This is more of a rant than anything, but here goes. Now that I'm into the winter gas, my gas mileage has been dropping as expected. It's down about 10%, which oddly enough matches up to the gas pump signs stating "May contain up to 10% ethanol". Some of the gas stations put the "to prevent fuel line freeze up" underneath. I never worried about that until it got to -30 and less than a 1/4 tank, but I must be an idiot because it used to be that 2oz was good for a tank.

I don't understand the rationale; If I have to use 10% more fuel to get where I'm going, I'm putting the same amount of emissions into the atmosphere and I'm using the same amount of gasoline as I would without the ethanol. So what the hell? Who came up with this idea? Maybe the oil companies are making a buck off it, but I don't know what it costs to produce ethanol. But my opinion is it's a waste of time, energy, land and food production.

I must be getting old because I don't understand these kind of things that go on in the world. I need a beer, the proper use of ethanol.

It's just politically arranged, corporate welfare for Archer Daniels Midland. We're all just stuck in the middle.

That's for damn sure. We are exporting more petroleum now than we have in two decades. Drilling is at an all time peak, and the corn supplement does nothing but prematurely age the materials in engines. Doesn't save one plug nickel. To convert the corn to ethanol, it wouldn't surprise me one bit if they are using natural gas for the conversion. Tell me that makes sense....

If they want to supplement corn, start allowing more diesel engines into this country for passenger vehicles, SUV's and light trucks!! Make them all burn corn oil....

Any chance that it's nothing more than the cold weather causing the drop in fuel mileage? Cold weather affects everything...grease in the wheel bearings, power steering fluid, driveline greases and oils, air pressure in the tires, etc

I never understood why so many people are convinced that there's this mysterious mixture of "winter gas" which causes a drop in fuel economy when very simply the drop in fuel economy during the winter months is directly attributed to the cold weather and how it affects the fluids and lubrication in particular.

It's all political with no benefit to the taxpayer or the green earth. It actually costs more to produce ethanol than gasoline:

The Real Cost of Ethanol - Business Exchange

HOW MANY SENATORS DOES IT TAKE TO SCREW A TAXPAYER? (Featured Article) « The Burning Platform

The EPA has become an activist organization ... it has out grown it's usefulness, as have many other federal programs.

Has nothing to do with ethanol in winter as ethanol is all year around. I posted this about a month ago so here is why you get worse gas milage in winter.




"Winter" Gas Explained

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Many threads have shown up in the last month or so on gas milage drop as we approach winter. Here are a few articles that explain what winter gas is and why we need it. I learned most of this stuff in college but have forgotten most of it.

One:
Here's the poop: As specified by state law, reformulated winter gas contains any number of lighter, lower-boiling-point hydrocarbons (butane, propane, etc.) that just so happen to have an excellent octane value. Added to this may be any number of oxygen-bearing ether compounds (MTBE, ETBE, ethanol) that improve emissions and also have a relatively high octane blending value.

So what's all the bad hype for? Price, for one thing "It's actually more expensive to make reformulated winter gas than normal, summer fuel, ' says Thomas Hart. Lower fuel economy is another concern.

"The oxygen-bearing compounds displace fuel components, so it takes more fuel to get the job done. Normal gasoline has a stoichiometric ratio of 14.7:1, reformulated winter fuel runs between 14.3 and 14.4:1," says Mitch Markusich.

And the complaints about poor performance? Mitch says, "When people ***** about the fuel, it's not really the fuel's fault. The weather is largely responsible; after all, it is winter. Low cranking voltage in the battery, increased oil viscosity, atmospheric condensation in underground fuel tanks and so forth."

The bottom line is that when it's cold, winter gas seems to be the hot ticket for performance enthusiasts. Not only is the dense winter air good for horsepower, but the higher oxygen content and octane value of winter gas make the pot sweeter And as for fuel economy and price? When did that ever get in the way of having a good time behind the wheel? It s just too bad we have to deal with all that snow and ice".

Two:
A Primer on Gasoline Blending
Gasoline is composed of many different hydrocarbons. Crude oil enters a refinery, and is processed through various units before being blended into gasoline. A refinery may have a fluid catalytic cracker (FCC), an alkylate unit, and a reformer, each of which produces gasoline blending components. Alkylate gasoline, for example, is valuable because it has a very high octane, and can be used to produce high-octane (and higher value) blends. Light straight run gasoline is the least processed stream. It is cheap to produce, but it has a low octane. The person specifying the gasoline blends has to mix all of the components together to meet the product specifications.

There are two very important (although not the only) specifications that need to be met for each gasoline blend. The gasoline needs to have the proper octane, and it needs to have the proper Reid vapor pressure, or RVP. While the octane of a particular grade is constant throughout the year, the RVP spec changes as cooler weather sets in.

The RVP is the vapor pressure of the gasoline blend when the temperature is 100 degrees F. Normal atmospheric pressure varies, but is usually around 14.7 lbs per square inch (psi). Atmospheric pressure is caused by the weight of the air over our heads. If a liquid has a vapor pressure of greater than local atmospheric pressure, that liquid boils. For example, when you heat a pot of water, the vapor pressure increases until it reaches atmospheric pressure. At that point, the water begins to boil.

In the summer, when temperatures can exceed 100 degrees F in many locations, it is important that the RVP of gasoline is well below 14.7. Otherwise, it can pressure up your gas tanks and gas cans, and it can boil in open containers. Gas that is boiled off ends up in the atmosphere, and contributes to air pollution. Therefore, the EPA has declared that summer gasoline blends may not exceed 7.8 psi in some locations, and 9.0 psi in others.

A typical summer gasoline blend might consist of 40% FCC gas, 25% straight run gas, 15% alkylate, 18% reformate, and 2% butane. The RVP of the gasoline blend depends on how much of each component is in the blend, and what the RVP is of each component. Butane is a relatively inexpensive ingredient in gasoline, but it has the highest vapor pressure at around 52 psi.

In a gasoline blend, each component contributes a fraction to the overall RVP. In the case of butane, if there is 10% butane in the blend, it will contribute around 5.2 psi (10% of 52 psi) to the overall blend. (In reality, it is slightly more complicated than this, because some components interact with each other which can affect the expected RVP). This means that in the summer, the butane fraction must be very low in the gasoline, or the overall RVP of the blend will be too high. That is the primary difference between winter and summer gasoline blends.

Why Prices Fall in the Fall
Winter gasoline blends are phased in as the weather gets cooler. September 15th is the date of the first increase in RVP, and in some areas the allowed RVP eventually increases to 15 psi. This has two implications for gasoline prices every fall. First, as noted, butane is a cheaper blending component than most of the other ingredients. That makes fall and winter gasoline cheaper to produce. But the increased ability to add butane also means that gasoline supplies effectively increase as the RVP requirement increases. Not only that, but this all takes place after summer driving season, when demand typically falls off. On the other hand, refiners usually draw down inventories of summer gasoline leading up to September 15th to make room for the changeover, and this can lead to vulnerabilities should hurricanes come into play (as they did this year).

These factors normally combine each year to reduce gasoline prices in the fall (even in non-election years). The RVP is stepped back down to summer levels starting in the spring, and this usually causes prices to increase. But lest you think of buying cheap winter gasoline and storing it until spring or summer, remember that it will pressure up as the weather heats up, and the contained butane will start to vaporize out of the mix.

And that's why gasoline prices generally fall back in the fall, and spring forward in the spring.