It took 18 months, but General Motors has improved fuel economy on some already fuel-efficient small cars by fine-tuning technology.

The new technology, dubbed XFE for Xtra Fuel Economy, will be on the Chevrolet Cobalt LS and the 1LT models with manual transmissions. The technology also is used on the Pontiac G5. The technology gives Chevrolet a peg to tout fuel economy as consumers shop for fuel-efficient vehicles amid high gasoline prices.

"The timing to talk about it couldn't be better," says Cheryl Catton, Chevrolet's director of marketing for cars and small utility vehicles.

The Cobalt XFE model production started on March 17 after engineers spent a year and a half tweaking the Cobalt's engine to get better fuel economy, Catton says. GM engineers recalibrated the engine, but GM declined give details for competitive reasons.

It also added tires with lower rolling resistance.

"Those two factors and other technical changes resulted in better fuel economy," Catton says. The XFE Cobalt gets an EPA fuel-economy rating of 25 mpg in the city and 36 mpg on the highway. Its predecessor earned 24/33, Catton says.

Source: Automotive News