You’re not alone. These big, four-door cars traditionally have V-6s, with choice of optional V-8s.

But in the interest of fuel economy, Ford is turning tradition on its head.

For 2013, the automaker’s full-size and attractively restyled Taurus includes an optional, turbocharged, EcoBoost four cylinder that capably and impressively delivers 240 horsepower and 270 foot-pounds of torque.

This turbo four cylinder, which also is direct injected, makes the Taurus the most fuel-efficient, gasoline-powered, non-hybrid, 2013 full-size sedan in the United States.

The federal government fuel economy rating for this model is 22 miles per gallon in city driving and 32 mpg on the highway, with an estimated range of nearly 450 miles on a single tank of regular gasoline.

This mileage rating rivals the pricier, 2013 Mercedes-Benz E350 Bluetec, which uses diesel fuel and is a smaller-size sedan than the Taurus.

Also noteworthy: The 2013 Taurus earned across-the-board, five out of five stars for occupant protection in the government’s frontal and side crash tests.

Starting manufacturer’s suggested retail price, including destination charge, is $27,495 for a front-wheel drive, 2013 Taurus with the base engine, which is a 3.5-liter V-6 that generates 288 horsepower.

The lowest starting retail price of a Taurus with the EcoBoost four cylinder is $28,490.

And the lowest starting MSRP, including destination charge, for an all-wheel drive, 2013 Taurus is $31,545.

The EcoBoost four cylinder is not available with all-wheel drive.

All 2013 Tauruses come with six-speed automatic transmissions, though the transmission mated to the EcoBoost motor is different than the one used with the V-6.

And yes, there is a performance-oriented Taurus SHO model in 2013. It starts at $40,095. In contrast to SHO models from the past that had V-8s, the 2013 Taurus SHO comes only with a 365-horsepower, twin-turbocharged, EcoBoost V-6 and six-speed automatic.

Competitors to the Taurus include other mainstream full-size sedans, such as the front-wheel drive, 2013 Chevrolet Impala, whose starting MSRP, including destination charge, is $26,685.

The Impala comes with a 300-horsepower, 3.5-liter V-6 and automatic transmission and is rated by the government at 18/30 mpg.

Meantime, the 2013 Chrysler 300 large, rear-wheel drive sedan has a starting retail price of $30,990 with 292-horsepower V-6 and eight-speed automatic. Its government fuel economy rating is 19/31 mpg.

The 2013 Taurus is restyled on the outside, with new grille, lights, trunk lid, rear fenders and wheels updating the car with a fresh, more upscale appearance. But the new look doesn’t quite bring the Taurus to the same sporty styling “face” that the Ford Fusion, Focus and Fiesta have.

Inside, cheap-looking plastic from the predecessor Taurus is replaced by nicer-looking, textured plastic. And every Taurus comes standard with interior ceiling fabric that’s made from recycled material and seat foam that is made from a soy-based rubber.

Even Ford’s Sync system that can be used to control radio, ventilation, navigation and other settings is updated, in an effort to be more user-friendly. It still takes time, however, to learn the Sync system and commands, and a driver can get distracted working the touchscreen in the middle of the dashboard.

The EcoBoost engine really is the news. It costs only $995 more than the less fuel-efficient, base Taurus V-6 whose fuel economy rating is 19/29 mpg.

Plenty of passengers traveled in the test Taurus SEL with optional EcoBoost, and none guessed the powerplant was a four-cylinder gasoline engine.

The four-cylinder engine displacement is just 2 liters, but with dual overhead cams, direct injection and turbocharging, this EcoBoost four gets as much as it can from every gallon of gasoline.

Indeed, the test car, which traveled 70 percent of the time in city traffic, was driven spiritedly and frequently carried passengers, averaged more than 22 mpg.

Yet, the Taurus never lagged or seemed taxed. The car moved smoothly with traffic on city and highway roadways, and shift points from the six-speed automatic were not obtrusive.

Peak torque comes on by 3,000 rpm, which is a good for both decent acceleration and all-situation driving.

Note that the gas tank is a sizable 19 gallons, so fillups can be few and far between. In comparison, the lower fuel-mileage Impala’s gas tank carries 17.5 gallons, with the government estimating a full tank can go for 337 miles.

The Taurus also impressed with its quiet interior. Not much was heard from neighboring vehicles at stoplights, and conversations inside the car were in normal tones. There was a bit of road noise from the optional 19-inch, all-season tires, but wind noise was nicely muted.

The optional larger tires, by the way, included a fancy-looking finish that made the Taurus SEL, painted Deep Impact Blue, look upscale.

The 2013 Taurus has new, electric power-assisted steering and other fuel economy aides and it cruises comfortably on highways.

The car’s heft is noticeable, however, on back-and-forth curves on mountain roads.

The Taurus trunk is downright huge, with 20.1 cubic feet of space. A lot of this room extends way inside the trunk, under the rear parcel shelf. In comparison, the Impala’s trunk provides 18.6 cubic feet of space, and the 300′s trunk has 16.3 cubic feet of cargo room.

The black leather trim on the test Taurus seats looked good, though it wasn’t the most supple leather to the touch.

Front-seat legroom of 41.9 inches promises to accommodate just about any tall driver, while rear-seat legroom of 38.1 inches tops the Impala’s 37.6 inches and is less than the 40.1 inches that Chrysler says is in the 300 sedan.

Consumer Reports says predicted reliability for the Taurus is average.