Big luxury SUV sets benchmark for performance.

Introduction

The Infiniti QX56 delivers class-leading capabilities among the full-size luxury SUVs. The QX56 comes with one of the most powerful V8s in the class. It boasts the top tow rating. And it offers serious off-road capability, an area where Nissan has a lot of experience. The QX56 is based on the full-size Nissan Titan pickup and Armada SUV. 

The Infiniti QX56 is the perfect choice for pulling a boat or a horse trailer while hauling seven passengers in luxurious comfort. It offers seating for seven or eight and is rated to tow 8,900-9,000 pounds. Nissan's 5.6-liter 32-valve engine generates more torque than the V8s in the Cadillac Escalade and Lincoln Navigator. The Lexus LX470 and Toyota Sequoia can't compete with the Infiniti's towing capability. 

Out on the highway, the QX56 is smooth and quiet, benefiting from a four-wheel independent suspension and a smooth five-speed automatic. It feels responsive and sure-footed on winding roads. Yet it's capable off road; its four-wheel drive-system features a low range, and skid plates are available. It comes standard with latest in electronic stability control, traction control and ABS technology, all of which can help you maintain control in emergency handling situations, and the available all-wheel-drive system further improves handling stability in slippery conditions. 

The QX56 is as luxurious as the best of them. Its opulent cabin is lathered in leather and stuffed with technology. It comes standard with a navigation system, an optional feature on many vehicles. Introduced as an all-new model last year, the Infiniti QX56 gets more standard equipment for 2005, including its RearView camera, which projects a picture of what's behind the vehicle onto the navigation system monitor. 

Lineup

Infiniti QX56 comes as one fully loaded model. It's telling to note there are only a few factory options. You need only choose between two-wheel drive ($47,750) and four-wheel drive ($50,750). The 5.6-liter V8 is rated at a 315 horsepower and 390 pound-feet of torque, and the transmission is a five-speed automatic. The four-wheel-drive system includes a low range. 

Leather-trimmed upholstery and the navigation system are standard. Also standard: Xenon HID headlights, a power liftgate, and a park-assist system. Standard wheels are 18-inch chromium aluminum alloy, with 20-inch wheels optional. The QX56 comes with a full-size spare tire. 

Options include a middle split bench seat in place of the standard two captain's chairs (no charge), a DVD-based entertainment system ($1,600), a power sunroof ($1,200), adaptive cruise control ($800), Sirius or XM satellite radio ($400), and painted fender splash guards ($200). Skid plates protecting the transfer case, oil pan and fuel tank on the four-wheel-drive edition are an available option for serious off-road travel. 

Safety features include the latest generation front airbags that deploy at different rates depending on crash severity and occupant seatbelt use and front-seat side airbags. Full-cabin curtain airbags come standard for improved head protection for passengers in all three rows in the event of a side impact or rollover. A rearview video system comes standard for 2005. When the transmission is in reverse, this system displays on the navigation screen the view from a camera mounted above the rear license plate. 2005 QX56 models have been upgraded to include active head restraints for the front passenger position. 

Walkaround

The QX56 may be the best tool this side of an 18-wheeler for clearing slower traffic out of the left lane. Spying one in a rearview mirror closing rapidly will inspire most drivers to err on the side of survival and get out of the way. It's not any one aspect but the combination. 

Perhaps it's the waterfall grille visually surrounded by large expanses of metal. Or the high headlights. Or the huge black intake vent embedded in the bumper above the grille. Whatever, as assembled the QX56's front end embodies massiveness. 

The side view broadcasts a similar message. Here, for once, and for this message, the more tire the better. On most vehicles, the popular practice among stylists is to wrap ever thinner tires around ever bigger wheels, with an eye to communicating sportiness. However, in this class, where mass and perceived hauling capability is the measure, tires that look like they belong on a truck are preferred. And the QX56 delivers (with 70-series tires on 18-inch wheels). 

Squared off, clearly defined, barrel-like fender blisters add heft to the quarter panels. The arched roof over the passenger compartment pushes the D-pillar rearward, shrinking and reshaping the rear quarter windows in conflict with the somewhat organic outline of the front and rear door windows. Nissan's signature rear door handle is placed awkwardly on the C-pillar. The running boards seem more cosmetic than functional, but manage to pull bodywork down below the midline of the wheels, again adding to the impression of mass. 

From the rear, the QX56 succeeds in presenting a strong stance. Substantial tires, widely spaced beneath a body that starts out broad at the lower reaches and then gradually tapers in towards the top suggests solidity and road-hugging stability. The QX56 comes with LED tail lights and brake lights that light up quicker and brighter than traditional bulbs. 

Interior

The Infiniti QX56 is big and roomy. In almost every measure by the tape, the QX bests the Cadillac Escalade and Lincoln Navigator, its most direct competition. The Infiniti beats these competitors by more than three inches in second-row legroom, and in most measurements it beats them by at least an inch. Only the Cadillac consistently betters the Infiniti in occupant space, and then generally by fractions of inch. Expansive window glass adds to the feeling of spaciousness in the QX56. 

All seats are trimmed in leather. The shift knob is similarly gloved and the steering wheel is wrapped in leather accented with wood inserts. The front seats are almost plush, nicely bolstered with adjustable inboard armrests, and heated. Second-row bucket seats are less plush, but still adequately bolstered with adjustable inboard armrests, and heated. 

Grab handles on the inside of the A-pillars and above the rear side doors offer assistance to shorter and less agile passengers getting in and out. Second-row seats tilt forward with little effort for access to the third row, which is more bench-like with barely adequate bottom cushions. Step-in height is comfortable, imparting a feeling of climbing up into the Infiniti. 

The dashboard is uncluttered, with broad expanses of pleasantly textured surfaces. There's no seam for the passenger SRS airbag, no Infiniti logo or label. The hood over the instrument cluster is topped with a satin finish, minimizing glare. In other words, nothing looks cheap; in fact, quite the contrary. Buttons and knobs return the expected quality tactile feel. 

The center stack, holding the stereo, climate and navigation system control heads, is inset in a metallic-looking frame housing large, adjustable airflow vents. Unfortunately, these center vents cannot be closed, always allowing some air to flow any time the climate control system is running; same for the vents at the ends of the dash. Inset in the top is the navigation system display, which also reports vital data about audio and climate control settings; watch for dust and other detritus to collect in the front of the opening. Unfortunately, the clock, an Infiniti-signature analog unit and a classic visual, is tucked away down at the bottom of the center stack, almost out of sight and therefore almost out of mind. 

Instruments are of the floating luminescence type, which militates for leaving headlights in automatic mode as the always-lighted gauges can lead even an attentive driver into thinking the exterior lights are on when they are not. The ignition key slot is in the dash, where it by right ought to be. Real-looking, light-colored wood covers the center console. 

The front windows have one-touch, auto-up/down power; a plus is that the rear door windows do, too. Another plus are power rear quarter windows. The brake and accelerator pedals are power-adjustable, especially useful to allow smaller drivers to place themselves farther from the steering wheel where the airbag is housed; the placement of the adjustable pedals is included in the memories for driver's seat and heated outside mirrors settings. Each front seat occupant may choose an individual temperature setting, and rear seat passengers have their own thermostat as well. The 265-watt stereo includes a subwoofer among its 10 speakers. 

There's plentiful storage, with fixed map pockets in the front and rear doors. The back of the driver's seat boasts a hinged magazine holder. Eight cup holders are provided. A modest amount of hidden storage space resides beneath the cargo floor behind the rear seat. Ordering the entertainment system parks a DVD player in the front center console, slashing that space by about one-third. 

Collapsing the rear and middle seats and folding the front passenger seat back down makes enough room for an eight-foot ladder. If the rear captain's chairs have been installed, however, a console between them obstructs loading any objects that are bot. 

Driving Impression

From the driver's seat, the Infiniti QX56 doesn't feel as large as it is. Without a regular check in the rearview mirror, you might forget just how much mass is back there. That's not to say it drives like a car, but nor does it drive like the full-size body-on-frame truck that it is. 

It handles quite well for such a big vehicle. There's a modicum of body lean in corners. The steering feels precise, with good variable assist. The combination of comfortable ride and responsive handling comes from the four-wheel independent double-wishbone suspension with front and rear stabilizer bars. The independent rear suspension improves ride and handling on rough roads. It especially helps smooth the ride for those seated in the second and third rows. 

An advanced rear auto-leveling air suspension (which comes standard) improves stability and ride comfort when towing or hauling cargo. The air suspension maintains a uniform ground clearance and departure angle by automatically adjusting the air pressure in the system's air bladders. The QX56 is rated to tow up to 9,000 pounds with 2WD or 8,900 pounds with all-wheel drive, more than the Navigator (8,600) or Escalade (8,100). A Toyota Sequoia is rated to tow 6,500 pounds. 

Nissan's 5.6-liter, 32-valve, double overhead-cam V8 offers impressive output, rated in the QX56 at 315 horsepower at 4900 rpm and 390 pound-feet of torque at 3600 rpm. That easily trumps the Toyota Sequoia's 282 horsepower and 325 pound-feet of torque. The Lincoln Navigator, impressively revised for 2005, offers 300 horsepower and 365 pound-feet of torque. The Cadillac Escalade comes with a 6.0-liter overhead-valve V8 that boasts 345 horsepower at 5200 rpm and 380 pound-feet of torque at 4000 rpm, but note the higher rpm. Towing demands high torque at low rpm and that's where the Infiniti's power is concentrated. 

Acceleration performance is less than sparkling, however. The most likely reason for this is weight: An Infiniti QX56 AWD tips the scales at 5,631 pounds. That's slightly heavier than the Cadillac but a little lighter than the Lincoln. Nissan's overhead-cam engine sounds good, though, producing the appropriate big-V8 exhaust tones when you mash the gas. 

Braking is solid and linear, with good, manageable pedal feel. The QX56 features four-wheel disc brakes with ABS. The antilock brake system is barely felt when called upon and allows the driver to maintain steering control under hard braking. Electronic brake-force distribution (EBD) improves stability under braking, while Brake Assist helps the driver get maximum braking performance in an emergency stopping situation. The electronic stability control system intervenes when the QX is pushed beyond the limits of grip, driving too quickly into a slushy corner, for example, and corrects the imbalance with little excitement. 

Perhaps Q stands for quiet. Very little tire and road noise invades the cabin, thanks mostly to abundant sound-deadening material. Some wind noise is unavoidable, given the roof rack complete with cross rails, but it's reasonably muted. 

The QX56 is available with rear-wheel drive or an all-wheel-drive system. The AWD system offers 2WD, 4HI and 4LO modes. A two-speed electronic transfer case allows the driver to select low ranges for 1st, 2nd and Reverse gears for seriously rugged terrain. The AWD system is designed to instantly distribute torque to all four wheels whenever road conditions warrant. Under normal driving conditions, AWD QX56s operate in rear-wheel drive mode for optimum fuel economy. But when conditions warrant, up to 50 percent of the power is transferred to the front wheels on demand, resulting in optimum traction. All AWD QX56s include heavy-duty skid plates for the oil pan, fuel tank and transfer case. 

Summary

The Infiniti QX56 raises the bar in dimensions and styling, outside and inside, and in power and drivetrain. It offers exceptionally good off-road capability in its class. It's surprisingly responsive and surefooted on freeways and backroads. 

New Car Test Drive correspondent Tom Lankard is based in Northern California. 

Model Lineup

Infiniti QX56 2WD ($47,750); AWD ($50,750). 

Assembled In

Canton, Mississippi. 

Options As Tested

DVD entertainment system ($1,600); two-way power sunroof ($1,200); intelligent cruise control ($800).