Jaguar XF Wheels and Tyres
Depending on market and model, the XF is available with 17, 18, 19 or 20-inch wheels; the SV8 being the only car in its class to have 20-inch wheels as standard. All are cast in aluminium alloy and every design combines maximum strength with minimum weight. To satisfy Thatcham security stipulations, there are also 20 variations of anti-theft locking nut. All cars for the majority of markets carry the same specification of 18-inch diameter alloy mini-spare.
For major European markets, cars with 17 and 18-inch wheels are fitted with the Jaguar Tyre Repair System as a space and weight-saving alternative to the ‘mini-spare’. This replaces the spare wheel, jack and tool kit, and can effect a temporary repair of any puncture of up to 6mm diameter in the tread area - sealing the hole and re-inflating the tyre to enable the car to be driven to where a permanent repair or replacement can be carried out. When fitted in lieu of a spare wheel, the Jaguar Tyre Repair System liberates an additional 40 litres of stowage space under the boot floor.
Jaguar XF Driver Aids
The XF’s main control module governs many key safety functions including Emergency Brake Assist (EBA), Electronic Brakeforce Distribution (EBD), Anti-lock Braking System (ABS), Traction Control through engine and brake intervention, Dynamic Stability Control (DSC), Cornering Brake Control (CBC) and Engine Drag Torque Control. And for the first time, the XF adds Understeer Control Logic, which has been designed to mitigate understeer by intervening through the engine management and braking systems to decelerate the car and help restore grip to the front wheels.
A two-stage DSC system similar to that featured on the new XK is standard. It combines the normal on-off switchable DSC function, which reacts as soon as it detects slip, with Trac DSC, which allows more slip before intervening – better for a more sporting driving experience. It also allows a degree of wheel overspin on deep soft surfaces, which is essential for running with snow chains. The system defaults to normal ‘DSC on’ with each ignition-on sequence.
In Dynamic Mode (SV8 only), pressing and holding the DSC button fully disables the system, allowing an experienced driver to exploit fully the capability of the chassis, where conditions allow. Mode selection is confirmed on the instrument cluster display.
Also new on XFs fitted with Adaptive Cruise Control (ACC) is Electronic Brake Prefill. This senses any rapid throttle lift-off and initiates a small brake hydraulic pressure build-up in anticipation of the brakes being applied, to give better pedal response and slightly shorter stopping distances.
JaguarDrive ControlTM offers different modes that interact with the DSC system, engine and gearbox, to change the characteristics of engine mapping, transmission shifts and brake interventions depending on driving conditions and circumstances. On naturally aspirated cars JaguarDrive ControlTM has Normal and Winter modes, on the SV8 model there are Normal, Winter and Dynamic modes - the last of these to allow a more purposeful driving style.
Jaguar XF Powertrain
The new XF will be available with a choice of four engines - 2.7-litre V6 turbodiesel, 3.0-litre V6 petrol, 4.2-litre naturally aspirated V8 petrol, and 4.2-litre supercharged V8 petrol (depending on market). All will have that classic blend of power and refinement that makes Jaguar stand out from its rivals, says Mick Mohan, XF Chief Programme Engineer:
“The XF’s engines combine effortless performance, unrivalled character and an impeccable pedigree. The six-speed automatic transmission is the best Jaguar has ever had. The Jaguar Sequential ShiftTM manual gearchange adds a whole new level of functionality. This combination – already proven in the XK – produces excellent powertrains for a very sporting Jaguar.”
Both petrol and diesel V6 engines are offered in Luxury and Premium Luxury models; the naturally aspirated V8 will be Premium Luxury only (and Luxury for US models) and the supercharged SV8 has its own unique specification, for a very logical, easily understood range with only six major variants.
The Euro IV compliant twin-turbocharged 2.7-litre 24-valve V6 diesel delivers high efficiency, high performance and class-leading refinement – its headline figures including 207PS (EEC) and 435Nm (EEC) of torque. With its Compacted Graphite Iron (CGI) cylinder block and aluminium cylinder heads it is the lightest diesel engine of its type and size - making a significant contribution to the new XF’s power-to-weight ratio, performance and fuel economy.
The V6 diesel features the latest generation high-pressure Common Rail direct-injection, ‘multiple pilot’ injection, and piezo-electric injection control, allowing sophisticated management of the injection patterns to make combustion smoother and quieter. Four valves per cylinder and advanced combustion chamber shapes contribute to high combustion efficiency with low combustion noise, alongside very low mechanical noise levels.
Emissions are further reduced by using twin variable-geometry turbochargers with electronic control, exhaust gas recirculation, and a variable-swirl intake system. Using two small turbochargers, with ‘drive-by-wire’ throttle control, rather than one larger unit, also gives a quicker, smoother response.
The 3.0-litre V6 petrol engine is another compact, lightweight, all-aluminium design with four overhead camshafts, four valves per cylinder, VCP Continuously Variable Cam Phasing and variable geometry air intakes. It produces 240bhp (SAE)/238PS (EEC) and 221lb ft (SAE)/293Nm (EEC) peak torque - with more than 80 per cent of peak torque from below 1500rpm to maximum engine speed at 6800rpm.
Variable Camshaft Phasing produces faster response and performance at all engine speeds - with more torque at low speeds and maximum power at high speeds. It also provides internal exhaust gas recirculation, reducing both hydrocarbon and NOx emissions.
The 4.2-litre V8 comes in naturally aspirated or supercharged versions. With a ribbed aluminium block and cylinder heads it is very light but extremely strong, and its superb structural stiffness minimises radiated engine noise and increases mechanical reliability. The V8’s exhaust system has also been completely retuned to remain quiet at cruising speeds but deliver a substantially more purposeful V8 roar under hard acceleration.
In naturally aspirated form it develops 300bhp (SAE)/298PS (EEC), and 310lb ft (SAE)/411Nm (EEC) of torque. The supercharged version uses a highly efficient rotor-type supercharger, belt-driven from the crankshaft. It develops 420bhp (SAE)/416PS (EEC), and 408lb ft (SAE)/560Nm (EEC) of torque from low engine speeds. Just as important as the supercharged engine’s peak torque is the way the usable torque is spread across a wide rev range - with at least 86 per cent of the peak from 2000rpm to maximum engine speed.
A superior six-speed automatic transmission – renowned as one of the best in the world and already proven in other Jaguars - is used on all versions of the new XF. There is no manual gearbox option. The transmission is a key element in the XF's sporting character, its adaptive gear-changing strategies responding both to road conditions and the way the car is being driven, giving the smoothest shifts and optimum performance. Adding another layer of driver focus, the transmission is controlled by the new JaguarDrive SelectorTM with the option of manual selection through Jaguar Sequential ShiftTM. The JaguarDrive SelectorTM is also used to access the XF’s Sport mode which uses shift-by-wire technology pioneered on the XK.
These high-tech, modern powertrains give every XF model outstanding performance. The 2.7-litre V6 diesel reaches 60mph in just 7.7 seconds (0-100kph in 8.2 seconds) and has a top speed of 143mph (229kph). The 3.0-litre V6 petrol version sprints to 60mph in 7.9 seconds (0-100kph in 8.3 seconds) and goes on to reach 148mph (237kph). The naturally-aspirated V8 model has a superb 0-60mph time of just 6.2 seconds (0-100kph in 6.5 seconds) and has an electronically limited top speed of 155mph (250kph). Lastly, the supercharged SV8 XF storms to 60mph in just 5.1 seconds (0-100kph in 5.4 seconds) and, like the naturally aspirated V8, is limited to a maximum of 155mph (250kph).Published 28 August 2007