While the 2009 Buick Lucerne Super offers exciting acceleration and power, the new 3.9-liter V-6 in the CX and CXL is no improvement over last year's 3.9-liter engine.
The new V-6 engine delivers 227 horsepower—a 30 hp improvement over the last year’s 3.8-liter V-6. Powering the Super is a 4.6L Northstar V-8 engine with 292 horsepower and 288 lb-ft of torque. Paired to either engine is an electronically controlled four-speed automatic transmission.
“Despite its additional 30 horsepower, the new V6 doesn't feel much more responsive than the previous one, still providing only adequate around-town power. The Super's V8 is noticeably stronger, particularly in highway merging and passing power, but neither matches the rival Chrysler 300's V-6 and V-8 engines for outright muscle,” says ConsumerGuide. All Lucernes shift through a four-speed automatic. ConsumerGuide calls it “smooth-shifting,” but Edmunds notes that while the 2009 Buick Lucerne 's transmission "shifts smoothly enough," its "tall, widely spaced gear ratios hurt both performance and mileage"—which is "not a good thing in a class where competitors' transmissions offer five or even six forward gears."
Kelley Blue Book says, “The standard car allows relatively spirited driving (more aggressive than its buyers will likely attempt) with adequate power, good control and solid braking.” The EPA rates the Lucerne at 16 mpg city, 25 highway for the V-6 version, while the Super at the top of the line gets 15 mpg city, 22 highway. Edmunds also notes "real-world fuel economy often falls well below the 20-mpg mark." This is true of in-town driving, although the Buick Lucerne does better on the open road.
Edmunds reports that "handling is mediocre on the softly tuned Lucerne CX and CXL models, which exhibit considerable body roll during cornering," but acknowledges that the Super is somewhat firmer and more controlled, due largely to its magnetic shocks and 18-inch wheels." Autoblog says "an enhanced chassis with a specially tuned version of Lucerne's Magnetic Ride Control system, for a refined, premium ride that simultaneously enables crisp, responsive handling."