The Infiniti FX50 Engine and Drivetrain

Infiniti FX50

Infiniti FX50

The Infiniti FX50 features a new powerplant, which makes it debut on this model – an advanced 5.0-liter V8 that is mounted low in the chassis to help lower the FX50’s center of gravity.  The engine design includes twin symmetrical air intakes, microfinished crankshaft, lightweight pistons, super-silent cam drive chains and an electrically driven cooling fan to help optimize performance.

The goals for the development of the FX50’s all-new VK50VE V8 started with outstanding power output – 390 horsepower (287kw) and 500 Nm of torque – a high rev limit, a powerful engine sound from a specially tuned exhaust and improved fuel economy versus the previous generation FX45.  Even small details were evaluated in designing the new engine, including control of oil mist density in crankcase for reduced friction

One of the keys to the new V8’s impressive performance is the adoption of Infiniti’s patented Variable Valve Event & Lift (VVEL) valve control technology, which was first introduced on the Infiniti G37 Coupe.  The VVEL system continuously adjusts valve event and lift amounts, enabling higher fuel efficiency with higher torque and improved emissions over conventional variable valve designs.  The VVEL intake camshafts, which feature continuously variable lift control teamed with a Continuously Variable Valve Timing Control system (CVTC), allow for a 6,900 rpm redline and a high compression ratio of 10.9:1.

The FX50 is comes standard with a new seven-speed automatic gear box with Adaptive Shift Control (ASC) allowing a downshift blip control. FX50’s standard magnesium paddle shifters enable drivers to shift the transmission without releasing their hands from the steering wheel, helping maintain stability for the driver when accelerating or decelerating on winding roads.

Infiniti’s advanced ESP system with Traction Control System (TCS) is standard on all FX models.  ESP adjusts brake pressure and engine torque automatically in understeer, oversteer or slippery road surface situations, helping the driver keep the intended path.  A cancel switch allows the driver to switch off the ESP system when desired.

The FX50 is equipped with Infiniti’s intelligent four-wheel drive system called ATTESA E-TSÔ (Advanced Total Traction Engineering System for All Electronic Torque Split), which uses an advanced torque split control strategy that automatically transfers optimum torque to the wheels according to road and driving conditions.  The system provides outstanding handling due to optimum torque distribution from front to rear (50:50 up to 0:100).  ATTESA E-TSÔ also provides high starting traction performance and smooth, stable acceleration, especially in snow-covered or off-road situations with a 50:50 torque split at standing start.

When the FX50 accelerates from a standing stop, the ATTESA E-TSÔ system provides power to all four wheels.  Once up to speed, if the system’s sensors detect that all-wheel drive is not needed, up to 100 per cent of the power is sent to the rear wheels.  This rear-bias offers better handling balance and improved fuel efficiency.  The system can then divert power forward at any time as traction/road conditions dictate, helping ensure that power always goes where grip is the greatest.

The FX50's dynamic handling is a result of its suspension using light weight and aluminium components in the front and rear to reduce unsprung weight (weight not supported by the springs), helping to improve both ride and handling.

The new double-wishbone front suspension design, similar to that utilized on the Infiniti G37 and G37 Coupé, replaces the previous generation FX’s front strut-type suspension.  The suspension’s upper and lower A-arms help provide superior control of a wheel’s motion, especially when the suspension compresses and extends, providing more travel than the previous strut design.  The net result is a better ride and improved handling.

The FX50’s rear suspension utilizes the multi-link design from the previous generation, refined to weigh less and provide more wheel travel – again for improved ride and handling.  A lightweight, high-strength steel rear subframe is utilized to isolate the FX’s body and its passengers from road noise and vibrations.  Its compact design benefits to room in the rear passenger and cargo area. Large diameter stabilizer bars are utilized front and rear.

The suspension system also incorporates special “dual flow pass” shock absorber technology with rebound springs for responsive yet comfortable ride and firm, tight handling.

The new FX50 includes standard active Continuous Damping Control (CDC) system with special electronically controlled shock absorbers.  Unlike conventional fixed damping force shock absorbers, the suspension with active Continuous Damping Control (CDC) takes the input from a variety of sensors and continuously alters the damping of the shocks to provide optimal ride and handling.  The system features a driver-selectable switch with two settings, “Auto” and “Sport,” allowing the driver to control the shock valving levels.

The FX50’s standard Rear Active Steer system is the first of its kind available in an SUV.  Unlike passive rear steering systems, this design features precise, electronic motor-driven control to turn the rear wheels up to one degree, helping generate a nimble steering response at low speeds and enhance stability at high speeds.  Rear Active Steer moves the FX50’s rear wheels in accordance with the front-wheel steering angle and vehicle speed, rather than passively following the front wheels.  The result is a vehicle that is able to change direction with improved quickness, precision and stability.

The new FX maintains its small turning radius (5.6m) despite its larger wheel and tyre package.  Its engineers focused on improving steering feedback from the advanced speed-sensitive rack-and-pinion power steering system and reduced “play” in the steering mechanism for more direct vehicle response to steering input.

Secure braking performance is provided by the FX50’s 4-wheel ventilated disc brakes with Brake Assist (BA) and Electronic Brake force Distribution (EBD).  The FX50 system features 4-piston front/2-piston rear calipers, similar to those utilized on the new Infiniti G37 Coupé, and large brake rotors (355x22 mm front/350x20 mm rear).  Braking system dimensions and high thermal capacity have been tailored specifically to European driving needs, providing a secure and stable feeling at very high speeds and high deceleration rates.

The FX50 features metallic-finish six-spoke cast-alloy 9.5Jx21-inch wheels made by Enkei.  These wheels are created using a special type of ultra-lightweight casting and are as light as a competitor’s 18-inch wheels.  They are mounted with 265/45R21 performance tyres.

Published 5 March 2008 Melanie Carter

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