The five-second Jeep

The Grand Cherokee is again hunting scalps; specifically the scalps of the supercharged Range Rover Sport and the BMW X5 4.8i. Jeep's luxury SUV -- in the guise of the upgraded 6.1-litre V8-powered SRT8 variant -- is stalking its premium/performance competitors.

Producing 313kW of power and 569Nm of torque, the Grand Cherokee SRT8 can reach 100km/h from a standing start in the low five-second range. Jeep claims the high-performance variant is the fastest SUV available in Australia for less than $100,000.

The '08 model year SRT8 joins the Grand Cherokee range in time for a cosmetic and specification upgrade, but in addition, the SRT8 brings its own distinct identity to market.

A unique front apron provides airflow benefits to cool the engine and brakes, while reducing both lift and drag at the same time. At the rear, the lower apron features a centre cut-out for the dual four-inch exhaust outlets. Self-levelling HID (xenon) headlights are fitted as standard to this variant.

Inside the cabin, Jeep designers have specified softer plastics and leather trim in a dark slate grey tone with coordinating stitching. Deeply contoured front seats are also electrically adjustable and trimmed with suede inserts which Jeep claims will help to hold the occupant in place during cornering.

The instrument binnacle and centre fascia have been redesigned with aluminium highlights for the fascia, and the instruments -- including a 300km/h speedometer -- featuring a blue accent, new graphics and higher-spec finishes for the bezels. Chrysler's MyGIG information and entertainment system is standard in this vehicle and integrates DVD-based satellite navigation and a reversing camera for 2008.

Jeep's engineers have developed a unique transfer case for the SRT8 (the MD146 SRT), matching the front half of the case from the Jeep parts bin to a rear half that is built for heavier-duty applications. Most of the torque is transmitted to the rear wheels in ordinary driving, with a torque split of between five and 10 per cent diverted to the front wheels. More torque can be redirected to the front wheels in adverse conditions and the system will transfer as much torque as necessary in these circumstances.

The engine powering the Grand Cherokee SRT8 is the same engine also seen in the Chrysler 300C SRT8 and is basically a bored version of the standard 5.7-litre HEMI V8. Chrysler also upped the compression ratio to 10.3:1 and reworked the cylinder heads, inlet and exhaust systems.

The engine drives through a five-speed sequential-shift automatic which has been upgraded for the task of transmitting the engine's torque to the road. Shift points have been revised and the transmission is equipped with an upgraded torque converter.

Along with changes to the drivetrain, Jeep engineers have fitted specific dampers, anti-roll bars, revised bushes and springs for higher-speed driving and the improved front suspension knuckles cope better with the higher braking and steering loads mustered by the SRT8 model.

On the subject of brakes, the SRT8 is fitted with four-piston Brembo brake calipers, in black. The ventilated front disc rotors measure 360x32mm and, at the rear, the ventilated rotors measure 350x28mm. 20-inch alloy wheels roll on 255/45/20 front tyres and 285/40/20 rears, with the wheels measuring nine inches in width at the front and 10 inches at the rear.

As well as Jeep's ERM (Electronic Roll Mitigation), the SRT8 features such safety features as ABS/ESP, traction control, multi-stage airbags, side-curtain airbags, Brake Assist, force-limiting seatbelts with pre-tensioners, headrests for all outboard seats, knee protection, reverse parking acoustic guidance, reversing camera, rain-sensing wipers, Enhanced Accident Response System (EARS telematics) and tyre-pressure monitoring. 

Convenience features fitted include auto-up/down front electric windows, remote central locking, hands-free Bluetooth mobile phone connectivity.

Jeep dealers will begin retailing the new model year SRT8 this month, at a price of $89,990 -- a hefty rise from the previous model's $85,990.

To comment on this article click here