The 2011 Infiniti M37 and Infiniti M56 are the all-new successors to the outgoing M35 and M45. Because the V6 and V8 engines are larger for 2011, the names have changed, but the changes go much farther than engines and model nomenclature. Just about everything on these cars has been redesigned for 2011. Lower and wider than the outgoing models, but not longer, the 2011 Infiniti M models are a great deal swoopier and far more eye-appealing than before.
The 2011 Infiniti M37 is the V6 version while the 2011 Infiniti M56 features the V8.
Both are available with all-wheel-drive, denoted by M37X and M56X. The M37X and M56X feature a part-time computer-controlled drive system to add engine power to the front tires when the driving situation calls for more traction. Sports suspensions are available for the rear-wheel-drive M37 and M56 models, and a hybrid version is scheduled to join the lineup.
The Infiniti M competes in the entry luxury sedan market segment with the Acura RL, Lexus GS, Audi A6, Mercedes-Benz E-Class, and BMW 5 Series.
Infiniti's V6 and V8 powertrains have received substantial upgrades for 2011, with far more torque and horsepower available from both engines. With a 330-horsepower V6 engine, the most powerful in its class, the M37 offers 27 additional horsepower, 18 more foot-pounds of torque, and far better acceleration performance than the outgoing M35. Similarly, the V8 engine, enlarged from 4.5 to 5.6 liters, fitted with direct fuel injection and variable valve timing and lift, produces 420 horsepower, or 95 horsepower more than the M45 of last year, and 417 foot-pounds of torque, or 81 more than the M45 engine.
Both engines now use a 7-speed automatic transmission with manual shift override, which yields better acceleration in the lower gears, and significantly better highway fuel mileage, up to four miles per gallon better, than the smaller, less powerful engines with the old 5-speed automatic transmission. The new transmission features four driving modes, including Normal, Sport, Economy and Snow, controlled by a knob on the center console. Sport models include magnesium paddle shifters with blip-throttle downshifting.
The width of the 2011 Infiniti M is increased by 1.5 inches over the previous version, to 72.6 inches wide. The overall height has been lowered by 0.3-inch (to 59.1 inches). However, the wheelbase is unchanged at 114.2 inches, and the length has grown by just 0.6-inch (to 194.7 inches). The front track increased by 1.5 inches on rear-wheel-drive models to 62.0 inches and the rear track has been increased 0.8 inches to 62.0 inches. (The track is the distance between the left and right wheels.) For AWD models, the front track has increased 0.9 inches to 62.0 inches and the rear track has increased 0.6 inches to 61.6 inches.
With all the changes, the new M is about the same weight as the old car because of lightweight material substitutions such as aluminum doors. The body shape and some underbody trickery yield a coefficient of drag for the new body of only 0.27 Cd, the world's lowest for a four-door luxury car.
Befitting and proper on any modern luxury sedan, the 2011 Infiniti M line bristles with electronic technology to make driving safer and more enjoyable. For instance, the M cars are available with a blind spot warning system that beeps to tell the driver there is a vehicle in the mirror's blind spot. The M also carries a lane departure warning system to warn the driver that he or she has crossed the centerline of the highway. If the driver doesn't respond to the warning, the blind spot intervention system steps in and applies the right front brake to gently guide the car back into the lane in which it belongs.
For audio enjoyment, there are three different sound systems on the M cars, including two Bose system upgrades. The Premium Package includes a two-channel, 10-speaker sound system by Bose, the Deluxe Touring Package adds a 5.1 surround sound system with a subwoofer and 16 speakers arrayed throughout the interior.
We found the Infiniti M56X has a lovely, sporty driving demeanor. The active noise-canceling system works very well, perhaps too well, because the cabin is so quiet that exterior factors like tire noise and wind noise around the mirrors can intrude. The cabin is gorgeous and roomy, although the rear seat headroom was reduced to obtain the new shape, and the controls arrayed around the 8-inch screen are very easy to use.