An Australian couple has just set a new world record for “hypermiling,” or pushing a car’s boundaries for fuel efficiency. John and Helen Taylor, who have been at this for some time, drove a Volkswagen Passat TDI 1,626 miles on one tank of diesel fuel, setting a record in the U.S.

Into hyperdrive

A select breed of people try to squeeze every last inch of distance from every last drop of fuel. The practice is often referred to “hypermiling,” according to Wired, and people who do it, or “hypermilers,” challenge themselves to see just how many miles per gallon they can achieve.

A new record for the continental United States, according to AutoBlog, has just been set by an Australian couple who have been hypermiling for years. John and Helen Taylor, who run a Shell-sponsored site called Fuel Academy, now hold the Guinness record for overall “Lowest Fuel Consumption” for the continental 48 states, by hitting 84.1 mpg in a Volkswagen Passat SE TDI.

Texas to Virginia on one tank

The Taylors have set Guinness records for mileage before, including this individual record. According to Automobile magazine, they also hold the lowest fuel consumption record for a gas-powered non-hybrid car in the Lower 48, achieving 64.62 mpg in a Chevrolet Cruze Eco.

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Every step of the journey was fastidiously documented from first fill-up, checks of the remaining fuel in the tank and second fill-up, all of which were done in front of witnesses. The car was filled to the brim with 19.3 gallons of ultra-low sulfur diesel, 0.8 gallons more than Volkswagen rates the car for, according to specs on VW’s website. The fuel tank was sealed with a sticker, normal procedure for economy runs.

The Taylors used real-life driving conditions, packing the trunk with 120 pounds of luggage and driving on highways. They also took turns at the wheel, driving about 7 hours per day each.  They started from Houston, Texas on May 3 and finished in Sterling, Va., on May 5. The total distance traveled was 1,621.1 miles, an average of 84.1 miles per gallon.

No modifications

The car was a stock Passat SE TDI, with a six-speed manual transmission, according to Automobile. Typically, the Passat is rated for 43 mpg in highway conditions, meaning the Taylors nearly doubled the car’s potential. They stuck to the 60 mile per hour speed limit, an absolute must for hypermilers, according to Wired.

The Passat is well known for fuel economy. The previous world record for fuel economy was set with a European-specification Passat BlueMotion TDI, with a 1.6-liter engine. That car, according to AutoGuide, went 1,526.6 miles on a tank. Volkswagen’s Passat blog has an entry about the owner of a Auburn, Wash., Volkswagen dealership who averaged 55 mpg while traveling 829 miles, from Auburn to San Francisco, Calif., on one tank.