By Nat Shirley
Thursday, Dec 15th, 2011 @ 2:26 pm

The entry-level engine for the Cadillac ATS will not be the recently announced turbocharged 2.0-liter four-cylinder but rather a naturally aspirated 2.5-liter four banger.

The engine is likely the same unit employed by the 2013 Chevrolet Malibu. Under the hood of the ‘bu, the motor is expected to make about 190 horsepower.

The news comes as something of a surprise, as major ATS competitors like the BMW 3-Series, Mercedes-Benz C-Class and Audi A4 use force-fed four-cylinder mills as base engines. It would be well within Cadillac’s power to modify the 2.5-liter for extra horsepower to make it more competitive with the Germans on that front, although it will inevitably offer less torque.

Still, the engine could allow the ATS to undercut the starting prices of its rivals, and Cadillac is confident in the overall quality of its long-awaited sports sedan.

“This has been a segment dominated by German cars, and as such we’ve developed a compelling competitor,” said Dave Leone, GM’s global vehicle line executive for rear-wheel and performance cars.

The aforementioned 2.0-liter turbo four will be the mid-grade engine choice, while a 3.6-liter V6 will the be most powerful motor in non-V ATS models.