More on hypermiling — even automatics do it
August 19th, 2008, 2:55 pm · Post a Comment · posted by Le Templar
(Original photo at www.scangauge.com)
On Aug. 10, the Tribune Perspective section featured an article I wrote about hypermiling – a style of driving motor vehicles that’s intended to greatly boost your miles per gallon. As a concept, hypermiling is rather controversial. Some techniques are common sense, but others run counter to long-ingrained American driving habits, and some are viewed as downright dangerous. One technique in the last category that’s called a forced auto stopped provoked strong reaction from readers who left voice messages questioning my sanity and wrote letters asking me to stay far away from where they drive.
(As background: a forced auto stop refers to switching the engine ignition off while you are bringing the vehicle to a stop at a traffic light or a parking space. You do this by shifting the transmission into neutral, turning the ignition key off and then to position II, and relying on a combination of braking and inertia to halt the vehicle. The danger is a vehicle loses power steering wheel and power brakes when the engine is off, and if the key is left in the wrong position, the steering wheel can completely lock up.)
A couple of questions came up that deserve some answers. First of all, two of my friends were surprised I didn’t mention that my 2003 Honda Civic is a five-speed manual transmission. Their assumption is a forced auto stop is easier to perform with a stick-shift because the driver uses the clutch to move in and out of neutral all of the time. Most drivers who use automatic transmissions almost never shift into neutral, just going from park to drive or reverse instead.
I double-checked with my sources before I wrote my column to confirm that many hypermilers use automatic vehicles, and the basic theory behind forced auto stops applies to both types of automobiles. But the individual steps for carrying out the technique will be different from vehicle to vehicle depending on each model’s design.
My trainer, Louis Hudgin, said you should always test a vehicle in a safe location before working with forced auto stops. Using an empty parking lot, for example, a driver needs to see how the steering wheel and brakes respond without the engine turned off. The mechanical design of some vehicles won’t allow for forced auto stops or other advanced hypermiling techniques.
One Tribune reader called to point out something he considered ironic. Also on Aug. 10 in the Tribune Carfinder section, talk show mechanics Tom and Ray Magliozzi (Click and Clack on National Public Radio), wrote about the severe damage you can do to an automatic transmission if you miss neutral and accidentally shift into reverse while the car is moving forward. Ray Magliozzi criticized people who shift into neutral while coasting at high speeds to save gas (which is not the same thing as forced auto stops).
A wrong shift into reverse certainly is possible if you’re not paying attention (primarily for automatic transmissions, it’s far more difficult to accidentally hit reverse with my stick-shift). That’s why many hypermilers say they focus much harder on what they do behind the wheel than the average driver. Many of them refuse to use cell phones or to eat or even to listen to radios, avoiding any possible distractions.
But the Magliozzi brothers also pointed out that many late-model cars now have a feature that prevents shifting into reverse while moving forward, something to look for whether or not you hypermile.
The other question I received was about the ScanGauge, the device that plugs into your vehicle’s engine computer and gives an immediate, on-going estimate of miles per gallon. Mesa manufacturer Linear-Logic sells the device for about $170. ScanGauges must be popular, as the devices are going for about $160 on eBay.
