Make It Last

By Jerry Garrett

August 15, 2008 6 min read


Hypermilers explore the light and dark side of fuel economy

Jerry Garrett

Creators News Service

What exactly is a hypermiler? Simply put, they are drivers who try to exceed the EPA's fuel economy ratings for their vehicles by modifying their driving habits and vehicle setup.

Hybrid vehicle owners' clubs started the hypermiler craze in recent years by using their cars' real time mileage displays to fine-tune their acceleration and braking techniques. By doing this, owners of hybrid vehicles found they could get well over 100 miles per gallon. Weekend mileage challenges are popular activities for these club members.

A group of automotive journalists once got together to stage a competition for mileage. The winners, the editors of Car and Driver Magazine, averaged 106 mpg for a 100-mile trip in a Honda Insight - a vehicle EPA rated for 66 mpg. However, they felt they could do better. On a second try, they got 121.7 mpg for 147 miles.

Hypermiling is not limited to hybrid vehicles. Just about any vehicle can be driven much more economically than its EPA rating.

Fuel saving tricks used by hypermilers today originated during events such as the cross-country Mobil Economy Run that ran from 1936 until 1968. Mobil participants were known to coast down hills and even push their vehicles to save fuel in hopes of winning a trophy. But fuel was so cheap during the 1960s, the fuel economy runs eventually took a back seat to the horsepower wars and were discontinued.

In its basic form, hypermiling is all about using common sense: replace aggressive and wasteful driving habits such as jackrabbit starts and hard braking with smooth and easy acceleration and braking. Maintain a steady speed, use cruise control and look ahead to anticipate changing road conditions or traffic lights.

Hybrids are all equipped with computer displays which track fuel usage, both moment to moment as well as cumulatively. Watching those displays provides important clues as to which throttle and braking styles yield maximum mileage. Non-hybrid vehicles, especially those manufactured since the mid-1990s, are quite easy to equip with aftermarket gauges that will provide the same sort of information.

Drivers of the Toyota Prius, for example, have found that by easing off the throttle slightly during acceleration, fuel economy shoots up. Accelerating gently up to 35 mph can also allow the Prius' electric engine alone to power the vehicle without any aid from its small gasoline engine. In that mode, the car uses no gas at all. Some tuner shops that specialize in Priuses have figured out ways to even re-program the onboard computer to prolong the vehicle's electric-only mode capabilities.

But hypermiling techniques are not limited to driving style. How motorists maintain their vehicles is also key in reaching optimal fuel economy. Keeping tires properly inflated can improve fuel economy by two to three percent, according to the U.S. Department of Energy.

Using the recommended grade of motor oil is also helpful in improving fuel economy. Motorists should use the grade of motor oil recommended by the manufacturer for their climate.

However, some hypermilers are taking their sport to dangerous levels by doing foolhardy things such as using lower weight oils than recommended. Too light a weight of oil can cause major damage to a vehicle's engine, especially if it used in extreme conditions such as summer heat or winter cold.

They also over-inflate their tires, which can make them more susceptible to road hazard and suspension damage and can result in premature wear to the center portion of the tread. Over-inflation can also cause handling issues due to less tire surface making contact with the road.

Tires should only be inflated to the pressures recommended by the vehicle manufacturer. These are usually listed in the owner's manual or on a door tag. The pressure ranges listed on the sidewall of the tire are an indication of the tire's capability, not the vehicle's.

Dangerous hypermiling techniques include cutting off the vehicle's engine or putting it in neutral to coast on a roadway, drafting larger vehicles, rolling through stop signs and driving at ultra-slow, erratic or unsafe speeds.

Turning the vehicle off is especially unwise because power steering and power brakes then won't work. It may take several seconds to restart the vehicle and restore these functions, leaving a driver unable to react quickly enough to emergencies or changing driving conditions.

Of course, rolling stops, tailgating and such techniques are illegal as well as dangerous.

Saving as much fuel as possible is always a prudent course of action, but it is important to always use safe and sane techniques when trying to facilitate improved economy.

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