Following up on something we first heard in January, General Motors will unveil an all-new Chevrolet compact car at an auto show this fall, according to unnamed GM sources in an AutoWeek report. GM has tried—and failed—to develop a world-beating compact car several times over the past 25 years. Efforts included the original J-car platform, along with several Saturn iterations and even a joint-Toyota venture in Geo. But this time it could be different, due to the company's brand new 1.4-liter turbocharged four cylinder engine.

The motor will be capable of developing between 120 and 140 hp and could exceed 40 mpg, according to the report. "It's a pretty incredible engine; it's direct-injected with great power," the source said in the article. "The small-displacement turbos make it possible to get great power, so that GM might put it in the mid-sized products, too. It's an extremely important engine and a very capable powertrain."

The new car will not be called the Cobalt, according to the source; that car will soldier on through June 2010 as a 2009 model, though there's no word yet on whether or not production will continue after that.