Not that the V6 FX35 is a slouch. It also launches impressively from a stop, largely because it has substantially more horsepower and torque than most other six-cylinder SUVs. There's as much grunt as most owners will ever need (even those who like to get racy). Yes, the step up to the V8 is noticeable, particularly when you stab the gas at, say, 60 mph. The FX45 will rocket to 80 at a much greater rate than the FX35. Yet the V8 also chugs fuel at a much greater rate, reducing range anywhere from 25 to 75 miles per tank, according to the EPA's numbers. Both FX models are limited to a top speed of 130.
All the power is managed with sophistication. The FX all-wheel-drive system is tuned for paved roads, and it delivers all the power to the rear wheels until slip is detected. At that point, the system gradually shifts power to the front wheels until the slip is eliminated. That maintains a rearward bias, like a sports car. You can also manually lock the front and rear axles together, a good tactic for deep snow.
The electronic stability control system, which lightly applies braking force to individual wheels when entering a corner too fast, engages so gradually that we couldn't detect when it was working. That means the driver makes the big decisions, such as entry speeds into a corner, and the car decides the little things, such as the optimum braking for each wheel to keep the car doing what the driver wants. Driving an FX45 on the twisty two-lane sports car roads circling the Red and Black Mountains in Southern California, we were able to induce a slight amount of power oversteer while cornering (a satisfying fish-tail effect in the rear), although we were never able to break the mammoth rear tires completely loose.
The FX suspension reflects Infiniti's decision not to make this SUV an off-road vehicle. Off-road ability is enhanced with long travel and compliant suspension tuning, but that same ability compromises handling on winding roads. The FX is tuned for those winding roads. Despite its 7.6 inches of ground clearance, it has no skid plates or underside armor, and the up-down range of movement at its wheels is limited compared to most SUVs.
In tight and sweeping corners alike, the body stays incredibly level, which is the plus side of its stiff suspension. We drove it hard, like we would a sports sedan. Understeer, or the sliding of the front tires that is the default skid condition in most vehicles, begins very gradually when you aim the FX into a corner, and the front wheels continue to push only slightly until you get near its very high cornering limits. Like the 350Z sports car, the FX steering is quick. It doesn't feel as telepathic as a Porsche's, but it doesn't feel light and loose like that in many SUVs, either.
Infiniti claims the FX will brake shorter than rivals from Mercedes, BMW, and even Porsche; we say with a high level of confidence that it can stop with the best. The FX45 remains confident and stable under heavy braking, and that allowed us to drive it very quickly without any scary moments on twisty roads. Yet there is unquestionably a lot of mass underneath, and it needs to be slowed down. A vehicle as heavy as the FX, but also as nimble, can require acute awareness from the driver, because it feels so well-mannered that it's easy to forget how fast it's going and how heavy it is. The best brakes and most sophisticated stability electronics devised can not defy the laws of physics.
As for electronics, the FX offers a new braking trick that until recently was reserved for the most expensive luxury sedans. Called Preview Braking, it comes on FXs equipped with the traffic-sensing Intelligent Cruise Control system. The radar sensors that manage the active cruise control can sense when the FX is closing on an object at a high rate. When they do, the system pre-pressurizes the brake hydraulics before the driver even touches the pedal, and speeds brake activation by fractions of a second when the driver does hit the pedal.
The FX45 can be as much fun to drive as many sport sedans, but the payback is a stiff ride. On the typical stretch of freeway, it isn't a problem. There the FX45 rides smoothly enough, and it feels relaxed. It cruises at 80 mph in fifth gear with the engine turning a low, quiet 2800 rpm. The cabin is quiet and isolated enough for delicate cell phone conversations, but it's not the serene environment of a true luxury sedan.
Unless you need to boast about the most power or the absolute best acceleration, the FX35 may be the preferred choice, without the sport package. It's still plenty nimble and quick, and fun to drive. But its suspension is slightly more compliant, more comfortable in most situations, and its higher profile tires take some of the crack out of bumps and expansion joints. Overall, the FX35 rides smoothly, but the suspension is still on the firm side and the ride gets a little bumpy on rough streets at low speeds. Next Page