Jaguar XFR, 2010
The enhanced exterior styling of the Jaguar XFR moves those sporting credentials on even further, to deliver the ultimate expression of Jaguar's new saloon car design language - carrying a number of visual design cues that are intrinsic to Jaguar's 'R' car philosophy. Its unique front-end design has a larger lower grille with new black-finished mesh, plus chrome outboard air intakes. The upper mesh grille retains XF's bright finish, while the bonnet carries distinctive louvres, like those on the XKR sports car.
The Jaguar XFR also features bold new sill extensions, while the rear bumper adds a unique body-coloured lower valance panel incorporating the 'R' signature of four large, bright-finished tail pipes. The new bootlid spoiler has a significant aerodynamic effect. Developed in conjunction with the new front bumper design, it further improves the Jaguar XFR's front/rear lift balance, and therefore its high-speed stability. A new exterior mirror design also offers aerodynamic improvements, plus improved functionality with its LED side repeaters.
The Jaguar XFR's sporting character is clearly apparent in the 20-inch Nevis alloy wheels. It is the only car in its class to offer this size of wheel as standard specification. Those twin-seven-spoke wheels bear the wording 'Jaguar Supercharged' embossed around their centres, and are wrapped tightly around silver-grey brake callipers, which carry the evocative 'R' logo. The R badge also appears on the right-hand side of the boot lid drop panel, to complete the XFR's external visual identity.
The new Jaguar XFR is offered with a select palette of just eight exterior colours: Ultimate Black, Indigo, Liquid Silver, Lunar Grey, Porcelain, Botanical Green, Kyanite Blue and Salsa. All except Salsa and Porcelain are metallic colours and, within the XF range, Salsa and Kyanite Blue are unique to Jaguar XFR. For each colour - as across the entire XF range - Jaguar suggests a 'Designer's Choice' of the leather trim colours that best complement each body colour and the Warm Charcoal upper facia that is standard on every Jaguar XFR.
The interior design theme is modern and individual. The cabin environment is uniquely Jaguar and in the XFR more details hint at the car's performance. A full soft grain leather interior is standard, with four colour choices - Warm Charcoal, Warm Charcoal/Red Zone, Warm Charcoal/London Tan, and Ivory. A new Dark Oak veneer is the standard finish for the Jaguar XFR's wood-trimmed areas. New 18x14-way adjustable sports seats have electrically adjustable squab bolsters for significantly improved support at higher cornering speeds. Each Jaguar XFR seat has the 'R' logo embossed on its squab and the front seats have leather seat-back map pockets.
The fascia introduces a unique, dark mesh aluminium finish, and another discreet 'R' badge on the passenger side of the instrument panel. The speedometer and tachometer have the unique sporting signature of red dial pointers, and carry the 'Supercharged' motif. And at start-up, the 'R' logo appears on the Touch-screen as part of the XFR 'driver handshake' sequence.
The most advanced Jaguar V8 engines ever
The supercharged 5.0-litre V8 that powers the new XFR is Jaguar's new flagship engine, but it is only half of the petrol engine story - a naturally-aspirated version of the all-new engine brings additional advanced technologies and performance to other models in the XF range.
Light, robust and very strong
The all-new 5.0-litre V8 petrol engines are built around a stiff, all-new, aluminium block with cast-in iron liners and cross-bolted main bearing caps to reduce noise, vibration and harshness. For the first time at Jaguar the blocks are high-pressure die-cast, providing a superior finish and greater dimensional accuracy. The engines use aluminium heads, with four valves per cylinder and strong, spheroidal-graphite cast-iron crankshafts and forged steel connecting rods. The cylinder heads for the first time are specified with a secondary (recycled) aluminium alloy, reducing the environmental impact of manufacturing the new engine.
The new 5.0-litre V8 engines are more compact than their predecessors. Overall engine length has been reduced by 24mm by relocation of the oil pump within the engine architecture. This length reduction improves engine bay packaging in support of enhanced safety cell performance while ensuring overall engine weight is virtually unchanged.
Direct injection - power with economy
One of the key features of the new petrol engines is an industry-first, centrally-mounted, multi-hole, spray-guided fuel injection system, delivering fuel at a pressure of up to 150bar directly to the cylinder. This substantially contributes to improved low-speed, dynamic response. The positioning of the injectors ensures fuel is precisely delivered to the centre of the combustion chamber, maximising air-fuel mixing, and improving combustion control. Fuel is delivered via twin, high-pressure fuel pumps that are driven via an auxiliary shaft in the all-new engine block.
The charge-cooling effects of the direct-injection fuel system have allowed the compression ratio of the naturally aspirated engine to be raised to 11.5:1, further improving the engine economy. The supercharged engine also benefits from an increase from 9.1:1 on the previous 4.2-litre version to 9.5:1.
During the engine warm-up phase, the combustion system employs multiple injection mode strategies to deliver 50 percent more heat for fast catalyst warm-up and substantially reduced emissions.
Torque-actuated Variable Camshaft Timing improves efficiency
A new type of variable camshaft timing system (VCT) introduces another new technology. The four VCT units are activated by the positive and negative torques generated by opening and closing the intake and exhaust valves, instead of by oil pressure. This has allowed the engine oil pump to be reduced in size, saving energy and reducing fuel consumption.
VCT units work independently on all four camshafts with 62 degrees of authority on the inlet cams and 50 degrees of authority on the exhaust cams. Timing is optimised by the engine control unit for torque, power and economy at every point in the engine's speed range.
The response rate of the new VCT units is up to three times faster than before, with actuation rates in excess of 150 degrees per second. This delivers a more immediate engine response to the driver's demand.
The naturally aspirated engine is also equipped with camshaft profile switching (CPS) on the inlet camshaft. Depending on the engine's running conditions and the demands of the driver, the CPS will switch between a profile that is ideal for low-speed driving, and another which gives increased valve lift for high performance.
Variable Inlet Manifold optimises torque through the rev range
A new variable inlet manifold (VIM) can vary the length of its eight inlet tracts to optimise power and torque throughout the rev range on the naturally aspirated engine. Vacuum-operated actuators open valves to select a longer, 680mm inlet tract at low revs, increasing the rate of both the airflow and the engine torque. As the revs climb beyond 4700rpm, the actuators select a shorter, 350mm path allowing a greater volume of air into the engine to optimise engine power. The actuator position is optimised by the engine control unit for improved torque throughout the engine speed range.
Improved efficiency through new technology
Minimising internal friction is key to improving fuel consumption and CO2 emissions, and as such was a key aim when it came to the design of the engines. As a result, the new Jaguar AJ-V8 Gen III engines achieve another best in class, setting a new industry benchmark for cranktrain efficiency.
All engine bearings were the subject of an extensive optimisation programme, reducing friction without compromising reliability. Diamond-Like Carbon Coating (DLC) has been used to reduce friction on the fuel pump tappets and a solid film lubricant has been used to coat the piston skirts.
Jaguar has developed a unique, intelligent oil-pump pressure relief valve (PRV) which senses oil pressure deep in the engine's oil galleries to control the oil pump delivery. As a result, oil pump frictional losses are reduced during the warm-up period. New engine oil has a lower viscosity, contributing to an extension in service intervals from 10,000 miles to 15,000 miles or 12 months. Both V8 engines are now fitted with an electronic oil level sensor feature for added peace of mind.
Unique, Jaguar sound quality
Sound quality is a key characteristic of all Jaguars and is one particular aspect that customers relish. With that in mind, Jaguar engineers have deliberately accentuated the acoustic feedback into the cabin in order to further increase driving pleasure.
The Jaguar XFR has received special attention to deliver the required V8 intake sound character commonly absent on supercharged engines. Intake manifold pressure pulsations are fed into an acoustic filter at the rear of the engine that is tuned to "tenor C", with the output from the filter ducted into the cabin. The filter is controlled by the engine management system which allows the acoustics to enter the cabin only under certain conditions, such as when the engine is accelerating hard, thus maintaining the desired sound quality at all times.
New supercharger optimises power
A sixth-generation, twin vortex system (TVS) supercharger is fitted to the Jaguar XFR's 510PS engine. It is a compact Roots-type unit, feeding air through twin intercoolers, which in turn are water-cooled by their own discreet cooling circuit. The high helix rotor design improves the supercharger thermodynamic efficiency by 16 percent. It also improves noise quality to the point where the unit is now virtually inaudible (making supercharger whine a thing of the past). The intercoolers reduce the temperature of the pressurised intake-air and so optimise power and efficiency.
The new air intake has been radically redesigned compared to the previous V8. The intake air path is a direct feed to the supercharger inlet from the centrally mounted front throttle body. Air is delivered through twin air boxes, which reduce flow loss and further increase efficiency.
Mechanically, the new supercharger and its intercoolers are efficiently packaged in the 'V' of the engine to deliver a low overall engine height in support of pedestrian safety requirements.
Advanced six-speed transmissions
The all-new 5.0-litre AJ-V8 Gen III and the 3.0-litre diesel AJ-V6 D Gen III engines transmit power through an enhanced version of Jaguar's acclaimed ZF 6HP28 electronically controlled, six-speed transmission. Additional clutch plates and an uprated torque converter have been added for the supercharged V8 to facilitate the extra power.
The transmission has a fully-adaptive shift system which delivers extremely smooth gear changes and optimises performance and economy at all times. The Jaguar Sequential Shift™ suffers no torque interrupt resulting in a smoother more powerful shift feel and an almost instantaneous shift from the time the driver touches the shift paddle to the completion of the shift event. It also continually adapts to suit driving style, which can vary from sporting to more economical. The 'mechatronic' control module incorporated inside the transmission includes the software for the semi-automatic Jaguar Sequential Shift™ function, selected when the driver operates either of the two steering-wheel paddles.
The high levels of torque produced by the new engines make it possible for the torque converter lock-up feature of the transmission to be used even at low speeds, without slip. This approach provides competitive fuel consumption, contributing to the official combined fuel economy of 22.5mpg (12.5l/100km) in the Jaguar XFR and 25.4mpg (11.1l/100km) in the naturally aspirated V8-powered XF. The advanced design of the transmission includes a torsional damper to absorb firing impulses from the engine, further smoothing the driveline. The transmission is designed to be maintenance-free and the fluid is 'filled-for-life.'
Driving Dynamics
The headline advances made by Jaguar's new engines are hugely significant and impressive. They take Jaguar's philosophy of 'intelligent power' to another new level and that means instant responses, seamless power and smooth, refined performance with comparable fuel economy and better emissions - all thanks to intelligent use of the most advanced technologies. And, of course, in Jaguar XFR guise, it makes for the quickest XF yet.
Jaguar's Emergency Brake Assist is standard on XF and Adaptive Cruise Control (ACC) is now available as an option all models. Advanced Emergency Brake Assist is a new attribute of the ACC system on the new 3.0 V6 diesel and 5.0 V8 petrol models; it uses the ACC radar to calculate distance from and speed of approach to the vehicle ahead and pre-charges the brake-line pressure to minimise impact speed if a collision is predicted - as well as giving an audible warning to the driver.
To improve handling and steering responses, the Jaguar XFR is fitted with a 'fast ratio' steering rack, and additionally benefits from the further improved front-to-rear aerodynamic balance offered by a new boot lid spoiler and deeper front bumper. This is a significant gain as XF's lift balance was already best in class, and its low overall aerodynamic drag coefficient of only 0.29Cd contributes to both low wind noise and inherent high-speed stability.
The XF's body shell is already extremely stiff - in fact the stiffest in its class. This is key to the XF delivering superb ride and handling based on taut body control and precise, responsive steering. The bodyshell for the new MY 2010 Jaguar XF is even stiffer, thanks to a new rear subframe and the adoption of a boot cross-brace that was previously only fitted to the XF SV8 supercharged model.
Latest computer-controlled suspension and differential
The biggest changes in chassis dynamics for the Jaguar XFR, however, come from two new advanced technologies, Adaptive Dynamics and Active Differential Control, which are both incorporated as standard.
Active Differential Control (ADC) with traction-only functionality and handling functionality is an electronically controlled alternative to the traditional, wholly mechanical differential, offering more subtle control strategies.
ADC can vary its locking torque (and therefore the proportion of torque to each driven rear wheel) depending on surface conditions and power applied. Its control strategies optimise traction at each wheel, improving acceleration on low-grip surfaces while also enhancing cornering ability.
ADC has no adverse effect on either refinement or stability - where the traditional, mechanical differential can compromise stability under hard applications of power, demanding more corrective input from the driver. Whereas a mechanical differential is a permanently active part of the drivetrain, the Jaguar XFR's new ADC system is switched off when not required, so does not create undesirable understeer and creates no issues with NVH at lower speeds.
The differential is operated by an internal electric motor and 'ball-and-ramp' mechanism, and contains a multiplate clutch, which transmits or 'vectors' torque to the wheel with most grip. The multi-plate clutch assembly is designed to prevent excessive differential slip, but differs fundamentally from a conventional traction control which uses the brakes to counteract slip after it has occurred.
Continuously variable damping
Adaptive Dynamics, which replaces Jaguar's proven Computer Active Technology Suspension (CATS) on the Jaguar XFR, is a highly sophisticated active damping system which automatically adjusts suspension damper settings to suit both road conditions and the way in which the car is being driven. By removing the need for compromise between a fixed, softer setting for ride comfort and a fixed, firmer setting for tauter body control and handling, Adaptive Dynamics allows the balance between ride and handling to be optimised whatever the circumstances. Unlike earlier systems with only a small number of steps in the damper settings, it offers a progressively variable damping strategy between wide extremes, to deliver a comfortable but sporty ride with impressively sharp handling.
The three primary functions of Adaptive Dynamics are to control vertical movement, roll rate and pitch rate of the body. It does this by analysing induced body motions one hundred times a second, and setting each damper to an appropriate level in order to maintain a constant and level body attitude, thereby optimising control without compromising ride. Also one hundred times a second, it predicts the roll-rate due to steering inputs, and selectively increases damping forces to reduce that roll-rate - improving feel and driver confidence - as well as analysing fore and aft pitch rate due to throttle and braking inputs, and again varies damping forces to reduce pitch, further improving comfort and control.
Jaguar XFR also features Handling Functionality, which is unique in this class. In conjunction with the DSC Off option and JaguarDrive Control™ with Dynamic Mode, this supplements all the advantages of Traction Only Functionality with a number of more driver-focused dynamic characteristics. When selected, Dynamic Mode (which is also standard on the new naturally aspirated 5.0-litre V8 petrol and new 3.0-litre V6 diesel models) modifies the throttle, stability and transmission parameters, and on Jaguar XFR only it also modifies the Adaptive Dynamics responses. The combination of ADC and Dynamic mode with DSC Off allows controllable power-on oversteer, and improves off-throttle stability, allowing quicker, more spirited cornering. It can also improve stability in situations such as an emergency lane-change manoeuvre at high speed and, in combination with DSC, reduce the brake interventions which the more enthusiastic driver might see as intrusive.
The Jaguar XFR also features bold new sill extensions, while the rear bumper adds a unique body-coloured lower valance panel incorporating the 'R' signature of four large, bright-finished tail pipes. The new bootlid spoiler has a significant aerodynamic effect. Developed in conjunction with the new front bumper design, it further improves the Jaguar XFR's front/rear lift balance, and therefore its high-speed stability. A new exterior mirror design also offers aerodynamic improvements, plus improved functionality with its LED side repeaters.
The Jaguar XFR's sporting character is clearly apparent in the 20-inch Nevis alloy wheels. It is the only car in its class to offer this size of wheel as standard specification. Those twin-seven-spoke wheels bear the wording 'Jaguar Supercharged' embossed around their centres, and are wrapped tightly around silver-grey brake callipers, which carry the evocative 'R' logo. The R badge also appears on the right-hand side of the boot lid drop panel, to complete the XFR's external visual identity.
The new Jaguar XFR is offered with a select palette of just eight exterior colours: Ultimate Black, Indigo, Liquid Silver, Lunar Grey, Porcelain, Botanical Green, Kyanite Blue and Salsa. All except Salsa and Porcelain are metallic colours and, within the XF range, Salsa and Kyanite Blue are unique to Jaguar XFR. For each colour - as across the entire XF range - Jaguar suggests a 'Designer's Choice' of the leather trim colours that best complement each body colour and the Warm Charcoal upper facia that is standard on every Jaguar XFR.
The interior design theme is modern and individual. The cabin environment is uniquely Jaguar and in the XFR more details hint at the car's performance. A full soft grain leather interior is standard, with four colour choices - Warm Charcoal, Warm Charcoal/Red Zone, Warm Charcoal/London Tan, and Ivory. A new Dark Oak veneer is the standard finish for the Jaguar XFR's wood-trimmed areas. New 18x14-way adjustable sports seats have electrically adjustable squab bolsters for significantly improved support at higher cornering speeds. Each Jaguar XFR seat has the 'R' logo embossed on its squab and the front seats have leather seat-back map pockets.
The fascia introduces a unique, dark mesh aluminium finish, and another discreet 'R' badge on the passenger side of the instrument panel. The speedometer and tachometer have the unique sporting signature of red dial pointers, and carry the 'Supercharged' motif. And at start-up, the 'R' logo appears on the Touch-screen as part of the XFR 'driver handshake' sequence.
The most advanced Jaguar V8 engines ever
The supercharged 5.0-litre V8 that powers the new XFR is Jaguar's new flagship engine, but it is only half of the petrol engine story - a naturally-aspirated version of the all-new engine brings additional advanced technologies and performance to other models in the XF range.
Light, robust and very strong
The all-new 5.0-litre V8 petrol engines are built around a stiff, all-new, aluminium block with cast-in iron liners and cross-bolted main bearing caps to reduce noise, vibration and harshness. For the first time at Jaguar the blocks are high-pressure die-cast, providing a superior finish and greater dimensional accuracy. The engines use aluminium heads, with four valves per cylinder and strong, spheroidal-graphite cast-iron crankshafts and forged steel connecting rods. The cylinder heads for the first time are specified with a secondary (recycled) aluminium alloy, reducing the environmental impact of manufacturing the new engine.
The new 5.0-litre V8 engines are more compact than their predecessors. Overall engine length has been reduced by 24mm by relocation of the oil pump within the engine architecture. This length reduction improves engine bay packaging in support of enhanced safety cell performance while ensuring overall engine weight is virtually unchanged.
Direct injection - power with economy
One of the key features of the new petrol engines is an industry-first, centrally-mounted, multi-hole, spray-guided fuel injection system, delivering fuel at a pressure of up to 150bar directly to the cylinder. This substantially contributes to improved low-speed, dynamic response. The positioning of the injectors ensures fuel is precisely delivered to the centre of the combustion chamber, maximising air-fuel mixing, and improving combustion control. Fuel is delivered via twin, high-pressure fuel pumps that are driven via an auxiliary shaft in the all-new engine block.
The charge-cooling effects of the direct-injection fuel system have allowed the compression ratio of the naturally aspirated engine to be raised to 11.5:1, further improving the engine economy. The supercharged engine also benefits from an increase from 9.1:1 on the previous 4.2-litre version to 9.5:1.
During the engine warm-up phase, the combustion system employs multiple injection mode strategies to deliver 50 percent more heat for fast catalyst warm-up and substantially reduced emissions.
Torque-actuated Variable Camshaft Timing improves efficiency
A new type of variable camshaft timing system (VCT) introduces another new technology. The four VCT units are activated by the positive and negative torques generated by opening and closing the intake and exhaust valves, instead of by oil pressure. This has allowed the engine oil pump to be reduced in size, saving energy and reducing fuel consumption.
VCT units work independently on all four camshafts with 62 degrees of authority on the inlet cams and 50 degrees of authority on the exhaust cams. Timing is optimised by the engine control unit for torque, power and economy at every point in the engine's speed range.
The response rate of the new VCT units is up to three times faster than before, with actuation rates in excess of 150 degrees per second. This delivers a more immediate engine response to the driver's demand.
The naturally aspirated engine is also equipped with camshaft profile switching (CPS) on the inlet camshaft. Depending on the engine's running conditions and the demands of the driver, the CPS will switch between a profile that is ideal for low-speed driving, and another which gives increased valve lift for high performance.
Variable Inlet Manifold optimises torque through the rev range
A new variable inlet manifold (VIM) can vary the length of its eight inlet tracts to optimise power and torque throughout the rev range on the naturally aspirated engine. Vacuum-operated actuators open valves to select a longer, 680mm inlet tract at low revs, increasing the rate of both the airflow and the engine torque. As the revs climb beyond 4700rpm, the actuators select a shorter, 350mm path allowing a greater volume of air into the engine to optimise engine power. The actuator position is optimised by the engine control unit for improved torque throughout the engine speed range.
Improved efficiency through new technology
Minimising internal friction is key to improving fuel consumption and CO2 emissions, and as such was a key aim when it came to the design of the engines. As a result, the new Jaguar AJ-V8 Gen III engines achieve another best in class, setting a new industry benchmark for cranktrain efficiency.
All engine bearings were the subject of an extensive optimisation programme, reducing friction without compromising reliability. Diamond-Like Carbon Coating (DLC) has been used to reduce friction on the fuel pump tappets and a solid film lubricant has been used to coat the piston skirts.
Jaguar has developed a unique, intelligent oil-pump pressure relief valve (PRV) which senses oil pressure deep in the engine's oil galleries to control the oil pump delivery. As a result, oil pump frictional losses are reduced during the warm-up period. New engine oil has a lower viscosity, contributing to an extension in service intervals from 10,000 miles to 15,000 miles or 12 months. Both V8 engines are now fitted with an electronic oil level sensor feature for added peace of mind.
Unique, Jaguar sound quality
Sound quality is a key characteristic of all Jaguars and is one particular aspect that customers relish. With that in mind, Jaguar engineers have deliberately accentuated the acoustic feedback into the cabin in order to further increase driving pleasure.
The Jaguar XFR has received special attention to deliver the required V8 intake sound character commonly absent on supercharged engines. Intake manifold pressure pulsations are fed into an acoustic filter at the rear of the engine that is tuned to "tenor C", with the output from the filter ducted into the cabin. The filter is controlled by the engine management system which allows the acoustics to enter the cabin only under certain conditions, such as when the engine is accelerating hard, thus maintaining the desired sound quality at all times.
New supercharger optimises power
A sixth-generation, twin vortex system (TVS) supercharger is fitted to the Jaguar XFR's 510PS engine. It is a compact Roots-type unit, feeding air through twin intercoolers, which in turn are water-cooled by their own discreet cooling circuit. The high helix rotor design improves the supercharger thermodynamic efficiency by 16 percent. It also improves noise quality to the point where the unit is now virtually inaudible (making supercharger whine a thing of the past). The intercoolers reduce the temperature of the pressurised intake-air and so optimise power and efficiency.
The new air intake has been radically redesigned compared to the previous V8. The intake air path is a direct feed to the supercharger inlet from the centrally mounted front throttle body. Air is delivered through twin air boxes, which reduce flow loss and further increase efficiency.
Mechanically, the new supercharger and its intercoolers are efficiently packaged in the 'V' of the engine to deliver a low overall engine height in support of pedestrian safety requirements.
Advanced six-speed transmissions
The all-new 5.0-litre AJ-V8 Gen III and the 3.0-litre diesel AJ-V6 D Gen III engines transmit power through an enhanced version of Jaguar's acclaimed ZF 6HP28 electronically controlled, six-speed transmission. Additional clutch plates and an uprated torque converter have been added for the supercharged V8 to facilitate the extra power.
The transmission has a fully-adaptive shift system which delivers extremely smooth gear changes and optimises performance and economy at all times. The Jaguar Sequential Shift™ suffers no torque interrupt resulting in a smoother more powerful shift feel and an almost instantaneous shift from the time the driver touches the shift paddle to the completion of the shift event. It also continually adapts to suit driving style, which can vary from sporting to more economical. The 'mechatronic' control module incorporated inside the transmission includes the software for the semi-automatic Jaguar Sequential Shift™ function, selected when the driver operates either of the two steering-wheel paddles.
The high levels of torque produced by the new engines make it possible for the torque converter lock-up feature of the transmission to be used even at low speeds, without slip. This approach provides competitive fuel consumption, contributing to the official combined fuel economy of 22.5mpg (12.5l/100km) in the Jaguar XFR and 25.4mpg (11.1l/100km) in the naturally aspirated V8-powered XF. The advanced design of the transmission includes a torsional damper to absorb firing impulses from the engine, further smoothing the driveline. The transmission is designed to be maintenance-free and the fluid is 'filled-for-life.'
Driving Dynamics
The headline advances made by Jaguar's new engines are hugely significant and impressive. They take Jaguar's philosophy of 'intelligent power' to another new level and that means instant responses, seamless power and smooth, refined performance with comparable fuel economy and better emissions - all thanks to intelligent use of the most advanced technologies. And, of course, in Jaguar XFR guise, it makes for the quickest XF yet.
Jaguar's Emergency Brake Assist is standard on XF and Adaptive Cruise Control (ACC) is now available as an option all models. Advanced Emergency Brake Assist is a new attribute of the ACC system on the new 3.0 V6 diesel and 5.0 V8 petrol models; it uses the ACC radar to calculate distance from and speed of approach to the vehicle ahead and pre-charges the brake-line pressure to minimise impact speed if a collision is predicted - as well as giving an audible warning to the driver.
To improve handling and steering responses, the Jaguar XFR is fitted with a 'fast ratio' steering rack, and additionally benefits from the further improved front-to-rear aerodynamic balance offered by a new boot lid spoiler and deeper front bumper. This is a significant gain as XF's lift balance was already best in class, and its low overall aerodynamic drag coefficient of only 0.29Cd contributes to both low wind noise and inherent high-speed stability.
The XF's body shell is already extremely stiff - in fact the stiffest in its class. This is key to the XF delivering superb ride and handling based on taut body control and precise, responsive steering. The bodyshell for the new MY 2010 Jaguar XF is even stiffer, thanks to a new rear subframe and the adoption of a boot cross-brace that was previously only fitted to the XF SV8 supercharged model.
Latest computer-controlled suspension and differential
The biggest changes in chassis dynamics for the Jaguar XFR, however, come from two new advanced technologies, Adaptive Dynamics and Active Differential Control, which are both incorporated as standard.
Active Differential Control (ADC) with traction-only functionality and handling functionality is an electronically controlled alternative to the traditional, wholly mechanical differential, offering more subtle control strategies.
ADC can vary its locking torque (and therefore the proportion of torque to each driven rear wheel) depending on surface conditions and power applied. Its control strategies optimise traction at each wheel, improving acceleration on low-grip surfaces while also enhancing cornering ability.
ADC has no adverse effect on either refinement or stability - where the traditional, mechanical differential can compromise stability under hard applications of power, demanding more corrective input from the driver. Whereas a mechanical differential is a permanently active part of the drivetrain, the Jaguar XFR's new ADC system is switched off when not required, so does not create undesirable understeer and creates no issues with NVH at lower speeds.
The differential is operated by an internal electric motor and 'ball-and-ramp' mechanism, and contains a multiplate clutch, which transmits or 'vectors' torque to the wheel with most grip. The multi-plate clutch assembly is designed to prevent excessive differential slip, but differs fundamentally from a conventional traction control which uses the brakes to counteract slip after it has occurred.
Continuously variable damping
Adaptive Dynamics, which replaces Jaguar's proven Computer Active Technology Suspension (CATS) on the Jaguar XFR, is a highly sophisticated active damping system which automatically adjusts suspension damper settings to suit both road conditions and the way in which the car is being driven. By removing the need for compromise between a fixed, softer setting for ride comfort and a fixed, firmer setting for tauter body control and handling, Adaptive Dynamics allows the balance between ride and handling to be optimised whatever the circumstances. Unlike earlier systems with only a small number of steps in the damper settings, it offers a progressively variable damping strategy between wide extremes, to deliver a comfortable but sporty ride with impressively sharp handling.
The three primary functions of Adaptive Dynamics are to control vertical movement, roll rate and pitch rate of the body. It does this by analysing induced body motions one hundred times a second, and setting each damper to an appropriate level in order to maintain a constant and level body attitude, thereby optimising control without compromising ride. Also one hundred times a second, it predicts the roll-rate due to steering inputs, and selectively increases damping forces to reduce that roll-rate - improving feel and driver confidence - as well as analysing fore and aft pitch rate due to throttle and braking inputs, and again varies damping forces to reduce pitch, further improving comfort and control.
Jaguar XFR also features Handling Functionality, which is unique in this class. In conjunction with the DSC Off option and JaguarDrive Control™ with Dynamic Mode, this supplements all the advantages of Traction Only Functionality with a number of more driver-focused dynamic characteristics. When selected, Dynamic Mode (which is also standard on the new naturally aspirated 5.0-litre V8 petrol and new 3.0-litre V6 diesel models) modifies the throttle, stability and transmission parameters, and on Jaguar XFR only it also modifies the Adaptive Dynamics responses. The combination of ADC and Dynamic mode with DSC Off allows controllable power-on oversteer, and improves off-throttle stability, allowing quicker, more spirited cornering. It can also improve stability in situations such as an emergency lane-change manoeuvre at high speed and, in combination with DSC, reduce the brake interventions which the more enthusiastic driver might see as intrusive.
