
Both 3.2-liter engines lag behind key rivals in both power and fuel economy. The 3.2-liter's 16/25 EPA rating is sub-par for this class, and the PZEV engine's 18/27 rating is no better than the bigger V6s in the Cadillac CTS or Lincoln MKZ, both of which have better overall performance and greater refinement.
The S80 T6 AWD has a 3.0-liter turbocharged six, rated at 281 horsepower and 295 lb-ft of torque. This engine, known as B6304T, has an intercooled twin-scroll turbocharger, designed to enhance power at low and mid-range engine speeds. The 3.0-liter turbo engine brings the S80's performance in line with similarly priced rivals, and its 16/24 EPA rating is only slightly worse than the 3.2-liter.
The top-of-the-line S80 V8 AWD has a 4.4-liter DOHC V8 with 311 horsepower and 325 lb-ft of torque. This all-aluminum engine, known as the B8444S, was designed by Volvo and Yamaha. It has an unusual 60-degree bank angle, making it compact enough for transverse applications. The 4.4-liter V8 is only slightly stronger than the 3.0-liter turbo, and its 311 horsepower is unimpressive for an engine of this size. The 3.6-liter V6 in the 2010 Cadillac CTS nearly matches the V8's power and soundly beats its thirsty 15/22 EPA rating.