Brian Joss – The Jeep Grand Cherokee Trackhawk built in Detroit, Michigan, and injected with a supercharged 6.2-litre V-8 engine has been transformed into one of the most powerful and quickest SUVs yet.
Jeep said The breakthrough supercharged engine is designed and manufactured using only the strongest and most durable materials. Its cast iron block features water jackets between the cylinders for optimal cooling. A forged-steel crankshaft with induction-hardened bearing surfaces is so strong it can withstand firing pressures of nearly 110 bar (1,600 psi) – the equivalent of five family sedans standing on each piston, every two revolutions. The unique, specially tuned crankshaft damper has been burst tested to 13,000 rpm.
The 2,380cc per revolution supercharger includes integral charge-air coolers and an integrated electronic bypass valve to regulate boost pressure to a maximum of 80 kPa (11.6 psi).
The supercharger is sealed for life with premium synthetic oil, uses a drive ratio of 2.36:1 and has a maximum speed of 14,600 rpm. The supercharger drive system’s one-way clutch de-coupler improves refinement, while allowing for precisely the kind of powerful sound certain to captivate drivers.
The large-nosed crankshaft drives a high-flow gerotor oil pump, which feeds a lubrication circuit that includes eight high-flow piston-cooling jets. A high-capacity oil/air heat exchanger, mounted in the front of the Jeep Grand Cherokee Trackhawk, mitigates oil temperatures when driving conditions are harshest, such as on the track.
A new fuel delivery system, featuring two high-flow, multi-mode pumps, matches the high-performance demands of the engine.
The standard TorqueFlite eight-speed automatic transmission delivers improved shift response, quality and consistent performance and drivability.
The transmission software takes into account variables such as engine torque gradients, kick-down events, longitudinal and lateral acceleration, grade changes, friction detection and downshift detection to determine the appropriate shift map.
The SUV is equipped with the Jeep Quadra-Trac on-demand four-wheel-drive system, which includes an electronic limited-slip rear differential and a single-speed active transfer case. The new, full-time active transfer case uses forged steel chain sprockets and a wider chain for added strength and durability.
A strengthened rear drive shaft connects to a new, stronger rear axle. The differential features a revised housing design, revised ring-and-pinion tooth geometry and new four-point axle mounting scheme for better load distribution, additional torque capacity and overall durability. Launch Control, fitted as standard, optimises the SUV’s performance by coordinating the engine, transmission, driveline and suspension for consistent straight-line acceleration.
The Selec-Track system uses performance-tuned software to pre-configure and distinguish the five dynamic modes, including: Auto, Sport, Track, Snow and Tow, enabling drivers to choose a vehicle setting that ideally meets their requirements and ambient conditions. The drive modes separately control the four-wheel-drive system, transmission, paddle shifters, suspension and the electric power steering.
Dynamic drive mode configurations include: Auto – Automatically adapts to any condition; uses a 40-percent front/60-percent rear torque split, Sport – Transmission shift times are reduced by 50 percent versus Auto Mode; stability control, four-wheel-drive and steering systems are set for typical enthusiast driving style; paddle shifters are enabled and suspension is tightened up without increasing impact harshness to deliver increased vehicle performance capability over Auto Mode; uses 35/65 torque split; Track – Transmission shift times are reduced 68 percent versus Auto Mode to
160 milliseconds; stability control, four-wheel-drive and steering systems are set for ultimate track performance; paddle shifters are enabled and suspension is set to full firm to deliver maximum vehicle performance capability on smooth, dry surfaces; uses 30/70 torque split; Tow – Alters torque delivery off the line for greater smoothness and adjusts suspension to combat pitch and yaw to deliver maximum towing performance: uses 60/40 torque split and , Snow – Maximizes traction to deliver optimized performance on snow and ice with reduced engine horsepower; uses 50/50 torque split The Trackhawk also features a Custom Mode that allows the driver to personalise the vehicle’s performance with a selectable driving experience offering a multitude of vehicle system combinations.
The Jeep vehicle lineup consists of the Cherokee, Compass, Grand Cherokee, Renegade and Wrangler.
CAPTION: Quickest yet: The Jeep Grand Cherokee Trackhawk. Picture: Quickpic