2012 Infiniti M56x Review

2012 Infiniti M56x - Infiniti's largest sedan packs under hood excitement.


Infiniti, Nissan's luxury division on the road since 1989, zeros in on drivers seeking a bit more thrills to complement their posh surroundings.

While Infiniti's mid-size G line (available in sedan, coupe and convertible variants) rates as the volume leader, the larger M class is for those demanding more under hood excitement. Unlike Infiniti's multi-dimensioned G, the flagship M is comfortable with a sedan-exclusive bodystyle.

The M underwent a complete next-generation makeover in the 2011 model year, and late last year, began offering   a gas-electric hybrid system, the first hybrid ever from an Infiniti family member. Size wise, M fits comfortably in the gray area between a large mid-size or small-full size. Minimal updates in 2012 include an 18-inch larger wheel package ($650) and a combining together of select option packages. Infiniti supplied dark hued 2012 M56X for testing.

Deconstructing the alpha-numeric naming code, 56 represents the 5.6-liter V-8 powertrain while x denotes all-wheel drive, handy when the streets of Chicagoland turn ugly. This 5.6-liter engine (bellowing out a class-distinctive 420 horsepower) utilizes direct gas injection while teamed to an advanced seven-speed automatic transmission.    With direct gas injection, highly pressurized fuel gets direct cylinder injection during the compression stroke improving fuel economy and power output. The M line also offers a six-cylinder variant, the M37 with a 330 horsepower, 3.7-liter V-6 power source also mated to the seven-speed auto trans. Both engines are available with rear-drive or all-wheel drive; aka the x factor.

Infiniti's largest luxury sedan remains ideal for those seeking a firmer, sportier ride over a softer, plushier experience. The M also boasts more under-hood muscle than other worthy upmarket Asian counterparts such Lexus' 2012 LS 460 and 2012 Acura RL. The sole powertrain in the $47,700 RL is a capable but pedestrian 300 horsepower V-6. Lexus' largest sedan, the $67,630 LS includes a 380 horsepower V-8 standard but lacks the low-end torque and attitude the M56 proudly presents.

From Northern Europe, BMW's long-standing 7 Series ($71,000 starting price), has served as a benchmark, but with a substantial price premium.  South Korean automaker Hyundai turned heads when introducing the full-size, full-luxury Equus sedan into the fray, but the well-appointed Equus lacks all-wheel drive and M56's low-end power thrills.

Our all-wheel-drive M56 registered 16 miles per gallon city and 23 highway, besting BMW-s all-wheel-drive, 400-horsepower 750i (14 mpg city, 20 mpg highway). When opting for rear-drive, numbers, improve to 18 mpg city and 26 mpg highway. Premium grade unleaded fuel is required for the 20-gallon tank.

The lowest-priced M, a rear drive six-cylinder starts at $47,700. A rear-drive M56 checks in at $59,200. Our M56x tester listed at $61,600.  Options included a $3,800 deluxe touring package with power rear sunshade, white ash wood trim, silver-powder interior accents, 16-speaker Bose premium audio system and upgraded leather seating. Also optional were 18-inch aluminum alloy wheels (with all-season tires) brining the bottom line to $66,925 including an $875 destination charge.

The M56 comes standard with heated steering wheel, heated/ ventilated front buckets and in-dash navigation.  These items remain optional as a 'premium package' in the V-6  M37. An optional tech package (only available when ordering the deluxe touring package, but not part of our tester) includes a lane departure warning system, radar-enhanced cruise control, blind spot warning and blind spot intervention.

The flat instrument panel features two circular analog gauges flanked along the outside corners by two smaller, three-quarter varieties. In the center is a digital message window. The remote electronic button releasing the trunk lid is under dash on the driver's left side near the heated steering wheel button. The standard circular push-button electric start button resides on the upper dash left of the steering wheel, a better location than a recently tested Infiniti G37's, in which the steering wheel blocked access to the button at times.

Cozy power leather front bucket seats envelope the torso while the front dash includes soft-touch materials and white ash wood trim. After a three-hour trek to central Wisconsin, back fatigue was nonexistent.  From a center turn knob between the front buckets, drivers choose from four drive mode/shift point selections:  snow, eco, sport and normal.  During highway/tollway driving north, Eco mode got the call to maximize mileage.  Adjacent are two smaller twist knobs controlling ventilation and heating functions for the buckets. An elegant touch is a rectangular bejeweled analog clock smack dab in the middle of the center dash.

The stepped center region includes the monitor/navigation screen atop with the face clock flanked by air vents the next step down. The level below  includes a shelf of push  buttons  monitoring ventilation functions.  The face of this same step sports audio functions, including two welcomed knobs controlling volume and station selection.   A row of pre-set buttons are between.  All-in-all, the interface is very driver friendly. The upgraded stereo includes speakers atop of the front bucket seats flanking headrests. Three months of complimentary XM Satellite Radio for listening pleasure and sampling, after which a small monthly subscription takes hold.  The optional ecru-tinted suede headliner also adorns A and B pillars, contrasting nicely with the black leather and soft-touch dashboard.

The power tilt and telescoping four-spoke, heated steering wheel includes secondary audio functions on the left and cruise controls right. When calling upon reverse, the eight-inch in-dash monitor screen displays the backup camera feed. Also, the driver's and passenger side heated side view mirrors tilt downward to tackle and minimize side blind spots when backing. The driver's door is home to power windows, mirror and lock functions. Headroom in front and back comfortably accommodates those six-feet three or shorter.

Second row guests must share the floor with the rear-drive vertical floor hump, and comfortable seating for two adults. The back rest's center region includes a fold-down dual-cup holder arm rest with pass-through window to the cavernous trunk. The 14.9 cubic foot trunk includes strut-like dampers outside the cargo area, eliminating any potential encounters with cargo.

Drivers look out towards the hood and arched front fenders.  Narrow high-intensity discharge Xenon headlights housing flank a vertical-slated chrome front grille with oval Infiniti logo front and center. Strap-like, chrome plated handles adorn all four side doors while chrome trim surrounds side windows.  After dark, grab handles illuminate as long as the key fob is in the vicinity. The V-8 engine in M56x and M56 sports dual exhausts.

At a glance:

2012 Infiniti M56x sedan

Price as tested:  $66,925

Engine:  5.6 -liter V-8 engine

Horsepower:  420

Fuel estimates:  16 mpg city, 23 mpg highway

Length:   194.7 inches

Wheelbase:   114.2 inches

Height: 59.6 inches

Curb weight:   4,224 pounds

Assembly:   Tochigi, Japan

Dave Boe

Dave Boe, a lifetime Chicago area resident, worked at the Daily Herald, Illinois' third-largest daily newspaper, for 24 years. In 1989, the Daily Herald began a weekly Saturday Auto Section and he was shortly appointed editor. The product quickly grew into one of the largest weekend sections in the paper thanks to his locally-written auto reviews, the introduction of a local automotive question-and-answer column, a new colorful format and news happenings from Chicago area new-car dealerships.

Five years later, a second weekly auto section debuted on Mondays with Boe adding an industry insight column and introducing a "Love Affair with Your Car" column where readers sent in their own automotive memories for publication. During the next 10 years, the number of weekly auto sections Boe edited and coordinated grew to five and featured expanded NASCAR racing coverage, a dealer spotlight/profile feature and a Car Club Calendar where grass-roots automobile clubs could publish upcoming events for free. Boe also introduced more local automotive columnists into the pages of the sections, all of whom were seasoned members of the well respected Midwest Automotive Media Association. In 1997, Boe earned the Employee of the Year award from the Daily Herald.

Boe is a founding member and current president of the Midwest Automotive Media Association. He has degrees in Journalism and Business Administration from Northern Illinois University.