|Saturday, 17-Nov-2018 13:03:10 CET|
Editor/Photographer : Mark Charles
cars turn heads and raise pulses like the Jaguar XK – and now there is a
new generation of this thrilling luxury sports car, enhanced by major powertrain
improvements and a host of new features.
When the XK8 was introduced in 1996, it set new standards in the luxury sports car market. Two years later, the supercharged XKR lined up alongside, raising levels of driving excitement, style and performance still further.
Now, for the 2003 model year, comes an extensively revised successor to the beautiful coupe and convertible XKs that have so delighted owners and bystanders alike.
The classic XK style does not change with this new generation, the revised styling details inside and out providing a subtle variation on the theme rather than a new look. That can come as no surprise with a car that is universally regarded as an example of automotive beauty, and to many eyes has matured to become even more attractive than it was when launched.
But under the skin it is a very different story. Larger, more powerful 4.2-litre V8 engines significantly increase the performance of the XK. A world-leading six-speed automatic transmission ensures that drivers are able to make the most of the power when they choose, yet be equally at ease in urban traffic. And a portfolio of enhanced electronic and other equipment options – focusing on safety, comfort and drivability –make the new XK even better to drive than the original.
“The engineering changes made to the XK for 2003 are substantial and significant. The extensively revised powertrain, with the new, larger capacity 4.2-litre engines and six-speed automatic transmission, contributes to an improvement in every aspect of the driving experience.”
RUSS VARNEY, CHIEF PROGRAMME ENGINEER
At the heart of the revised XK range are two new 4.2-litre V8 engines, one naturally aspirated, the other supercharged. An evolution of the now-familiar 4.0 - litre AJ-V8 engine that was introduced in the first XK8, the larger capacity and subsequent increase in power and torque make the performance of the XK even more scintillating. Coupled with the more muscular engine is the state-of-the-art, electronically-controlled, six-speed automatic transmission that made its Jaguar debut in the new S-TYPE R. Built by ZF, it is the first example of a ‘stepped’ (as opposed to CVT)six-speed automatic transmission.
Every variant – naturally aspirated XK8 or supercharged XKR, coupe or convertible – delivers even more effortless performance, greater refinement and craftsmanship, improved functionality and enhanced drivability, reaffirming the unique balance that makes the XK the perfect combination of true sports car and luxurious grand tourer.
A familiar personality, with major developments
The 2003 model year XK benefits from a broad programme of improvements – there are some 900 part number changes –underlining the fact that while its appeal may be timeless, development of this sporting Jaguar has certainly not stood still. Now with 300bhp (DIN)in the normally aspirated XK8, or a full 400bhp (DIN)in the supercharged XKR, the XK is now even more impressive than the car that has earned the model its reputation. In fact, the 400bhp XKR shares with the latest S-TYPE R sports saloon the distinction of having the most powerful series production engine in Jaguar’s history.
The package of advances over the previous generation XK also encompasses the latest electronic driving aids. Covering areas from handling and braking to ‘intelligent ’cruise control, these include Dynamic Stability Control and Emergency Brake Assist as standard across the XK range, and Jaguar’s innovative, traffic-sensing ACC (Adaptive Cruise Control)as an option.
And while performance is unashamedly a core value of the XK, safety also remains at the heart of the equation. The XK continues to offer industry leading features across the entire range, including Jaguar’s A.R.T.S.Adaptive Restraint Technology System (with the world’s first ultrasonic occupant sensing to control airbag deployment), and the option of ACC now enhanced with Forward Alert, an additional feature that audibly warns drivers of slowing traffic ahead.
“One of the core values of the new-generation XK is the purposeful use of relevant electronic technology to significantly enhance driving enjoyment and safety.”
DICK ELSY, DIRECTOR PRODUCT DEVELOPMENT
Subtle styling changes for a sophisticated market
Externally, the changes to the XK are subtle, which is no surprise given its acknowledged sensuous beauty. The styling has always been about more than fashion and those powerful, assertive curves are still one of the XK’s strongest selling points. Jaguar research shows that customers see the car as stylish, beautiful and totally individual, with a character quite distinct from any rival.
Where the XK has visually changed, the actions have been taken to ‘freshen ’rather than reinvent. The cars sport new badging, and there is a choice of four new exterior colours, a range of new interior trim combinations and three new wheel designs. The introduction of Xenon headlights – as standard on the XKR and optional on the XK8 – gives the front of the car a distinctive new look.
The latest R Performance range of options (available on both XK8 and XKR)includes unique Recaro seats, high performance Brembo brakes (now standard on the XKR)and a package of interior details with sporty aluminium or leather finishes. A handling package that uprates suspension and steering is available on coupe models only.
“More than ever,the XK represents the art of performance and remains the epitome of Jaguar luxury sports car values.”
LAWRENCE THOMAS, XK BRAND MANAGER
THE NEW-GENERATION JAGUAR XK: AT A GLANCE
· Subtle exterior styling changes only – including new Xenon headlights and new badging – but an extensive programme of major mechanical revisions.
· Two new AJ-V8 engines in naturally aspirated and supercharged guises,now with larger 4.2-litre capacity (previously 4.0-litre).
· More power and more torque – 300bhp (DIN)and 420Nm (310lb ft)for the XK8, a mighty 400bhp (DIN) and 553Nm (408lb ft)in the case of the supercharged XKR.
· The XKR coupe reaches 60mph from standstill in 5.2 seconds (0-100km/h in 5.4 seconds)with the XK8 taking 6.1 seconds (0-100km/h in 6.4 seconds). Maximum speed on all XK models remains electronically limited to 155mph (250km/h).
· Greater mid-range punch and effortless acceleration, aided by state-of-the-art six-speed ZF automatic · transmission.
· Jaguar’s classic J-Gate shift retained,offering automatic or manual control modes, with improved feel · and function.
· Race-bred Brembo brakes now standard on XKR, optional on other models.
· ‘Intelligent ’use of advanced technology, designed to enhance the driving experience,not just the equipment list. This includes adoption as standard across the range of Dynamic Stability Control (DSC), Emergency Brake Assist (EBA)and Cruise Control. Adaptive Cruise Control (ACC)is an option,and now features Forward Alert,an audible driver warning system that senses and responds to slowing traffic ahead.
· Features Jaguar’s world-leading Adaptive Restraint Technology System (A.R.T.S.)with world ’s first Ultrasonic Occupancy Sensing function.
· Automatic headlights-on and rain-sensitive wiper functions; Xenon headlights with automatic self-levelling standard on XKR, and a cost option on XK8.
· Electrically adjustable steering column with entry/exit mode now standard on all models (memory optional). New equipment options include upgraded DVD-based navigation system and electrochromatic mirror with compass.
· Range of new alloy wheel designs available as options.
· Four new exterior colours: Jaguar Racing Green, Ebony, Midnight and Adriatic Blue.
· New interior trim options include ‘contrast ’ finishes that feature Warm Charcoal contrasted with Heritage Tan or ranberry on sports style seats.
· R Performance options offer top levels of sporting luxury.
· The XK8 and XKR range has become the fastest selling sports car in Jaguar history with more than 70,000 sold worldwide since launch.
HISTORY AND MARKETPLACE
“The underlying character of the XK can still be defined in four words: powerful, original, sensuous and exciting. It continues to offer a unique combination of style and performance and emotional involvement that appeals strongly to very discerning customers.”
LAWRENCE THOMAS, XK BRAND MANAGER
The XK has always had all the ingredients it needed to be very special. When the original XK8 was unveiled in 1996, this elegant high performance sports car set new standards in the luxury sporting market. Succeeding the venerable XJS, the front-engined, rear-drive XK8 was Jaguar’s first new sports car for a generation. It set new records for Jaguar in terms of the time taken to bring a new model-programme to market, and achieved new levels of quality and functionality. The XK8 also set sales records, rapidly becoming the fastest selling sports car in Jaguar’s history, and in doing so won numerous awards around the world.
In 1998, an even more dramatic model was unveiled – the supercharged XKR. With still more impressive performance, the R added another dimension to the XK story. Two very special editions followed, with the Silverstone celebrating Jaguar’s entry into Formula 1, in 2000, while in 2001 the XKR 100 celebrated the centenary of the birth of Jaguar founder Sir William Lyons. By then the XK had become an icon and to date, sales have exceeded 70,000 worldwide.
A strong, balanced character that appeals to discriminating buyers
The XK’s unique appeal is rooted in the balance it provides between styling,luxury,comfort and refinement, together with high levels of performance backed by superb driving dynamics. Beyond that, it is also much admired for the tangible craftsmanship evident in the car,and the contemporary use of traditional trim materials. These attributes are taken to new heights in the 2003 model year XK.
Performance with luxury – the winning combination
The XK has established a niche for itself as the sporting car of choice for an enthusiastic market of successful, style-conscious individuals who have worked hard to achieve their rewards and are still young enough to enjoy them. Typically, XK buyers desire a car with real performance and involving driving dynamics, but are mature enough to demand considerable luxury, refinement and a ‘grown-up ’character. Jaguar research reveals them to be very interested in the latest technology, particularly when it enhances the driving experience.
With the naturally aspirated XK8 now drawing on 300bhp (DIN)and the supercharged XKR having up to 400bhp (DIN)available, the performance credentials of the XK are even stronger. A maximum speed (electronically limited) of 155mph is arguably less impressive than the acceleration on offer. In coupe form, the XK8 is capable of 0-60mph in 6.1 seconds, while the supercharged XKR can achieve this sprint in just 5.2 seconds. With more power and torque than their predecessors and the added benefit of six ratios instead of five in the automatic transmission,all new-generation XK models deliver livelier – and yet effortless –performance.
In conjunction with this, the XK offers the taut ride and handling and precise steering that are essential in a sports car. Every version also has powerful ventilated disc brakes all round, while the new XKR adopts even more impressive, race-developed Brembo brakes as standard equipment. In short, the latest XK is truly engineered to perform.
New engines and transmission transform the XK – from superb to even better!
The adoption of all-new powertrains is the biggest change in the new-generation XK. The latest 4.2-litre AJ34 version of Jaguar’s outstanding AJ-V8 engine is coupled to an industry - leading six-speed automatic transmission. Driving through a rear axle with a new differential that is fine-tuned to maximise the power and torque characteristics of the new engine, the result is an exceptional powertrain.
Both engine and transmission are very similar to those recently introduced in the S-TYPE range, but have beenspecifically engineered for use in the XK.
The new 4.2-litre V8 in detail
“We considered a number of bore and stroke configurations before deciding on the engine capacity we needed in order to deliver the performance we wanted. The increase to 4.2-litre may not seem that much, but it has allowed us to achieve all of our goals.”
RON LEE, GROUP CHIEF ENGINEER
Jaguar’s new AJ34 family of engines was developed at the Jaguar Engineering Centre at Whitley in Coventry. Designed to deliver more performance, better economy and improved refinement when compared with the original AJ28 AJ-V8 from which it has evolved, the AJ34 retains the same compact, 90 degree V8 dimensions but is structurally even stiffer.
Capacity is increased to 4196cc, with bore and stroke now 86.0 x 90.3mm. With a ribbed block and cylinder heads, the engine is very light but extremely strong, its best-in-class stiffness minimising radiated engine noise and increasing mechanical reliability. The four-throw, six balance-weight crankshaft is supported in five main bearings and the connecting rods feature fracture-split big-end journals, for strength with light weight and perfect balance. Mechanical refinement is improved, reducing engine-generated noise and vibration even further.
The four chain-driven overhead camshafts are ‘rifle-drilled ’ to save weight and improve performance. Revised camshaft drive sprockets and finer-pitch inverted-tooth chains further reduce the already-low radiated noise levels and mechanical load.The camshafts operate four valves in each pentroof combustion chamber, and direct-acting aluminium bucket tappets need no adjustment for the life of the engine.The unusually narrow 28 degree valve angle benefits both combustion chamber shape and overall packaging.
The new 4.2-litre V8 benefits from continuously Variable Camshaft Phasing. A hydraulic actuator on each inlet camshaft is operated by a pair of electronically-switched oil-pressure control valves, activated by the engine control module – which contains maps of engine speeds and loads. The system continuously adjusts the phasing of the camshafts, from maximum advance to maximum retard in less than 0.7 seconds. The inlet timing is therefore optimised at all times,according to load and other conditions, to produce faster engine response and optimum performance at all engine speeds – with more torque at low speeds and maximum power at high speeds. It has the added advantage of providing internal exhaust gas recirculation, reducing NOX emissions by slowing down the combustion rate and reducing HC emissions by reburning the exhaust gases.
With exactly 300bhp (224kW DIN)at 6000rev/min and 400bhp (298kW DIN)at 6100rev/min, the new engines are respectively 3.5 and 8.1 per cent more powerful than their predecessors.
The improvements in torque are equally significant. Maximum torque for the normally aspirated 4.2-litre V8 is now 420Nm (310lb ft)at 4100rev/min, while the supercharged engine peaks with 553Nm (408lb ft)at just 3500rev/min. That said, ‘peaks ’ is hardly the way to describe the torque delivery from the supercharged 4.2—litre engine. The torque curve for the new V8 sits significantly above the equivalent curve for the previous 4.0-litre engine, but once again it is impressively flat across the whole of the engine’s usable rev range. That includes at least 86 per cent of its peak torque all the way from 2000rev/min through to maximum engine revolutions.
To match the increased output and the increased mechanical and thermal stresses that supercharging imposes, the new XKR V8 has stronger pistons,forged from single billets of aluminium alloy. It also features oil jet cooling on the underside of the piston crowns, for maximum cooling and minimum distortion.
High performance and high efficiency
Maximum road speed may be electronically limited to 155mph, but the combination of increased torque across the rev range and six speeds rather than five, make the XK ’s mid-range performance even more flexible –and powerful – than ever. In both versions of the engine, a portfolio of changes beyond the increased capacity and revised architecture contribute to increased power output and increased efficiency. Branched exhaust manifolds are used to allow tuning of the primary length of the exhaust manifolds and pairing of the manifold branches of appropriate cylinders, which helps to improve volumetric efficiency and so engine performance.
The original AJ-V8 featured an innovative composite-moulded air intake system, with integral fuel rails for the ultra-accurate positioning of the injectors relative to the cylinder heads. This is improved with the introduction of new multi-hole injectors to refine the spray pattern in the combustion chamber, increasing power while aiding economy and therefore emissions.
Emissions are further reduced by increasing ignition retard during cold starts, minimising exhaust catalyst warm-up time and reducing the need for a richer fuel mixture. Close-coupled catalytic converters in the five-box stainless steel exhaust system begin to operate within 30 seconds of start-up. Exhaust manifolds with low thermal inertia further reduce warm-up time and the new V8 retains Jaguar’s patented low-volume, high-velocity cooling system. This uses minimum volumes of coolant in carefully designed cylinder head and block cooling passages, again helping the 4.2-litre engine achieve a very fast warm-up time (less than four minutes in a simulated urban test cycle), to the benefit of both economy and emissions.
The Electronic Management System controls all primary engine functions including fuel delivery, ignition timing and throttle control, plus secondary systems such as variable cam phasing, exhaust gas recirculation, fuel purging, knock control and cooling fans. Its ‘drive-by-wire ’ function operates the engine’s throttles electronically in instant response to the driver’s positioning of the throttle pedal and incorporates a ‘limp home’ facility, which in the unlikely event of a system failure allows the car to be driven to safety or assistance, at a restricted speed. The hydraulically-tensioned camshaft chains and the seven-rib spring-tensioned poly-vee belt which drives the alternator, power steering, water and air conditioning pumps are maintenance free, with a service life in excess of 100,000 miles (160,000km).
The new 4.2-litre XKR engine uses a rotor-type Eaton supercharger, belt-driven from the front of the crankshaft. It also features two industry firsts on a production car supercharger – helical rotor gears for low noise, and coated rotors for increased efficiency. These innovations have contributed to a supercharger speed five per cent greater than that of the supercharger in the 4.0-litre engine, further benefiting volumetric efficiency.
THE AJ-V8 STORY
The AJ-V8 engine was Jaguar’s first ever V8, and only the fourth series production engine type in the company’s history. Following the classic twin-cam in-line sixes, the ground-breaking V12s and the second-generation all-alloy 24-valve AJ6 sixes, the engine made its public debut in 1996 in the XK8. In 1998, the new XKR adopted Jaguar’s first supercharged production V8, which was at that time newly introduced in the XJR sports saloon. The strengths of supercharging were already proven with the powerful and refined XJR6 saloon and the AJ-V8 engine, with its lightweight but extremely stiff cylinder block, provided the perfect platform for a forced induction engine that delivered a very special combination of power with refinement. As a compact,lightweight, all-aluminium, four-cam, 32-valve V8 with programmable variable valve phasing, the AJ-V8 quickly earned a reputation for three Jaguar signature characteristics –high performance, smooth power delivery and exceptional mechanical refinement. It offered a best-in-class specific power output of 72.5bhp/litre (54kW/litre)and a superb power-to-weight ratio. Even in its original form the AJ-V8 was known for its outstanding flexibility, with more than 80 per cent of peak torque available all the way from 1400rev/min to 6400rev/min. With its class-leading power peak of 290bhp, the AJ –V8 made the first XK8 not only a genuine performance car, but one with real depth. The new 4.2-litre V8 engines mark the first major change from the original AJ-V8.Like the 4.0-litre engine, the new AJ34 will be built at the Bridgend Engine Plant in Wales.
Lightweight construction, heavyweight performance
The original AJ-V8 weighed only 200kg and was the lightest engine in its class, as well as being rated best in class for performance feel and powertrain refinement. Both the naturally aspirated and supercharged versions of the new 4.2-litre V8 are even lighter (6kg and 14kg respectively) than their 4.0-litre predecessors, and with the additional benefit of the new transmission, offer even smoother performance feel. The cylinder block, cylinder heads and many other major components are, as before,in lightweight aluminium alloys. All the weight savings in the new engines are to the benefit of both responsiveness and outright acceleration.
The new-generation 4.2-litre AJ-V8s have excellent economy for engines giving this level of performance, and as with the original engine they are again among the best in class. The naturally-aspirated 300bhp XK8 coupe achieves 34.0mpg (8.3litres/100km)in the EU extra-urban cycle, and has a combined fuel consumption of 24.9mpg (11.3litres/100km). The supercharged 400bhp XKR coupe delivers 31.0mpg (9.1litres/100km)in the extra-urban cycle, with a combined figure of 22.9mpg (12.4litres/100km). Both engines comfortably meet the most stringent current emissions requirement worldwide.
THE NEW 4.2-LITRE AJ-V8 ENGINE:KEY FEATURES
· Capacity increased from 3996cc to 4196cc, with bore and stroke of 86.0/90.3mm (previously 86.0/86.0mm).
· Naturally aspirated XK8 engine produces 300bhp (DIN)and 420Nm (310lb ft)of torque. Supercharged XKR produces 400bhp (DIN)and 553Nm (408lb ft)of torque, with more than 86 per cent of peak torque available from just 2000rev/min. Comparable power and torque figures for the out-going 4.0-litre engine are respectively 290bhp (DIN)/393Nm and 370bhp (DIN)/525Nm.
· Eight cylinders in 90 degree vee, five main bearings, in naturally aspirated and mechanically super charged versions.
· Aluminium-alloy block and cylinder heads for light weight in a compact package with maximum rigidity and strength.
· Redesigned block and bed-plate make new engine even lighter and stiffer than original, further improving refinement.
· Four chain-driven overhead camshafts operating four valves per cylinder with variable inlet and exhaust camshaft phasing.
· Revised camshaft drive further reduces loads and already extremely low levels of radiated noise.
· Valve clearances require no adjustment for life.
· XKR uses belt-driven Eaton rotor-type supercharger with intercooling, now with helical rotor gears for low noise and coated rotors for maximum efficiency – both industry firsts on a production engine.
· Supercharger speed increased, and volumetric efficiency further improved.
· Improvements to fuel-injection system further improves efficiency and reduces emissions.
· Electronic Engine Management System features ‘drive-by-wire’ throttle action with ‘get-you-home’ facility.
SUPERCHARGING:THE KEY TO SERIOUS ACCESSIBLE POWER
Supercharging has been used as a way of extracting more power from the internal combustion engine for almost a century. The power an engine can produce is ultimately limited by the amount of fuel that it can burn in a specific time. And because fuel needs air in which to burn, the amount of fuel that can be burned is limited by the amount of air the engine can take in.
And that’s where supercharging comes in, as one way of increasing the mass of air flowing through the engine. By pumping air into the engine under pressure, rather than having it drawn in by suction alone, more air is delivered. More air means more fuel can be burned and more fuel burned means more power. The detail is far more complicated, but that is the essence of supercharging.
By increasing volumetric efficiency – the volume of fuel-air mixture an engine takes in during one complete cycle, expressed as a percentage compared to the capacity of the engine – supercharging increases power. A 4.2-litre engine taking in 4.2 litres of air-fuel mixture in each cycle would have a volumetric efficiency of 100 per cent – but in practice, with a naturally aspirated engine, that is not possible, because of the effects of friction and pumping losses in the intake system. A supercharged engine, however, forces mixture into the engine and can reach a volumetric efficiency figure of more than 100 per cent,with 130 per cent quite possible.
THE NEW SIX-SPEED TRANSMISSION
The original XK8 introduced Jaguar’s first ever five-speed automatic. Now,the new-generation XK moves the game on once more, becoming the second Jaguar (after the S-TYPE R sports saloon) to adopt ZF’s 6HP26 six-speed automatic transmission.
This is not a Continuously Variable Transmission (CVT) with six intermediate steps, rather it is a traditional automatic transmission with six ratios. With ‘Mechatronic’ shift control providing an adaptive shift strategy that responds both to road conditions and the way the car is being driven, the transmission gives the smoothest possible shifts and optimum performance. This is complemented by changes to the final drive to match the increased power of the new engine,and a revised version of Jaguar's ‘J-Gate ’selector, which has a smoother shift action. The transmission gives improved performance with better economy, is lighter, more compact and mechanically simpler than the five-speed automatic it replaces, and requires minimum maintenance for life.
Through the J-Gate...
The traditional Jaguar J-Gate is retained in the new-generation XK – but with the addition of an extra shift point. A package of design changes – notably improved detents for each gear position – give improved shift feel, while other advances give a smoother but more positive pull away on gradients.
The J-Gate layout is familiar. On the right-hand side of the gate is a traditional PRND (Park, Reverse, Neutral and Drive) pattern. The D position on the right provides fully automatic control of all six gears. By moving the lever to the left-hand side of the gate the driver moves from Drive into fifth gear and can then shift sequentially down the lower gears to second simply by moving the lever to the appropriate position. The transmission will continue to operate automatically as and when it needs up-or downshifts, but will not engage gears higher than the one selected. A ‘sport’ mode switch adjacent to the J-Gate allows the driver to select one of two modes, N being Normal and S being Sport. Selecting Sport mode causes the gear shift points to be raised, making full use of the engine’s power.
The final drive has also been revised for the new-generation XK, and is specifically retuned and mechanically refined to match the increased torque of the new V8s and the change to six speeds instead of five. The overall result,again,is smoother and even more effortless performance.
GEARING UP FOR ACTION :THE TRANSMISSION IN DETAIL The state of the art 6HP26 transmission is built by renowned transmissions giant, ZF. It has six automatic forward speeds and one selectable reverse gear. In technical terms, it is a co-axial planetary transmission with a hydrodynamic torque converter and a slip-controlled lock-up clutch. In simple terms,that means a six-speed automatic with torque converter lock-up in all six forward gears and in reverse. It is controlled by a Bosch ‘Mechatronic’ control module, and operated by a revised version of Jaguar’s trademark ‘J-Gate ’gear selector system. It features filled-for-life lubrication, and has an on-board self-diagnostic facility. Its greater efficiency leads to improved vehicle performance and better fuel economy. Design details that reduce fuel consumption and so emissions, include a high sixth gear and low-viscosity oil.
As well as offering the world ’s first availability of six stepped ratios, the higher torque capacity is easily capable of handling even the XKR ’s massive output with a good deal in reserve. With a die-cast aluminium main casing and GRP composite sump, the transmission weighs only 89kg, a 12 per cent weight saving over the five-speed automatic in the original XK. Mechanically simpler, with an epicyclic gear train making it possible to produce six gears with 30 per cent fewer components than a standard five-speed automatic transmission, it is also more compact externally, with a 50mm reduction in length and 7mm additional ground clearance. This allows a smaller installation space, which improves the overall packaging.
The performance of the transmission is further refined by Bosch’s equally advanced TCM Transmission Control Module. This Mechatronic module (which is neatly integrated into the main transmission housing) combines the hydraulic shift unit and electronic control modules. Its simple cable and plug connections between control module and transmission eliminate more complicated wiring harnesses and connectors, improving reliability. Continuous data provision on transmission and vehicle operating conditions results in drive and shift strategies that ideally match the prevailing conditions, with the adaptive shift strategy taking into account such details as whether the car is operating under heavy load, or being driven with cruise control activated.
CHASSIS AND RUNNING GEAR
Classic design underpinning advanced technologies
Like all modern Jaguars, the new-generation XK features an impressive portfolio of state-of-the-art, driver-focused electronic aids to make driving safer as well as highly enjoyable. Behind the latest innovations in relevant technology, the XK has a pedigree of basic excellence that runs deep. The two-door monocoque shell,which is extremely stiff and very strong – yet still surprisingly lightweight – is quite literally the base on which the XK ’s success has been built. Using high-strength steels in key areas, including the front chassis members, the suspension and bumper mounting points, door intrusion beams and seat-belt anchorages, the body is a triumph of engineering. Direct glazing for the convertible model’s windscreen and the coupe’s front and rear screens adds further torsional rigidity, which in turn adds refinement. The convertible retains additional stiffening to restore the rigidity inevitably lost in removing the fixed roof.
“The XK ’s taut ride and handling,the precise steering and powerful braking performance, and the high levels of comfort and refinement all begin with rigorous Jaguar engineering.”
RUSS VARNEY, CHIEF PROGRAMME ENGINEER
A stiff shell also provides the best foundation for exceptional suspension performance, which has always been a Jaguar hallmark. This delivers a combination of performance, ride comfort, sporty handling and on-road refinement with high levels of driver involvement – the magical mix of characteristics that has always defined the XK8 and is taken to new levels in the latest generation XK family.
Designed for control with comfort
The XK has independent front suspension with double, unequal-length wishbones, coil springs and telescopic dampers. This is a classic layout, but with many Jaguar refinements. The road springs are mounted directly on to the body. The wishbones are secured to an immensely rigid but very light all-aluminium-alloy front crossbeam, which in turn has hydraulic mounts between it and the engine. The former reduces suspension bush loads and permits a taught suspension tune without detrimental body NVH, to the benefit of handling and durability; the latter are tuned so that spring loads remain isolated for superior engine isolation, enhancing both handling and refinement.
The rear suspension also uses coil springs,independent telescopic dampers, and an unequal length wishbone layout with the driveshafts acting as upper links. Like the front suspension the assembly is mounted on an isolated subframe (in this case on rubber bushes), for optimum refinement. The detailed design provides high levels of fore and aft compliance to enhance ride comfort and positive location to eliminate axle tramp even under hard acceleration. Anti-squat geometry prevents the tail dipping under hard acceleration.
XKR now with Brembo brakes as standard
All Jaguar XKs have extremely powerful brakes, with ventilated discs at all four wheels and four-channel ABS anti-lock function as standard. The normally aspirated 300bhp XK8 has radially ventilated disc brakes all round (325x28mm at the front and 305x20mm at the rear), with vacuum assistance. The system gives excellent braking power with low pedal effort while retaining plenty of pedal sensitivity and ‘feel ’. This is especially noticeable with gentle brake applications at low speeds.
The supercharged XKR, with its greater performance, now has Brembo brakes as standard. The system features 355x32mm ventilated front discs and 330x28mm ventilated rear discs, with four-piston aluminium calipers carrying the Jaguar R Performance logo. Steel-braided brake lines complete the highly impressive specification and give the XKR stopping power and feel more than equal to its exceptional performance. The Brembo braking set-up is available as a cost option on XK8, linked to one of the three 20-inch R Performance styles available.
THE LATEST TECHNOLOGY
Electronic driver aids
A car with the power and performance potential of the new-generation Jaguar XK deserves the best in mechanical and electronic driver safety aids – and this car gets them. Features including Dynamic Stability Control (DSC), Emergency Brake Assist (EBA),and Jaguar ’s Computer Active Technology Suspension (CATS) system are all standard (CATS optional on XK8). Also standard on every new-generation XK model is Jaguar’s Adaptive Restraint Technology System (A.R.T.S.), which is universally acknowledged as a major advance in passive vehicle safety.
CATS :COMPUTER ACTIVE TECHNOLOGY SUSPENSION First among these is Jaguar’s Computer Active Technology Suspension system, ATS – further enhanced, and standard on the XKR as well as being available as an option on the XK8. This is an electronic control system which combines uprated springs to increase roll stiffness with adaptive dampers to optimise ride refinement – again delivering the blend of driving dynamics with comfort and refinement that is a Jaguar hallmark. This sophisticated technology allows the XK to be two kinds of car in one package – a true sports car, but with the comfort of a luxury grand tourer. In simple terms, CATS works by continuously adjusting the damping characteristics to suit driving conditions, optimising both ride and handling. A series of sensors provide information to the electronic control unit, which is mapped to deliver the best solution to dampers that can switch between firm and soft settings in milliseconds. When the car is started, damping defaults to the firm setting, but switches to the softer setting once the car is travelling at more than 5mph (8kp/h) on a smooth, straight road. When the XK encounters bumps,or during cornering and braking, the settings switch instantaneously to the firmer mode, reducing roll and increasing stability.
DSC: DYNAMIC STABILITY CONTROL
Dynamic Stability Control is one of the XK’s front-line electronic safety features. It is not a substitute for careful and considered driving,but it does allow performance potential to be responsibly explored, with a powerfully reassuring back-up.
This active system enhances safety at the car’s limits of grip and roadholding, which is especially valuable when road conditions are poor.Unless it is manually switched off (in which case a warning light in the dashboard will remind the driver that they are travelling without DSC)the system operates automatically whenever the engine is running. A warning light also flashes when the system is intervening to restore stability.
A series of sensors detect specific kinds of motion and send information to the Electronic Control Unit (ECU), which in turn activates a hydraulic modulator that interacts with the braking system. The sensors detect the speed of each wheel (and more importantly their relative speeds)for both the ABS and DSC systems; monitor the steering angle at the steering wheel rim (inputs of as little as one-and-a-half degrees or about 5mm of wheel movement can be detected);measure yaw rate, which is the rate of rotation of the vehicle about a vertical axis and indicates that it is understeering at the front or oversteering at the rear; lateral acceleration – the sideways cornering force – and also measure hydraulic brake pressure, to interpret whether or not the brakes are being applied.
Essentially, the system uses the steering wheel angle to interpret the direction in which the driver intends the car to go and compares that with the direction actually taken by the vehicle. If the onset of instability – either understeer or oversteer – is recognised, the system takes measures to restore stability,either by reducing engine torque via the ECU, selectively applying gentle braking to one or more wheels, or both. Working with the drive-by-wire throttle and the ABS system, it will make corrections to enable the car to follow the driver’s steering input. If the driver tries to keep the throttle open the DSC will reduce the power anyway and if the driver does not apply brake pressure, DSC will. The system also intervenes to prevent wheelspin, again by automatically reducing power and if necessary braking individual wheels.
DSC does not discourage a driver from enjoying the full abilities of the XK's highly developed chassis; rather it allows the car to be driven enjoyably, but with a safety net. Controlling wheelspin can actually improve acceleration, especially on surfaces with uneven grip. And because it can be switched off, the wheelspin-controlling element of DSC will not leave the driver stranded in special circumstances, such as when snow chains are fitted, or when trying to drive out of deep,soft snow or sand.
If the system has been switched off and the sensors detect an emergency situation, DSC will automatically re-engage as soon as the brakes are applied. What's more, the DSC system is tuned specifically to match the characteristics of the XK. The manner in which it makes corrections depends on the problem it is correcting. If the car oversteers in a left-hand corner, for example, (with the tail sliding outwards) DSC will apply the right-front brake to provide a corrective effect. If the car understeers in a left-hand corner (with the nose pushing wide) it will apply the left-rear brake to help turn into the corner. If the problems are caused by too much power being applied, DSC will reduce power.
EBA: EMERGENCY BRAKE ASSIST
Research shows that even in emergency situations most drivers do not apply the maximum possible braking pressure. This prevents those drivers from entering the 'ABS zone', the area of maximum braking efficiency immediately prior to the point where the wheels lock and the anti-lock function comes into action. Jaguar's Emergency Brake Assist (EBA)system is designed to overcome this. When EBA detects a rapid application of the brake pedal it interprets it as an emergency braking situation and automatically applies the additional pressure that the driver has not provided, producing maximum braking effort. Not only that, but it does so more quickly than the driver could. This can dramatically cut braking distance, with obvious safety benefits.
CRUISE CONTROL AND ADAPTIVE CRUISE CONTROL
Cruise Control is now standard on the XK, and Adaptive Cruise Control (ACC) is an option across the range. Cruise Control is already a familiar feature, allowing the driver to set a chosen speed, which the car will then maintain with no input from the driver’s feet. Cruise Control maintains constant speed by adjusting the throttle (and if necessary by automatically shifting to a more suitable gear). It is immediately overridden by touching the brakes, or the cancel button, but the previously set speed can be resumed by touching the resume button.
ACC, which Jaguar introduced as an option on the previous XKR, takes the function of cruise control an important step further. ACC detects slower vehicles ahead, or can sense another vehicle crossing into ‘your ’lane. If this happens, speed is adjusted to suit, overriding the set cruise speed to maintain the gap and removing the need for the driver to adjust or cancel the set speed.
ACC uses microwave radar technology to sense slowing traffic and then interacts with the throttle (and if necessary the brakes)to select an appropriate speed. Jaguar’s system, which makes many more individual measurements on each horizontal radar scan than other systems, displays the set speed permanently in the instrument panel. If the sensors are obscured (by mud or snow,perhaps) a ‘Sensor Blocked ’message appears, warning the driver.
A further development of the innovative ACC technology is Forward Alert, which provides an audible warning of slowing traffic ahead, but unlike ACC, does not reduce the throttle or apply the brakes. System sensitivity can be set to a preferred range, which is indicated in a dashboard display.
A.R.T.S.:ADAPTIVE RESTRAINT TECHNOLOGY SYSTEM
Jaguar’s world-leading Adaptive Restraint Technology System (A.R.T.S.) is standard on all XK models and is a major advance in passive safety systems.The previous XK introduced the world’s first ultrasonic occupant sensing system, which employs ultrasonic technology and a seat weight sensor to detect the presence, position and size of a front seat passenger. This information is used to determine airbag energy levels most appropriate to that occupant during a frontal crash. If the front passenger seat is unoccupied, that airbag will not deploy in the event of an accident.
The occupant sensing part of the system works by using ultrasonic signals to determine the position of a front-seat passenger’s head and upper body in relation to the front airbag position. Four ultrasonic sensors are located in the A-and B-pillars and in a modified roof console. If the passenger is too close to the fascia, a warning light will show that the system would restrict deployment of the airbag. When the passenger is far enough away the airbag becomes available again and the light goes out.
“We are committed to world-leading safety and communications technologies that further strengthen the appeal of Jaguar’s highly successful sports coupes and convertibles.”
DR NICK BARTER,DIRECTOR OF PRODUCT DEVELOPMENT
A.R.T.S. communicates through a central processor and uses all its information to control whether the two-stage airbags are deployed at all, or inflated fully or only partially. If the front airbags are deployed, they will be inflated fully or partially depending on the severity of the impact and the data from ultrasonic occupant sensing. In a severe impact the airbags will be deployed with full force. In other circumstances, for example a low-speed collision and with a smaller front-seat occupant in the car, the airbag will not inflate with full force because it does not need to, and because doing so could actually be more hazardous. That means that in every case the XK airbags provide the maximum level of appropriate protection, but not so much ‘protection ’as may be harmful.
Convenience as well as safety
The XK continues to offer heated 12-way electrically adjustable driver and front passenger seats. As standard on both XK8 and XKR, the steering column is electrically adjustable through a wide range of positions, for both reach and rake. The column position is included in the two driver seat-memory settings, and also includes the switchable option of an automatic ‘entry and exit’ mode. Steering wheel multi-function controls incorporate cruise control, audio and telephone controls. In the convertible, the fully trimmed and snug fitting hood, with heated glass rear window, operates at the touch of a single button, from open to closed, or vice versa, in 20 seconds – even when the car is moving, at speeds of up to 10mph.
APPEARANCE AND OPTIONS
Some of the visual changes to the new XK are to bring its badging into line with the rest of the Jaguar range while underlining its position at the top of that range.Uniquely for the XK there are new sculpted Jaguar ‘growler’ badges and a new ‘leaping cat’ emblem on the airbag door and other interior components. There is a prominent new ‘R’ logo on the supercharged models, which carry the ‘Jaguar Supercharged’ badge on their nose. The XKR also has distinctive bonnet louvres, fine-mesh grille, and the ‘R’ logo appears on the XKR gearknob, which also has alloy side inserts in the leather covering.
In the areas where the XK has changed most obviously, it has changed for reasons of improved function and practicality. New headlight details, with black rather than chrome recesses around the powerful Xenon lights, feature on the XKR. The finisher above the XKR rear number plate is now body-coloured.
Three new alloy wheel designs are added to the wide choice already available for each variation of new XK. The R Performance optional wheels are made by performance wheel specialists BBS, and feature two-piece modular construction with die-cast and spun rims and titanium screws, one of which neatly conceals the tyre valve. The full range includes 17-,18-,19-and 20-inch wheels. The new additions are the 17-inch Gemini styles, which becomes standard equipment on the naturally aspirated coupe and convertible, the optional 18-inch Centaur and the 18-inch Hydra, which is new for the XKR. A wide choice of other styles is available, the most extreme option remaining the 20-inch BBS alloy wheel with ultra low profile Pirelli PZero tyres.
As well as being an unmistakable styling signature for the XK, the car’s shapely headlights have more to them than meets the eye. Light sensors detect low ambient light, and in Autolamp mode the sensors automatically turn on the sidelights and low beam headlights when outside light levels drop. On the new XK, turning on the wipers for more than 20 seconds automatically turns on the headlights when in Autolamp mode. The XKR has high-intensity Xenon headlights, the blue-white discharge light providing measurably greater intensity than that of a halogen bulb. The XKR’s lights also feature automatic levelling and power wash as standard, and similar Xenon lights and the power-wash system are available as an option on the XK8. The power-wash feature uses powerful nozzles, integrated into the light units,to blast dirt from the lenses. Inside the XKR headlight shell, the areas surrounding the reflectors are now finished in black rather than chrome. A button on the key fob allows the headlights to be turned on for 25 seconds from outside the car, to aid a driver approaching a parked car in the dark.
NEW COLOURS AND TRIM
Four new exterior colours – Adriatic Blue, Jaguar Racing Green, Ebony and Midnight – replace four of the existing paint colours,and there is a range of new interior trim options.Adriatic Blue is a metallic, rich mid-to-dark blue; Jaguar Racing Green is a distinctive darker metallic green that shows lighter undertones under strong light; Ebony is a pure, solid black; and Midnight is a dark, deep and metallic black.
The new interior trim options,with beautifully stitched full leather seat facings, include both single colour and contrast options, from a sophisticated pallete. The choice now includes full ranberry or Heritage Tan upholstery, or Ivory and Warm Charcoal. Dove is added to the traditional Cashmere, and there is a choice of five multi-layer canvas hood colours – Black, Blue, Green and Light and Dark Beiges. A choice of hand-finished wood veneers includes traditional burr walnut or sporty, grey-stained birds-eye maple, while steering wheel options include colour-keyed wood-and-leather, or all leather from the R Performance options range. All XKs, not only the XKR, now include the performance option of specially shaped Recaro sports seats trimmed in soft grain leather and available in three colours, and the Aluminium Pack. This comprises alloy instrument bezels, J-Gate surround,door release levers, pedal pads and tread plates. New domed finishers on the centres of each dashboard needle give a sense of even deeper quality in the classic analogue dials.
New for the 2003 model year XK is the option of a built-in compass display for the self-dimming electrochromatic interior mirror, while the body-coloured exterior mirrors are power-adjustable and heated. The latest DVD-based satellite navigation options include new navigation discs for an extended range of European countries, including Spain and Portugal and Sweden and Denmark, and also adds Canada to the USA disc. The start-up display includes an analogue-style clock, very much in keeping with Jaguar style.
“The XK is a car for individuals. From a superb starting point of one of the finest luxury sports cars in the world, you can create the car that you want.”
LAWRENCE THOMAS, XK BRAND MANAGER
The XK looks after driver and passengers. Audio choices begin with the Premium Sound Alpine system, with 320 watts of audio power, nine speakers (eight in the convertible) and a six-disc CD autochanger, boot-mounted for security. It also offers the option of a dual-band telephone, mounted in the centre armrest and with its own touchpad or steering wheel controls. Also for security, all XKs have as standard drive-away door and boot locking, and a ‘valet-key’ locking system to isolate boot and interior storage.
R PERFORMANCE OPTIONS
For the sportiest XKs of all – or the sportiest XK drivers – the R Performance range offers a series of options for all models. These include not only the ‘Aluminium Pack’, comprising instrument bezels, J-Gate surround, door release levers, pedal pads and tread plates, but also all-leather steering wheel rims and gearshift knobs, and a choice of BBS wheels. The R Performance Handling Pack (coupe only) provides a revised, sportier set-up for the CATS Computer Active Suspension System (with uprated springs and anti-roll bars, a lower ride height and retuned steering assistance) plus 20-inch wheels with ultra-low profile tyres, backed by the top specification Brembo brakes.
XK8 or XKR, coupe or convertible, the latest generation of the XK offers everything it ever did – and now even more.
THE NEW-GENERATION JAGUAR XK:PRICE LIST
ON THE ROAD PRICE
JAGUAR XK8 COUPE £48,700.00
All prices are based on manufacturer’s recommended prices. List Prices apply throughout Great Britain, Northern Ireland, the Channel Islands and the Isle of Man. “On the road prices” are included for the benefit of purchasers in Great Britain and Northern Ireland only and are calculated using Retail Prices from this price list and adding 12 months Vehicle Excise Duty, delivery to the Jaguar Dealer premises, first registration fee and an estimated price for number plates and a full tank of fuel. All Jaguar vehicles first registered after 01 March 2001 will attract Vehicle Excise Duty at £155 per annum (Band D Petrol).
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