The New Jaguar XKR

Jaguar XKR Coupe and Convertible

In November 2006 Jaguar launched the much anticipated 2007 XKR supercharged version of the XK.

Engine and Transmission

The heart of the new XKR is a supercharged version of the 4.2 litre AJ-V8 engine, producing 420 bhp at 6,250 rpm and an impressive 413 lb-ft of torque, accelerating the XKR from zero to 60 mph in just 4.9 seconds (5.0 for the convertible) and on to an electronically limited top speed of 155 mph.

Compared with the previous XKR, the new model produces an additional 20 bhp, and 36% more torque than the normally aspirated XK.

Not only does the the new XKR produce more power and torque than its predecessor, but combined with a significantly stiffer and lighter aluminium monocoque body structure, the power to weight ratio is improved by 12% and 7.7% for the torque to weight ratio.

The increase in power and torque is down to two significant changes to the engine. The air intake has been significantly enhanced thanks to the use of twin air inlets, and a Variable Inlet Camshaft Timining (VICT) system is used for the first time on the XKR.

The VICT system is controlled by the Engine Management System (EMS) which recieves engine speed, throttle position and oil temperature data from its sensors and determines the correct inlet camshaft timing by continuously referring to a digital three-dimensional map. The ENS then transmits the appropriate signals to two solenoids that control the degree of hydraullic force provided to the valve actuators.

The New XK has already been priased for its acoustic quality, remaining unobtrusive and relaxed at modest speeds, but producing an unmistakeable V8 soundtrack when worked hard. On the XKR, the presence of supercharger whine threatened to dominate the acoustic character and mask the underlying sound quality. However, through enhancements to the acoustic pack, the spercharger noise has been reduced by 5dB compared to the previous XKR eliminating any potential issue.

This approach to acoustics allowed engineers to concentrate on using the exhasut sytem to dleiver the best possible sound quality character, accomplished through the use of the XKR’s Active Exhaust which varies the flow of exhaust gases through the car’s main silencer. The previous XKR had always been criticised for its “peashooter” exhausts, so this was a much needed improvement.

Like the XK, the XKR uses Jaguar’s new sequential change gearbox but with revised ratios to suit the increased performance of the engine. Having driven the XKR around Goodwood circuit, this gearbox is without doubt one of the most impressive features of the car. Gear changes are lightening fast and seemlessly smooth. Under hard braking the EMS automatically blips the throttle to ensure smooth down changes. Gear change paddles are fitted to the steering wheel as standard - another improvement over the previous XKR. With three various gearbox modes for the driver to choose from, the transmission can match the driver’s style without hesitation.

Chassis, Suspension and Brakes

To ensure optimum sporting ride and handling, the XKR’s springs and dampers are uprated compared to the XK. The Servotronic steering system has been tuned both mechanically and electronically to give the sterring more weight and even greater response.

Because of the inherent strength and torsional rigidity of the chassis, and the addition of a rear suspension brace engineered to acommodate the significant increase in rear spring rate, the XKR coupe and convertible have the same dynamic settings.

The Computer Active Technology Suspension (a two stage adaptive damping system that ensures the optimum balance between ride and handling) and new switchable Dynamic Stability Control with Traction Control System (Trac DSC) have also been recalibrated to complement the additional power of the supercharged engine.

New larger ventilated brake discs at the front (355mm x 32mm) ensure even better braking perforance for the XKR. The brake calipers are no longer Brembo though, whilst not the most attractive caliper, are more than adequate to reign in the power from the engine. Braking performance has been improved by about 30% over the previous XKR.

Design Attributes

The XKR has incorporated some subtle, yet interesting and effective styling changes compared with the XK.

At the front the fog lamp housings are different to the XK and are colour key finished to match the exterior paintwork of the car. There’s no chromium plating on the XKR, instead items are aluminium finished like the front wing side power vents, the rear “signature blade” to the boot lid and other exterior trim. The bonnet louvers are of an entirely new design and also alloy finished for good effect. The alloy finish continues to the new mesh frilles for the upper and lower frontal areas of the car.

The quad exhaust system fitted to the XKR has necessitated a revised lower bumper bar design at the rear. The XKR wheels are unique: either the 19" Jupiter design or the optional 20" Cremona split rims.

Internally the XKR features a unique sports seat design with additional lateral support for both the driver and front seat passenger, with an ‘R’ badge on the headrests, tachometer, steering wheel and feat selector. The design of the standard aluminium interior trim is also unique to the XKR, featuring a ‘weave’ pattern from the Advanced Lightweight Coupe design concept that was first shown at the 2005 North American International Auto Show.

XKR customers can also specify the Luxury Sports interior option which features softgrain leather on the adjustable seats, instrument panel, door trim and centre console.

Overall Impression

Living up to Jaguar’s perpetual promise of quality, style, speed, and refined definition, the XKR is no exception. For the newest member of the Jaguar family, she comes onto the scene with explosive style and grace. She has been modeled from bumper to bumper to reflect Jaguar distinct performance qualities while being special enough to outperform the rest of the Jaguar family. Rarely does a car burst into the limelight with so little criticism and so much brilliant praise. But after all, it is a Jaguar.

Jaguar XKR
Jaguar XKR Rear
XKR Convertible
Jaguar XKR Coupe
Silver Jaguar XKR Coupe