January 4, 2011
Review and photos by Chris Chase
2011 Infiniti M
Four-wheel steering is nothing new, but only a handful of vehicles in recent memory have featured it, the most common, perhaps, being the Honda Prelude. There was also a short-lived four-wheel steering set-up offered on the GMC Sierra pickup truck. Nissan has experience with the technology too, and its Infiniti division’s M sedan is one of few vehicles on the market right now that uses it.
The Infiniti M (sold as the M37 and M56, named for their 330-hp 3.7-litre V6 and 420-horse 5.6-litre V8, respectively) is the company’s flagship, and as such, acts as a showcase for trick technology.
Checking the box for the M’s Sport Package gets you a number of extras, but the most notable is the 4-Wheel Active Steer system that activates when the M’s standard Infiniti Drive selector is set to “sport” mode. According to Infiniti Canada’s Robert Karwell, it differs from other four-wheel steering systems, including Nissan’s own previous Super HICAS (High Capacity Actively Controlled Suspension) in that it doesn’t have a proper rack-and-pinion set-up between the rear wheels; instead, it uses solenoids (glorified switches) that act on the suspension bushings to steer the rear wheels.
2011 Infiniti M37S. Click image to enlarge
It’s a lighter, less-expensive set-up that gives up Super HICAS’ ability to turn the rear wheels in the opposite direction (out of phase, or counter-steering) of the fronts to increase manoeuvrability in tight turns. Instead, the rear wheels steer in the same direction as the fronts (in phase) up to one degree when the car is at speeds above 40 km/h. Karwell says this new system tries to replicate Super HICAS’ counter-steering effect by decreasing the front steering ratio so that the front wheels turn more for every twist of the steering wheel than they normally would.
At speeds between 40 and 80 km/h, the rear wheels begin to turn in phase with the fronts to improve agility and stability; and above 80 km/h, the maximum amount of rear-wheel steer is realized (up to one degree), while the front steering ratio is dialled back to keep the car from feeling twitchy at highway speeds, according to Karwell. Ultimately, he added, 4-Wheel Active Steer’s goal is to improve the car’s stability in lane changes and high-speed emergency manoeuvres.
The four-wheel steering system is the technical highlight of the M’s Sport Package, but it’s not the only feature. The obvious additions are a set of 20-inch wheels and the red ‘S’ on the trunk lid; beyond that, you get better brakes (four-piston front and two-piston rear calipers), more aggressive front seat bolstering, sport-trimmed heated steering wheel with paddle shifters, adaptive (steerable) xenon headlights, navigation, intelligent cruise control, lane departure warning, lane departure prevention, distance control assist, intelligent brake assist with forward collision warning, blind spot intervention system, active tracing control, eco pedal, Forest Air system with air purifier, heated and cooled front seats, aluminum pedal accents and a power rear sunshade.
2011 Infiniti M37S. Click image to enlarge
The six-cylinder engine is strong, smooth and loves to rev all the way to its 7,500 rpm (!) redline, and while it doesn’t make the car fast, it does make it a swift, comfortable sedan. When the throttle pedal meets the floorboard, it sounds decent but the sound is almost too sterile and doesn’t inspire much enthusiasm; a more aggressive exhaust note would be a good fit with the Sport Package.
The M37S’ tighter suspension, low-profile tires and active steering sharpen the M’s reflexes, but at a tangible expense to ride comfort. Aside from activating the active steering set-up, Infiniti Drive also affects throttle response and transmission behaviour. Sport mode makes for right-now throttle tip-in and makes the transmission more eager to downshift and hold lower gears in aggressive driving. An “eco” mode dumbs everything down and engages Infiniti’s “eco pedal,” which uses force feedback to encourage lighter throttle applications in order to conserve fuel, and a Snow mode dials back throttle response even further to aid in managing traction in slippery conditions. Naturally, there’s a Normal mode too, with settings somewhere in between Eco and Sport.
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