Monday, September 30, 2013 5:45:07 PM America/Detroit

Hyperactive Miler

Get 50 mpg -- in your own car

Back in June, when I first wanted to write this article, Michigan gas prices were at an all-time high. Right now, our prices aren’t too far off from those highs. You might want to book mark this page for quick access when gas prices go over $4.00/gallon this year in 2008 here in the States.

The link above is an article about “hypermiling,” the technique of driving to increase your gas mileage. The person being interviewed claims he gets 50 mpg on his 2005 Honda Accord.

“A pedestrian is someone who thought there were a couple of gallons left in the tank.”

Some of the techniques are obvious and boring: drive at (or below) the speed limit; don’t accelerate quickly; keep your tires inflated.

Some, however, are more interesting: draft behind cars; reduce a vehicle’s weight; and don’t slow for on or off-ramps.

That’s right-- practicing your track driving on the street can improve your gas mileage. Who knew?!

I’m trying some of the techniques from this article and other hypermiling websites. I try park so I don’t have to back out; I try not to maintain my speed up a hill (I just keep my throttle position the same); I try not to accelerate hard too often. I also don’t let the engine idle, like when I scrape the ice of windows. I would estimate that I get an extra 1 mpg from these techniques. At 18,000 miles per year, going from 30 mpg to 31 mpg will save me 19.4 gallons per year. At $3/gallon, that’s 14.5 grande frappuccinos.

I’ve also done some informal studies on the effect of an air conditioner on gas mileage. I drove with the windows fully open, with the windows closed and air conditioner on, and with the windows closed last summer in my 2000 Honda Civic (1.6L VTEC). I drove each condition for two fill-ups (at least 9 gallons) on my daily commute to work (one-third freeway, two-third surface streets).

With the windows open, I averaged 31.3 mpg. With the air conditioner, I averaged 30.4 mpg. With the windows closed, I averaged 32.2 mpg. This was hardly a conclusive test, but the trends reinforce traditional thinking. There is almost a 2 mpg advantage to driving with the air conditioner off. Barista, more frappuccinos for everyone!

I tried something similar later in the summer, as I drove our 2005 Subaru Legacy (2.5L turbo) from Michigan to California and back. On this drive, my data was based on highway driving. I averaged 1.8 mpg more with the air conditioner off. [Update: Each run was done with one tankful of gas, but at different times of the day in August 2007. The run with the air conditioner was done in the afternoon.]

This certainly bodes well for deodorant manufacturers.

However, I still have a long way to go if I want to be a card-carrying hypermiler. The highest gas mileage I’ve seen on my Honda is 38 mpg, as we drove on the high plains from Denver to Nebraska when the car was just six months old. I will go against every driving instinct I have and try to beat this gas mileage for at least one fill-up in 2008. Ideally, I want to average at least 40 mpg (that’s 5.6 L/100 km for European readers).

I’m going to need a lot of luck.