Tuesday, August 7, 2007

Hot Gas Myth - BUSTED!

On August 2, I filled up my gas tank with "10.873" gallons of regular
unleaded gasoline. It was 95 degrees outside. The heat of the day.

Recent media reports want you to believe that because of complex
physical properties inherent to gasoline, I may have actually put in
much, much less than 10.873 gallons into my gas tank. These reports say
that gasoline expands as it warms up, and your fuel economy could
suffer, AS MUCH AS 30%, if you fill up your tank with "hot gas" instead
of gasoline that's been stored at closer to room temperature.

The news said this is such an obvious problem that our friends in Hawaii
have attachments to their gas pumps to adjust for the "hot gas
phenomenon."

This is a bunch of baloney.

I travelled over 400 miles on that tank of gas that was pumped in 95
degree heat, and achieved fuel economy of 38.55 miles per gallon, which
is more than one mile per gallon better than my 2007 average, and more
than two miles per gallon better than my overall average fuel economy.

Had this "hot gas" really held less power than regular gas, if it shrank
in my gas tank, my fuel economy should have been hurt. In fact, a 30%
decrease in my fuel economy would bring it down to 27 mpg. Certainly
I'd have noticed that. Indeed, I notice as little as a 10% difference
in my fuel economy from tank to tank.

Once I had a tank of gas that served my 10% lower mileage. It was a
tank in February, in the dead cold of winter. That was likely due to
driving in the cold, and the engine had to work harder to get warmed up
and more efficient.

The facts based on the data I have kept since I purchased this Corolla
tend to indicate that summer fuel economy is a little better than winter
fuel economy.

As this tank shows, "hot gas" is really just "hot air." It does not
have an affect on fuel economy, and it is not a rip off.

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