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Carmakers Find That Turbos Are a Powerful Path to Fuel Efficiency

Jamie Holland and her husband, Jarrod, of Wilmington, N.C., got rid of their older, nonturbocharged cars and replaced them with more fuel efficient turbo models: a BMW for her and a Ford for him.Credit...Mark Courtney for The New York Times

EVEN as electric cars stall with Americans, another fuel-saving technology is revolutionizing the morning commute: the turbocharger.

Once mostly the province of expensive sports and luxury cars, turbochargers are proliferating in everything from budget compacts to burly pickup trucks. As automakers scramble to lift their average fuel economy to 54.5 miles per gallon by 2025 — the target set by the Environmental Protection Agency — turbochargers have become a key to unlocking higher mileage without sacrificing the performance consumers demand.

In the process, analysts say, their efficiency has had the unintended effect of helping slow the broader adoption of alternative-fuel vehicles.

How does it work? A turbocharger essentially reuses hot exhaust gases — energy that would otherwise be wasted — to increase engine power in a smaller space. Hot exhaust spins a turbine wheel at up to 250,000 r.p.m., which compresses air and stuffs it into engine cylinders, allowing more fuel to be burned in a same-size engine.

That allows automakers to shrink engines, using six cylinders instead of eight, or four in place of six, while matching the power of the larger traditional engine. The downsized engines also beat their larger counterparts in low-end torque, a boon to effortless acceleration.

“It’s really a mini jet engine in your car,” said Michael Stoller, spokesman for Honeywell Transportation Systems, which supplies turbochargers to automakers around the globe.

The result is 10 to 30 percent better fuel economy, often in conjunction with direct fuel injection, which increases efficiency via precise, computer-managed sprays of atomized fuel.

With those advantages — bountiful power and savings at the pump — consumers and automakers are fully on board.

Jarrod Holland and his wife, Jamie, scaled down their engines.

Mr. Holland, a publicist in Wilmington, N.C., traded an 8-cylinder Dodge Challenger for a 2013 Ford Fusion sedan with its EcoBoost turbocharged 4-cylinder engine. His wife, a nurse, traded her 2011 BMW 3 Series for a 2014 BMW 328i sedan and its TwinPower turbo 4-cylinder engine.

The in-line 6-cylinder in Ms. Holland’s old BMW — long the signature power plant of the Bavarian automaker — is rated at 18 miles per gallon in the city and 28 on the highway. Her new BMW’s turbo engine, with 240 horsepower, is a third smaller, yet it has 10 more horsepower and a huge 60 additional pound-feet of torque, giving it faster acceleration. Yet with all this newfound power, she is getting about 32 miles per gallon on the highway.

“It drives so much better than the 6-cylinder,” she said. “I could never imagine a 4-cylinder engine could go that fast, but it just throws you back in your seat.”

By any industry standard, the pace of the turbocharger revolution has been breathtaking.

In 2011, less than 7 percent of new cars and trucks in America were sold with turbochargers. In just four years, that percentage has tripled to 21 percent. Honeywell forecasts that nearly four in 10 new cars and trucks in America will be turbo powered by 2019, or roughly eight million a year. By 2025, turbocharged engines are expected to be found in a staggering 80 percent of new cars.

Edmunds.com, the consumer auto website, says that 49.7 percent of the 350 car and truck models sold in America offer a turbocharged engine, up from 30 percent in 2010.

Make that 100 percent at Ford, which has been especially gung-ho: For 2015, every Ford and Lincoln car, sport utility vehicle and light-duty pickup offers an optional EcoBoost turbo. Seven EcoBoost choices range from a petite 1-liter, 3-cylinder in the Fiesta subcompact — smaller than many motorcycle engines — to the 2.3-liter, 310-horsepower version in the all-new Mustang, the first 4-cylinder in any Mustang since 1986. Atop the power heap is the V6 with 365 horses in the radically redesigned F-150 pickup.

Even traditional pickup buyers, notoriously skeptical of rapid technological change, have been won over: Half of Ford’s F-Series buyers, or well over 350,000 in a typical year, are choosing an EcoBoost-powered truck. The F-Series with a compact 2.7-liter EcoBoost V6 set a mileage record for full-size gasoline pickups at 26 highway m.p.g. Yet this roughly 4,500-pound truck still accelerates faster than some sport sedans, going from stoplight to 60 m.p.h. in about six seconds.

Seeing the writing on the wall, several manufacturers have dropped V6 engines entirely from their most popular family sedans, including the Hyundai Sonata, Chevrolet Malibu and Ford Fusion, in favor of turbocharged 4-cylinder engines.

Yet as with every car, including hybrids, mileage may vary. A heavy foot spools up the turbo for a boost of acceleration, but takes an unavoidable toll on economy.

Even Bob Fascetti, vice president of Ford’s global powertrains, succumbs to the temptation.

“They’re so fun to drive that I try to use all that torque,” Mr. Fascetti said. “But when you drive with just the power you need, you do get the efficiency. It’s nice to give the customer the option to drive any way they want.”

Mr. Stoller of Honeywell said that that dual nature was a key.

“If you’re traveling 60 m.p.h., where you only need 50 horsepower to maintain that speed, you’ve got a lighter and more efficient engine,” he said. “But you can still step on it and pass somebody.”

Like hybrids, experts say, turbocharged engines tend to be favored in mileage tests that involve few hard-throttle applications. Mr. Holland has been mildly disappointed with his Fusion’s real-world mileage.

“It advertised 26 m.p.g. over all on the sticker, and even with a light foot, I’m getting 22,” he said. “But that’s still a lot better than the Challenger, where I got 15 if I was lucky.”

Japanese automakers have been somewhat slower to get aboard, focusing more on hybrid technology.

Yet turbos are seguing into every imaginable vehicle, including $15,000 subcompacts, plug-in hybrids like the BMW i8 and $1 million supercars.

In Europe, which got a big head start in small engines, 67 percent of showroom cars are turbos, including virtually every diesel.

In the United States, Audi helped pioneer turbos decades ago and sprinkles them throughout its lineup. Keen for any one-upping edge with luxury buyers, Mercedes-Benz, BMW, Cadillac, Porsche, Ferrari and Aston Martin are revamping lineups with turbos of 400, 500, even 600 horsepower. Aston Martin — famed for silken, yet gas-guzzling V12 engines — recently sold Mercedes a 5 percent company stake in exchange for components including Benz’s downsized, biturbo V8 engines.

Mr. Stoller said that regulatory pressures and turbocharging’s ability to complement other fuel-saving technologies were driving the full-spectrum appeal.

Yet for Ms. Holland and her sizzling, yet sipping BMW, federal rules are beside the point.

“I’m a bit of a lead-foot,” she said, “so it’s the perfect car for me.”

A correction was made on 
Feb. 26, 2015

An earlier version of this article incorrectly included the Chevy Volt among plug-in hybrids with turbocharged engines. The Volt has a conventional engine.

How we handle corrections

A version of this article appears in print on  , Section B, Page 4 of the New York edition with the headline: Carmakers Find That Turbos Are a Powerful Path to Fuel Efficiency. Order Reprints | Today’s Paper | Subscribe

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