Is your gas mileage decreasing

[Anthony Whitesell]

IT HAS NOTHING TO DO WITH THE ETHANOL (atleast at the 10% that's in the fuel around here). You're air conditioner has been running all winter. The A/C runs when the defroster is on. I drive 30,000 miles a year, use 15-17 gallons a week. I always get the best gas mileage in the spring and the fall. I drive a 2004 Nissan Altima and get 32-33 mpg in the spring and fall and 28-29 in the summer and the winter. Hummm...the same in the summer and the winter? The air conditioner is only on in the winter and the summer.

I tried a few experiments in January.
1. I physically disconnected the air conditioner wires so it would not run. Yep. 28.6 last week, 32.4 this week.
2. Re-connected the A/C and ran it like normal. Back to 28.6
3. With the A/C re-connected, I froze my butt off and never turned on the heat. Try that for twelve hours (that's how long a tank of gas lasts me on the clock) in New England in January. Back to 32
4. Ran the defroster the entire week. Made sure never to turn off the fan or change it out of defrost. How low can you go? Try 27.2mpg.

Try it for yourself...

I now try to minimize my defroster usage to minimize the amount the A/C runs. What's worse is that some cars A/C doesn't turn off after the defroster has been turned on until the car is turned off. That would be the Nissan Altima. The '02 Chevy S-10 and '02 Cavalier both only run the A/C when the defroster runs. The A/C turns off when not in defrost (unlike the Altima)

[Chris Padilla]

My "miles per gallon" is directly related to the direction and speed of the blowing wind; I bike to/from work.

[Chad Voller]

IT HAS NOTHING TO DO WITH THE ETHANOL (atleast at the 10% that's in the fuel around here). You're air conditioner has been running all winter. The A/C runs when the defroster is on. I drive 30,000 miles a year, use 15-17 gallons a week. I always get the best gas mileage in the spring and the fall. I drive a 2004 Nissan Altima and get 32-33 mpg in the spring and fall and 28-29 in the summer and the winter. Hummm...the same in the summer and the winter? The air conditioner is only on in the winter and the summer.

I'm not 100% postive on this, but the AC is on when you turn defrost on so the moisture is pulled out of the air being blown onto the window. I'm just lucky I park in a heated garage, as I rarely need to use it. I think in MN, the mix is always 8-10%, so I can't blame my milage on that, unless they recently added more ethanol? The extreme low temperatures drop tire pressure when parked outside at work, and I work real close to home, so the engine doesn't warm up all the way for efficient driving. These affect me the most. Of course if I ran my defrost more, it will kill my milage even more. In-town driving in these conditions I see about 19MPG in a 01 Grand Am, and about 22 in the summer. Highway wise I get 27-29 both summer and winter, just depends on how much faster than legal I feel like driving.

[Anthony Whitesell]

That's exactly why the defroster is on. While my AC was disconnected the windows fogged horribly until the car was toasty warm and the window was hot enough not to condense the water vapor.

On short stints I would expect to see a small drop in mileage due to the @#$% computers in the cars. In the winter, the starting mixture is richer than in the summer due to the temperature. I would double check to make sure that you never turn to the defroster during the week and see what happens with your mileage.

[Roy Hatch]

Forgive me if someone has already mentioned the subject of "Top Tier" gasoline. It's interesting to see how the list has grown from when I first saw it. http://www.toptiergas.com/retailers.html.

I still buy the cheap stuff.

Roy

[Thomas Canfield]

Back in the '50s, the LPG (Butane & Propane) dealer in my rural South Texas town was driving a pickup converted to propane. He was always ready to stop and show how clean the oil was with the clean burning fuel. He was reluctant to talk about the lack of power and that it only had about 50 to 60% of the power and towing capacity of a gasoline engine and the mpg were also way down. The price of propane was about half the price of gasoline then so that was not as big and issue.

Using corn for fuel sure looks to be questionable with all the problems, feed issues for livestock, and food related issues. Sure glad that BIG Brother is watching out for us poor individuals like us don't have to make those decisions. I do plan to keep driving a plain gasoline engine as long as possible.

[Rob Russell]

BTW, those of us who drive hybrids also have our worst mileage during the coldest weather as battery technologies available today are much less efficient when they are cold. I take about a 3 MPG hit on my Highlander at this time of year, although I can't complain too much about just under 25 mpg in a mid-sized SUV.

Jim,

The biggest reason hybrids take a hit in the winter has nothing to do with the batteries - it's truly the temperature.

Sort of an obvious statement, but hybrids save gas by shutting off the engine - the battery is just a way to power the car while the engine is off. The engine has to be warm enough to shutoff and still come back on instantly when needed. In the winter, the cold temps will cool off the engine faster, so it has to cycle back on more to keep up to operating temps.

FYI, my brother's Highlander Hybrid experiences the same thing as you.

Rob

[James Jaragosky]

It has always been my belief that the gas burned during the combustion cycle never produced its entire energy potential to start with, Are you sure that you are taking energy a loss to the drive train with E90?

I would think that this has been studied to death by someone.
probably cost plenty of tax dollars to do it too.

[Cliff Rohrabacher]

Electric will be the way to go.

Right now you can run a car on 15 or 20 lead acid deep cycle batteries - that last a very long time.
A pickup with 20 or so Batteries built under the bed would be a worthy thing.

Tesla uses 7000 little lithium batteries but they only last 3 years and lose 20% capacity each year.

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