Under the hood
According to Infiniti's marketing materials, the FX50S is a "Luxury SUV with the Heart of a Sports Car." With a 5-liter V-8 cranking out 390 horsepower, we're inclined to believe them. Stomp the go pedal from a stop and a wave of torque--369 foot-pounds to be exact--hustles the 4,575 pound vehicle forward at a fantastic rate. The sound from Infiniti's trademark tuned exhaust evokes the exotic sound of the G35 and G37 sports coupes, but is deeper and more guttural to fit the larger engine and body.
You won't fool yourself into thinking that you've accidentally sat down in an M3--the FX50S' speed is only impressive relative to its size--but as far as we can tell, the FX50S' performance is only eclipsed by one other SUV, the Porsche Cayenne GTS.
While the engine supplies the power, the transmission controls the flow of power to the wheels. Left in Drive, the seven-speed automatic transmission shifts smoothly and low in the powerband, as it attempts to balance fuel economy and power delivery. Floor the gas while in this mode and you'll be greeted with a second's delay while the vehicle decides whether you actually want to go fast or you just sneezed. It's quite annoying when trying to merge into tight traffic. However, nudge the shifter over into the Sport mode and the FX50S takes on a different character. Throttle response sharpens, shifting occurs at much higher revs, and the transmission is more eager to drop down a gear when provoked.
Steering-column-mounted paddle shifters allow even more flexibility, giving the driver complete control over when shifts occur. This is both a gift and a curse, as the FX50S' redline is vaguely defined and very unforgiving. An aggressive fuel-cut occurs about 6,000rpm, despite redline being marked at about 6,800rpm. Miss a shift and you'll be punished with massive amounts of engine braking that hits like a ton of bricks, throwing the vehicle off balance. After a few scares, we decided to just let the computer do the shifting.
While we agree that the FX50S' engine may be the heart of a sports car, it still has the legs of a truck. The front double-wishbone and rear independent-multilink suspension performs admirably, with the assistance of the gratuitous amounts of rubber wrapping the 21-inch wheels, but the FX50S can't disguise its weight when turning. Our model included the optional Sport Package, featuring the Continuous Damping Control that adds a Sport mode to the suspension. In Sport mode, body roll is reduced at the expense of some smoothness over bumps. Left in Auto mode, the suspension firms or softens the suspension depending on vehicle demands, keeping the vehicle flat in the turns and comfortable on freeway blasts. The suspension seemed to adjust so quickly that we didn't notice a difference between Sport and Auto modes during spirited driving.
Our sole complaint about the FX50S' handling is with the vehicle speed-sensitive power steering. While we liked that the steering was light at lower speeds and weighty at highway speeds, when the vehicle is stopped, the power steering cuts out completely, requiring great strength and strain to move the wheel. This makes parallel parking in tight spots nearly impossible, because you can't turn the wheel when the FX50S is stopped to tuck the nose into the spot. We're particularly frustrated by this flaw, because it all but defeats the purpose of the Around View Camera, which should make the FX50S an all-star at getting into tight spots.
You'll pay the price for breaking the laws of physics at the pump. The FX50S' EPA estimated 14 city and 20 highway miles per gallon isn't bad for a vehicle of this size and output, but it'll certainly never be called "thrifty." If you're a lead-footed driver who enjoys feeling the kick of a 5-liter V-8, like CNET's Car Tech Editors, you can expect your practical combined fuel economy to hover about the 15-16 mpg range.
We absolutely loved the Around View Camera and spent hours inching the FX50S around parking lots, watching the road go by on the screen. This is probably the first safety feature that we could describe as fun to use. The rest of the cabin is also fantastic, with comfortable leather seats, an impressive amount of well-designed entertainment options, and an operating system that allowed the driver access to three flexible control schemes: speech, touch screen, and the control knob.
While we expected big power from a vehicle that advertises its 5 liters of displacement in its model number, we were genuinely impressed by the acceleration and willingness to change direction that the FX50S exhibited. We didn't like unnerving way the engine management handled the rev-limiter or the way the power steering behaved at the lowest of speeds, but overall the FX50S performed admirably.
Our 2009 FX50 starts out at $56,700, which includes the Around View Camera, hard-drive navigation with 9.3GB of MusicBox space, and the Bose Audio system with Bluetooth as standard features. Adding the Sport Package for $3,000 adds the Continuous Damping Control suspension that puts the "S" in FX50S, sport style front seats with adjustable bolsters, and auto-leveling and steering Xenon HID headlamps. Next, adding the $2,000 Technology Package brings more safety tech to the party, including lane departure warning and intelligent cruise control. Those anticipating filling the rear seat up with passengers will want to consider the $1,600 flip-down DVD player. Add an $815 destination charge and you end up with an as-tested price of $65,015.
The robo-hippo looks and performance of the Infiniti FX50S are outgunned by the more refined Porsche Cayenne GTS on the Concours and on the track, but only just barely. However, with a savings of about $25,000 over the equally equipped Cayenne and with much better cabin tech, the FX50S proves that it is a good value for the money.