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Made a 150 mile trip to a school reunion this past Friday. Left late at night and had windows down and no ac on. had 5mph crosswind and driving 65/70 on highway, got 37.7 mpg. On return trip Sunday 100 outside temp. had air on all the way and went to 30 mpg. Has anyone else experienced such a drastic drop when AC used?
 

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See other post on same topic. Such large mileage variations usually mean that there were headwinds going one direction... even light winds can cause high MPG variations. Hills could be another factor.
 

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Have been running the A/C constantly on my visit to Texas; mpg has suffered but there are other factors - wind, hills, city driving, using 89 octane that all certainly could account for the drop.
 

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Made a 150 mile trip to a school reunion this past Friday. Left late at night and had windows down and no ac on. had 5mph crosswind and driving 65/70 on highway, got 37.7 mpg. On return trip Sunday 100 outside temp. had air on all the way and went to 30 mpg. Has anyone else experienced such a drastic drop when AC used?
How are you measuring the MPG? With a ScanGuage?
 

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I went on an 800 mile roundtrip to L.A. Going down there I averaged 46 mpg. Coming back I got 33 mpg. I filled up with premium at a gas station off the Buttonwillow exit on I-5 and immediately noticed a drop in power. It seemed that batch of gas was not what it was cracked up to be.

So the quality of any gas you refilled with on the return trip also may have played a role in your decreased mpg.
 

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I have taken hits from the AC as well. However as was suggested by someone else on the forum I took a Jumbo sunshade and cut it down to cover the roof in the car and it made a drastic difference in the temp in the car.
 

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42, 40, 38 when you drive this car its not all about mpg

I went on an 800 mile roundtrip to L.A. Going down there I averaged 46 mpg. Coming back I got 33 mpg. I filled up with premium at a gas station off the Buttonwillow exit on I-5 and immediately noticed a drop in power. It seemed that batch of gas was not what it was cracked up to be.

So the quality of any gas you refilled with on the return trip also may have played a role in your decreased mpg.

just wondering about your trip you said..DOWN to L.A. and then back (up) I would guess...
I was just wondering if we have a mpg change by driving North (less) or South (more) Just need to get a driver going east west to see if the car is pulling better numbers driving Down South

We have a plan drive from Va to Niagara Falls so we will see, but I drive a Cab and some times run the a/c at the same time to top is open...

and yes my wife says Im crazy to open the top when temp is over 90 and the damn a/c is atleast cooling my feet :rolleyes:
 

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MPG with A/C

See other post on same topic. Such large mileage variations usually mean that there were headwinds going one direction... even light winds can cause high MPG variations. Hills could be another factor.
I concur. MPG loss from A/C is small. Windows down has a significant aero drag, which also affects mileage, actually slightly MORE than A/C.

To save gas with A/C: Once you are comfortable, bump up the temp control one click at a time (68, 70, 72, 74, 76, etc.) until you are still OK, but it does not feel like you are in a refrigerator. You would be amazed how many customer's cars are on full cold and they don't even know about saving fuel by setting it a bit warmer.
 

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just wondering about your trip you said..DOWN to L.A. and then back (up) I would guess...
I was just wondering if we have a mpg change by driving North (less) or South (more) Just need to get a driver going east west to see if the car is pulling better numbers driving Down South

We have a plan drive from Va to Niagara Falls so we will see, but I drive a Cab and some times run the a/c at the same time to top is open...

and yes my wife says Im crazy to open the top when temp is over 90 and the damn a/c is atleast cooling my feet :rolleyes:
More info: I went down to L.A. from Sacramento. Trust me, there was very little difference in the ambient temperature between the two cities. Elevation is also essentially the same. Even though I had to go through the hilly Grapevine on the way down, I also had to go through it on the way back up to Sacramento, so there should have been a neutral impact from elevation changes.
 

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Doesn't surprise me that your gas mileage was so drastically affected by air-conditioning.

These Smarts are not your father's (original) Volkswagons.

Yes, they do share a relatively underpowered engine, but they differ dramatically in gross weight.

Gone are the days of lightweight economy cars that could be powered (with air conditioning) by a small engine.

Our Smarts have all the 'advantages' of modern cars - all of which add weight: full electronics and servos (door locks, windows, convertable tops), ABS (sensors, wiring), emission controls (sensors, catalytic converters), safety (belts, air bags, sensors), fuel injection (electronics, sensors, injectors) etc, etc, etc.

Our 1000cc triples can barely manage the car as it is. Throw in the heavy taxation of a compressor and... well it's no wonder the Smart throws up its hands in despair!

Once the Koreans and Japanese begin to sell micro cars (or two seater city cars) in the US, and as economical forms of transportation, Daimler-Mercedes will have to seriously consider their marketing strategy: Econo-box (lightweight, no frills, exceptional gas mileage), or something else.

I look forward to other micro cars being sold here - and especially the stripped-down models like the good-old-days!

Even the most basic econobox offers better protection than my motorcycle! (Besides, if I were ascairt, I wouldn't be driving a Smart or riding an RE Bullet.)

Matt
 

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I thought Arizonans were the only ones swealtering in the heat. :eek: I haven't gone through my first tank of gas yet. However, at 110 degrees I'm sure my MPG will suffer a bit.
 

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Yeah I was reading about this. Surprising that having the windows down effects MPG so much. Pickup trucks have the same effect with their tailgate. Aerodynamics are very important :)

Mythbusters did a test on the window and pickup tailgate topics... I believe they determined that a pickup is shaped for optimum wind tunnel performance with the tailgate up. Anyone that drops their tailgate to save gas actually loses benefit of an air pocket in the truck bed. I'm not the authority on this, of course, but that's what I remember from the episode.
 
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