Sales might be up for Detroit's three automakers, but prospects for some of their turbocharged cars might not be so great after Tuesday.

Consumer Reports magazine is reporting that turbocharged cars don't actually perform better than other types of cars - nor do they really get the driver more miles per gallon (mpg).

"While these engines may look better on paper with impressive EPA [Environemntal Protection Agency] numbers, in reality they are often slower and less fuel-efficient than larger four- and six-cylinder engines," said Jake Fisher, director of automotive testing for Consumer Reports, in an e-mailed statement to Bloomberg News.

"There are better ways to save fuel, including hybrids, diesels and other advanced technologies," the magazine added, according to the Los Angeles Times.

The New York-based publication found that turbocharged vehicles from Ford, Hyundai, and Kia were actually less fuel-efficient than the standard model Toyota Camry and Honda Accord. And while General Motors' Chevy Cruze clocked in slightly faster than a standard four-cylinder engine automobile, that minimal performance boost only amounted to an increase of 1.1 mpg.

GM spokesman Tom Read pinned the results as only semi-accurate, saying the car's efficiency depends on the driver's own tendency.

"However, if you have a heavy foot on a turbocharged engine, you're not necessarily going to see a lot of fuel economy benefits," he said. "[Mileage] is really dependent on how you drive."

Wes Sherwood of Ford, meanwhile, simply stated that Consumer Reports' study doesn't match up with the company's own internal research.

Companies like GM and Ford have moved to turbocharged cars hoping to build smaller engines that maintain the power of larger ones. The idea is that by pushing more air through the engine, they could increase power even as they sacrifice size. Consumer Reports, however, said that all that air needs to be enhanced with extra fuel, canceling out any energy-saving benefits implied by a smaller engine.

Japanese car manufacturers like Toyota and Honda have avoided creating turbocharged vehicles up until now, but it doesn't look like these new findings are going to stop anyone else from creating their own line-ups

"We're going 100 percent into turbo technology," said Rainer Michel, vice president of product strategy for Volkswagen of America, to the LA Times. "From a physics standpoint, nobody will get around it."