The 2011 Chevrolet Cruze hasn’t even gone on sale in the U.S. but already the first variants are being revealed. At this week’s 2010 New York Auto Show two new Cruze models will make their debut: the sporty RS and the fuel efficient Eco, the latter delivering a fuel economy as high as 40 mpg on the highway.

Both models come powered by a turbocharged 1.4-liter Ecotec four-cylinder engine with variable valve timing. Peak output from the engine stands at 138 horsepower and 148 pound-feet of torque and in most models should carry the car a distance of at least 500 miles on a single tank.

The new RS package is only available with the pricier LT and LTZ trim levels and is essentially a styling package for the Cruze compact sedan. The package includes unique bumpers, side skirts and a rear spoiler as well as a special instrument cluster with chrome accent rings.

The Eco package, on the other hand, is a special high efficiency model that’s expected to offer the best fuel economy in the compact segment. Full fuel economy figures will be finalized closer to launch but we can reveal that models equipped with a standard six-speed manual transmission should return numbers as high as 40 mpg on the highway.

Unique elements include a lower front grille air shutter that closes at higher speeds to improve aerodynamics and opens at lower speeds to optimize engine-cooling airflow, a lowered ride height, low rolling resistance ties and specially designed lightweight 17 inch aluminum wheels.

The axle ratio on the manual-transmission model is also optimized for fuel economy. Chevrolet estimates the Cruze Eco will deliver 0-60 mph performance of about 10 seconds with the manual transmission and 9 seconds with the six-speed automatic.

The 2011 Chevrolet Cruze and its various models will be available in the fourth quarter of 2010.