10 Top Cars with Improved Mileage

DETROIT ( MainStreet) -- Two ways for automakers to get to higher fuel efficiency ratings: develop new vehicles or redesign old ones.

New vehicles such as the Chevrolet Cruze have done well for the Detroit Three, and new models such as the Volt point the way to the future, but redesigns to existing vehicles can be quicker and less costly.

"It's far more cost-effective to work with what you have and to provide consumers with options that are more to their liking," says Ivan Drury, an analyst for Edmunds.com, which has compiled a list of the 10 vehicles with the biggest mileage gains since 2008.

In general, vehicles made it to the list because at some point between 2008 and 2012 they began to offer options such as six cylinders instead of eight, or four cylinders instead of six, or diesel engines. The move to four-cylinder engines has probably been the most important step as the overall U.S. fleet has become more fuel efficient.

One result of the change is that U.S. automakers are better prepared for high fuel prices. In February, the industry enjoyed dramatic sales growth despite a rapid increase in fuel prices.

On the GM ( GM) sales conference call last week, executive Don Johnson was asked whether the automaker would be in as good shape if it had the same model lineup today as it did in 2008, a year industry sales began a two-year decline that took them from 16.1 million in 2007 to 10.3 million in 2009.

"We wouldn't be," Johnson responded. "We're in a very good position now because of our car portfolio complementing our strong trucks."

Among the top 10 cars in terms of improved fuel efficiency by percentage since 2008, GM has two, the Buick LaCrosse and the Chevrolet Equinox.

Here is the list, compiled by Edmunds.com:

10th-best: Volkswagen Passat

Passat ranked 10th-best in terms of improved fuel efficiency by percentage between 2008 and 2012, with a 23.7% gain to 27 miles per gallon from 21.8 miles per gallon.

February Passat sales totaled 8,189. For the month, Volkswagen sales rose 43%, to 30,577, the automaker's best February since 1973.

The 2012 Passat, a midsized sedan, was unveiled in 2011 and is being built at the Volkswagen plant in Chattanooga, Tenn., which opened in April.

The big reason for the improvement, Drury says, is that the 2012 model year included a diesel version that had been unavailable since 2005. About a third of 2012 model sales are for the diesel version.

Diesel long had a bad name among U.S. consumers. In a recent story about the 10 worst cars ever made, Edmunds.com staffers chose the 1979 Oldsmobile Cutlass as No. 10 -- a result of GM introducing a diesel-engine car when it had not mastered the technology.

"GM was trying to market a technology that wasn't ready for prime time," Edmunds.com editor Scott Oldham says. "The cars never really ran property. They were underpowered. They blew up. They broke. They didn't run. It was a warranty disaster."

The failure of the Cutlass diesel "turned Americans off to diesel," Oldham says. "It is one of the reasons why diesel is still a bad word in this country."

The perception is slowly changing. "Everything is different now from the perception that diesel means slow and noisy. Nowadays, you can't tell," he says. "You would have to know from the scent of the fuel."

The miles per gallon for the diesel version of the Passat is in the mid-30s, he says.

Ninth-best: Buick LaCrosse

LaCrosse, another midsized sedan, ranked ninth-best in terms of improved fuel efficiency, with a 24.1% gain to 26 mpg from 20.9 mpg.

LaCrosse sales rose 21%, to 5,228, in February, making it the best-selling Buick, while Buick sales lost 11.3%.

While the 2008 LaCrosse came with six cylinders, the redesigned 2012 models include a four-cylinder model and a hybrid as well as an improved transmission, Drury says.

Eighth-best: Porsche Cayenne

Cayenne ranked eighth-best in terms of improved fuel efficiency, with a 24.8% gain to 18.3 mpg from 14.7 mpg.

Cayenne is a five-seat midsize luxury crossover. Porsche sold 657 units in February.

Drury says the fuel mileage improved because in 2008 "buyers were gravitating toward performance variants," but now "a new hybrid makes up 10% of sales." The 2011 Porsche Cayenne S Hybrid was introduced in the U.S. in November 2010.

Seventh-best: Hyundai Sonata

Sonata, another midsized sedan, ranked seventh in terms of improved fuel efficiency, with a 25.8% gain to 27.7 mpg from 22 mpg.

In February, Sonata sales rose 11%, to 17,425 units.

Drury says a 2010 redesign eliminated the six-cylinder version of the car and that now all versions have four cylinders.

Sixth-best: Ford Explorer

Ford's (F) Explorer ranked sixth in terms of improved fuel efficiency, with a 27% gain to 19.5 mpg from 15.4 mpg.

In February, Explorer sales rose 8%, to 10,440 units.

Drury says Ford "went over it every possible way" for a 2011 redesign that, among other changes, eliminated an eight-cylinder engine and abandoned a boxy SUV look in favor of a more aerodynamic crossover look.

Options include engines with four cylinders and turbocharged, direct-injection EcoBoost engines.

Fifth-best: Mercedes-Benz SLK Class

The SLK Class Mercedes, a convertible with a retractable hardtop, ranked fifth in terms of improved fuel efficiency, with a 28.3% gain to 23 mpg from 17.9 mpg.

In February, SLK Class sales totaled 286 units.

Drury says a 2012 redesign moved the car to a single option of a six-cylinder engine with direct injection.

Fourth-best: Dodge Challenger

The Dodge Challenger ranked fourth in improved fuel efficiency with a 30.3% gain to 19.5 mpg from 15 mpg.

In February, Challenger sales rose 14%, to 3,369.

"This one is playing well for Dodge," Drury says. "It looks good because in 2008 you could only purchase an eight cylinder -- the highest-performance version with the worst fuel economy."

Dodge followed limited-edition production in 2008 with a 2009 version that "included whatever you want, six cylinders as well as eight," Drury says.

Third-best: Kia Sorento

The Kia Sorento midsized crossover ranked third in improved fuel efficiency, with a 30.4% gain to 22 mpg from 17 mpg.

In February, Sorento sales fell 2%, to 8,386.

Drury says the mileage improved largely because a four-cylinder engine option was restored after being eliminated for the 2007 through 2010 models. Also, the newest model has unibody construction, rather than a truck frame.

Second-best: Chevrolet Equinox

The Chevrolet Equinox midsized crossover ranked second in improved fuel efficiency, with a 32% gain to 25.1 mpg from 19 mpg.

In February, Equinox sales rose 16%, to 17,851.

In a 2010 remodel, a four-cylinder engine became available, Drury says.

The best: Audi A3

The Audi A3 ranked first in improved fuel efficiency, with a 38.5% gain to 29.1 mpg from 21 mpg.

February sales of the A3 rose 15%, to 469.

Drury says a 2009 changeover replaced a six-cylinder engine with a four-cylinder version and made a diesel engine option available. In February, he says, 54% of A3 sales were diesel-powered.

-- Written by Ted Reed in Charlotte, N.C.

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