The QX50 offers an optimal balance of stability, comfort and ride control – quiet and refined, while also rewarding and giving confidence to the enthusiast driver.
The QX50’s new platform enables the car to resist flex and vibration, and allows the front and rear suspension, steering and brake components to perform at their best.
An all-new MacPherson Strut front suspension system delivers immediate responses during spirited driving, with geometry set up to also provide high levels of straight-line stability and ride sophistication. Early suspension prototype components were modelled and validated with 3-D printing, the first time INFINITI has used the technology. 3-D printing enabled the rapid creation of new parts, reducing the complexity of development.
The QX50’s new damping control system maximizes body control and ensures a comfortable ride by isolating vibrations and reducing unwanted body motions. The system, fitted to the struts, uses a floating valve in the dampers.
It is tuned to provide greater control and reduce the level of elasticity in driver inputs – the ‘lurching’ delay between the driver turning the wheel and the car reacting – while enabling a greater degree of compliance and shock absorption at wheel level. Under cornering, the valve adds greater damping force to reduce body roll and aid immediate handling responses. At steady straight-line speeds, a reduced level of damping force aids cruising comfort.
All-new brakes are engineered to deliver comfort and responsiveness, and provide confident braking in all conditions. The linear stroke of its brake pedal provides a reassuring level of resistance, at any point in its travel. The brake booster is tuned to prevent the car grabbing at the brakes with light pressure on the pedal, applying maximum brake force if the system detects a firmer push on the pedal.
The QX50 is fitted with ventilated disc brakes on both axles, with larger front brakes than the current QX50 (growing 10 mm in diameter to 330 mm). The brake booster is newly designed, featuring a tie-rod system which reduces the need for higher brake pedal pressure.
The QX50’s wheels are fitted with new run-flat tires, striking a balance between design, practicality and refinement. The application of run-flats enables the fitment of low-profile tires around the 20-inch wheels, while special reinforced rubber sidewalls allow the tires to work with reduced air pressure for up to 93 miles (150 km). This gives owners the peace of mind that they can drive to a tire fitter to replace a punctured wheel, and eliminates the need to carry a spare tire, freeing up additional trunk capacity.
The new QX50 employs a range of advanced handling technologies to place the driver in complete control. Customers can specify their QX50 with either Intelligent All-Wheel Drive (AWD) or the standard front-wheel drive (FWD) drivetrain.
The optional Intelligent All-Wheel Drive system offers all-season safety, providing optimal handling performance and maximum driver confidence in variable conditions. The drivetrain offers two-wheel drive efficiency, with all-wheel traction when the driver requires it.
The QX50’s AWD drivetrain constantly monitors traction levels and wheel spin and can send up to 50% of the engine’s torque to the rear wheels to maintain traction. If the extra rear-wheel traction isn’t required, the drivetrain defaults to front-wheel drive for maximum efficiency. When accelerating from a standstill, the system automatically reverts to AWD power delivery, with a 50:50 front-to-rear torque split.
The AWD system also features two new elements to its Vehicle Dynamics Control (VDC) system. Active Brake Limited Slip enables wheels to brake individually and isolate the delivery of torque to those wheels with the most grip. Active Trace Control provides braking to individual wheels to limit understeer when cornering.
The QX50 is sold as standard with front-wheel drive, a system engineered to deliver the same handling characteristics under most conditions as AWD models. The FWD drivetrain constantly monitors traction levels at the front axle and keeps wheel spin in check. FWD models are equipped with VDC as standard, offering the same Active Trace Control system as AWD models, to ensure confidence-inspiring handling. The rear suspension is revised to accommodate the lighter weight over the rear axle.
DAS is the world’s only digital steering system, and the fourth generation features updated software for the QX50 – the first SUV and first front-wheel drive application of the system. DAS replaces a mechanical steering column with high-speed electric motors and sensors, with the steering instead controlled and enhanced digitally. The system places the driver in total command, and is key in realizing the QX50’s ProPILOT Assist functions.
The DAS system has been tuned to provide greater customizability in the QX50, with less negative steering and road surface feedback. DAS is programmed to provide smooth steering and more direct responses, while enabling easy maneuverability. DAS eliminates the need for mechanical parts, instead employing digital components to improve feel and feedback. The electronic connection gives the driver instantaneous steering responses, for a linear and secure driving experience.
Different driving modes can be selected to adapt steering responses and steering effort. This means the QX50 can track straight and true at a steady highway cruise, with minimal steering input required for a relaxing drive. It can then enhance the car’s handling upon request, empowering the driver to steer more quickly and accurately than a conventional steering system.
The Rack EPS system is a rack-and-pinion configuration, supported by an electric motor. It offers a natural build-up in the level of steering effort required from the driver as speeds increase, while enabling measured and linear steering responses at low steering angles.
Both steering systems are adaptive, empowering drivers to tailor steering characteristics to their individual preferences via the Drive Mode Selector (DMS).
The DMS allows the driver to select the driving mode that best suits their preferences and present road conditions. Empowering the driver to customize their driving experience, DMS adjusts engine torque output, transmission shift points, steering ratios and steering effort in each mode. In every model, drivers can choose from four different driving modes: Standard, ECO, Sport, and Personal.
Standard is suitable for every-day driving, with default engine output, transmission and steering settings. ECO mode lowers the power output slightly for improved fuel economy, with more relaxed throttle responses. Meanwhile, the CVT adopts longer gear ratios, lowering engine speeds for greater efficiency. This mode maintains default steering settings.
Sport mode enables more immediate throttle responses, and adjusts the engine output to deliver higher power and torque. The CVT is programmed to allow the engine to reach its highest power output before it shifts, while greater steering effort is required of the driver, with the ratios adjusted for more immediate steering responses.
Personal mode empowers the driver to pick their own settings. The engine and transmission can be set to Sport, ECO or Standard settings, while steering effort can be set to Sport or Standard. Furthermore, owners of DAS models can tailor steering responses to Default, Dynamic or Dynamic+, with Dynamic+ offering the most immediate reactions to driver inputs. The DMS gives drivers of all models the option to turn off Active Trace Control.
The QX50 features a pair of active sound control technologies: Active Noise Cancellation (ANC) and Active Sound Enhancement (ASE). ANC reduces noise to give the QX50 one of the quietest cabins in its class. It uses two microphones to identify undesirable low-frequency engine noise (‘booming’), then neutralizes it by playing opposing sound waves through the door speakers. This creates a relaxing, refined atmosphere that enables and encourages conversation among occupants – or lets them listen to music more clearly.
ASE adds to the driving experience by enhancing the sound of the QX50’s performance. Noise cancellation technology provides a quiet platform from which to build up a more pleasant range of sounds in the cabin. ASE enhances the engine note through the speakers, augmenting certain engine noise frequencies under acceleration. The technology provides an acceleration sound that matches the driver’s intentions for and expectations of the engine.
The INFINITI QX50 has been subjected to a robust global testing regime, with 600 late-stage prototypes tested on roads and tracks all around the world in extreme weather conditions and in locations that included switchback mountain passes, arid deserts, congested urban hubs and high-speed highways.
The new VC-Turbo engine was a particular focus for testing teams, following the unit’s 20-year development process. INFINITI has worked on the unique multi-link technology since 1998 to validate reliability, testing more than 200 physical engine prototypes. This has included over 30,000 hours on test beds – equal to 5,000,000 kilometers of testing and development – and 3,000,000 kilometers of equivalent road testing. Testing of INFINITI’s new engine has also included verification at the hands of the Renault Sport Formula One team. INFINITI drew on the motorsport team’s expertise in material dynamic motion analysis to validate reliability under extreme conditions.