, even the Passion 'glass' roof is heavier I bet. All this adds up and affects the cars power AND MPG. All these goodies take a toll on the 70 hp available.
I'm sure the pure weights a bit less then passion or cabriolet.
About the glass roof on the passion models being heavier I can't say I know the exact weight difference betwean them but the passion has a thin polycarbonet roof, same type of material used on most prescription glasses, very light compared to tempered glass.
 

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Well this makes me feel better

Down here in FLA, I am already driving with the A/C on constantly more or less. It is good to know I can expect to realize some better gas mileage in the fall when things are cooler.
 
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