Audi Q7 4.2 TDI in Depth

Audi Q7 4.2 TDI

Power & Efficiency

By Text & Photos edited by Clinton Deacon
May 2, 2007 7:34 AM
Filed Under: Audi, German

Press Release

Audi is about to launch the most powerful diesel SUV in the world: the V8 in the Audi Q7 4.2 TDI, which will hit the showrooms in early summer, unleashes 240 kW (326 bhp) and 760 Nm of torque. The high-tech eight-cylinder unit impresses not only with its powerful performance, but also with its outstanding efficiency: it requires just 11.1 litres of diesel on average for every 100 kilometres driven.

At a glance

Engine

Power transmission

Suspension

Equipment

Body

Power and efficiency

Under the bonnet of the new Audi Q7 4.2 TDI is the most powerful V8 diesel engine that Audi has ever built. The eight-cylinder unit, which already powers the A8 luxury saloon, has a displacement of 4.2 litres and delivers 240 kW (326 bhp) and 760 Nm of torque - available constantly from 1,800 to 2,500 rpm. This gives the Audi Q7 4.2 TDI the performance of a sports car. It accelerates from zero to 100 km/h in 6.4 seconds and reaches a top speed of 236 km/h - these figures, too, are new records. The Audi Q7 4.2 TDI transmits its power through the six-speed tiptronic automatic transmission to a sportily tuned quattro driveline, which splits the propulsive force 40:60 between the front and rear wheels under normal driving conditions. Audi adaptive air suspension is standard on the top diesel model. It resolves a classic conflict of interests by combining dynamic handling with the ride comfort of a luxury-class vehicle. In the Audi Q7 4.2 TDI, the concentrated power of the mighty eight-cylinder diesel unit encounters a vehicle concept of versatile sportiness. Even on its debut the Audi Q7 set new standards in the SUV segment - now the 4.2 TDI is raising the bar even higher. The standard comfort and convenience equipment of the range-topping diesel model also take it to the top of the class. The leather design package lends the interior an air of subtle luxury; the electrically operated tailgate makes loading easier. A new technical feature is the optional Audi lane assist system, which alerts the driver by means of slight vibrations in the steering wheel if it detects that he/she is inadvertently crossing a lane marking on the carriageway without indicating.

The engine: concentrated pulling power

Like all engines in the Audi Q7 range, the eight-cylinder diesel power pack belongs to Audi's new V-engine family. The angle between the cylinder banks is 90 degrees, the spacing between cylinders 90 millimetres and its overall length a compact 520 millimetres. The large TDI unit, with a displacement of 4,134 cc, has a maintenance-free chain drive on the transmission side for the four camshafts and the ancillaries. The crankcase is made of vermicular graphite cast iron. The carbon in this high-tech material is integrated in lamella form. This gives the material superior strength and - typical for Audi - is an important factor in achieving the low weight for this performance category of 257 kilograms. The V8 TDI is a masterpiece of engineering and demonstrates the leading role that Audi has assumed in the diesel sector. Its crankshaft is forged from chrome-molybdenum alloy steel, while the pistons are made of cast aluminium. Electronically actuated flaps in the intake tract set the intake air into a controlled swirl, depending on load; low-friction roller cam followers actuate the 32 valves. Small, light piezo inline injectors that switch extremely quickly and with great precision are incorporated in the common rail injection system. They can achieve up to five injection phases per power stroke at an injection pressure of 1,600 bar. Two turbochargers with variable turbine geometry ensure ample torque at low engine speeds and impressive power at higher revs. Large intercoolers lower the temperature of the compressed air. The 4.2-litre TDI delivers an impressive 760 Nm of torque to the crankshaft, a figure which remains constant between 1,800 and 2,500 rpm. The driver can enjoy tremendous power reserves at any engine speed. At 3,750 rpm the V8 generates an output of 240 kW (326 bhp). Thanks to the world's most powerful V8 diesel engine in the SUV segment, the Audi Q7 also boasts the sportiest driving performance of all diesel units in its class. The performance SUV from Audi sprints from a standstill to 100 km/h in only 6.4 seconds and reaches a top speed of 236 km/h.

Driveline: dynamic character

Power for the Audi Q7 4.2 TDI is transferred as standard via the six-speed tiptronic automatic transmission. The dynamic shift program (DSP) manages the gear shifts and orientates itself towards the driver's style and the conditions on the road. A special sports program supports a particularly dynamic driving style. The driver can intervene in the procedure, either via the shift gate for the selector lever or via optional paddles on the steering wheel. Since the tiptronic was designed from the very beginning for high torque, it did not have to be specially reinforced to interact with the V8 diesel engine. Like all Audi Q7 models, the 4.2 TDI also has a self-locking centre differential, which features asymmetric/dynamic torque distribution. Under normal driving conditions it splits propulsive power in a ratio of 40 : 60 between the front and rear axle. If required, it delivers more to the rear or front axle, depending on the level of road grip: optimum traction is provided at all times. Ultramodern quattro technology provides for sporty handling, exceptional agility and remarkable steering precision.

Suspension: sporty performance

The suspension on the Audi Q7 4.2 TDI rounds off the dynamic personality of the vehicle. And it is equal to many a challenge - whether on rough terrain or on the road, where handling characteristics, driving safety and comfort set the standards. The adaptive air suspension, fitted as standard, completes the outstanding qualities. The combination of air suspension and electronically controlled damping with dynamic roll stabilisation creates a perfect synthesis of sportiness and superior ride comfort. The driver can select any of three settings for the adaptive air suspension: dynamic, comfort and automatic, ranging from sporty and firm to extremely comfortable. Together with the off-road and lift modes the system offers five different settings for the body ride height. In off-road mode, ground clearance is 205 millimetres - normally sufficient even for demanding terrain. For more convenient loading, the rear can be lowered by 71 mm. The basic suspension layout excels with its high level of sophistication. All four wheels are independently mounted on double wishbones; most of the axle components are made of aluminium. Servotronic steering with speed-dependent power assistance and variable ratio is exceptionally direct and precise, giving the driver a feeling of excellent road contact. The Audi Q7 4.2 TDI leaves the assembly line with sporty 18-inch alloy wheels and size 255/55 tyres. The four brake discs are internally ventilated and generous in size - they are 350 millimetres in diameter at the front axle and 358 mm at the rear. Six pistons in the front brake callipers apply brake pressure to each of the discs; this technology, too, hails from the world of the sports car.

Equipment: distinguished luxury

The new Audi Q7 4.2 TDI is furnished with a range of standard equipment that exudes an air of distinguished luxury. This includes the leather design package with a choice of inlays in aluminium or three types of wood and seat upholstery in Cricket leather. The front seats are electrically heated. An on-board computer, a cruise control system, a multifunction steering wheel and the much-praised operating system MMI basic further enhance comfort and convenience for the driver. The electrically operated tailgate is a practical solution: its opening angle can be programmed as required. Numerous assistance systems in the Audi Q7 4.2 TDI provide support for the driver. A new technology - Audi lane assist - is making its debut in the most potent diesel SUV on the world market. From a speed of around 65 km/h it alerts the driver by inducing a slight vibration in the steering wheel if he/she inadvertently moves out of the lane. If the driver has not indicated, the system issues the warning shortly before or while the vehicle is crossing the lane marking. Other high-tech systems offer even more comfort, convenience and control. Audi parking system advanced employs a camera to monitor the rear. The optional Audi adaptive cruise control is a radar-based system incorporating active distance control. It is combined with the brake assist system Audi braking guard. Audi side assist monitors the blind spot utilising radar technology and informs the driver if a vehicle approaching from behind could endanger the lane-changing manoeuvre. Countless interesting features are available to enhance the dynamic lines of the exterior and for the spacious interior of the 5.09-metre-long Audi Q7, from 21-inch wheels, the open sky system glass roof through to the rail system for the generous luggage compartment, which has a capacity of up to 2,035 litres. A deluxe automatic air conditioning system is standard; the seating system is exceptionally versatile. Like all Audi Q7 models the new 4.2 TDI is available as a 5, 6 or 7?seater. The new Audi Q7 4.2 TDI will be in showrooms in early summer. The basic price in Germany will be 70,500 euros.

Drivetrain

A sprint from zero to 100 km/h in 6.4 seconds and on to a top speed of 236 km/h – these figures illustrate the power of the Audi Q7 4.2 TDI, which is akin to that of a sports car. Its 90° V8 TDI draws on plentiful resources. The world’s mightiest diesel model in the SUV segment has superior pulling power on tap – at every speed and in every driving situation. The V8 transforms the Audi Q7 into a dynamic touring SUV with its serene and ultra-smooth operation, making long journeys a relaxed and supreme driving experience. On average, one full tank holding 100 litres is sufficient to cover 900 kilometres. The diesel, fitted as standard with a diesel particulate filter in compliance with the Euro 4 emissions standard, gets by on 11.1 litres per 100 km overall. The undersquare eight-cylinder TDI belongs to the new ultramodern V-engine family and is produced at the Györ plant in Hungary. With a bore of 83.0 mm and a stroke of 95.5 mm it has a displacement of 4,134 cc. It unleashes 240 kW (326 bhp) and a formidable 760 Nm of torque, which is available constantly between 1,800 and 2,500 rpm. The angle between cylinder banks on the range-topping TDI unit, which also powers the A8 luxury saloon, is 90 degrees, the spacing between cylinders 90 millimetres and its length a mere 520 millimetres. The crankcase is made of the high-tech material vermicular graphite cast iron, which is more rigid and more resistant to fatigue than grey cast iron. The graphite flakes produced during the casting process ensure that the microstructure elements are firmly interlocked. The relatively light crankcase forms the basis for the low weight of the engine – 257 kilograms – which enables a finely balanced distribution of mass between the front and rear axle. The crankshaft is forged from chrome-molybdenum steel; the pistons are made of cast aluminium. High-precision treatment of the bore surfaces using UV laser exposure reduces oil consumption to a minimum. The mighty TDI unit, housed beneath an elegantly styled bonnet, features a maintenance-free chain drive at the rear for its four camshafts and ancillaries. In the cylinder head, made of cast aluminium, low-friction roller cam followers actuate the 32 valves. Electronically controlled flaps in the intake tract set the intake air into a controlled swirl as required. At lower engine loads a high degree of swirl optimises combustion; at higher loads less swirl enables the combustion chambers to be filled to a high level. Both turbochargers – one for each cylinder bank – operate using electrically adjustable turbine geometry. Even at low engine speeds they provide solid torque and generate a relative boost pressure of up to 1.5 bar. Two large intercoolers lower the temperature of the compressed air, ensuring that the cylinders are filled more efficiently. The state-of-the-art common rail injection system features small, light piezo inline injectors, which respond extremely fast and with great precision by means of their electrically excitable piezo crystals. They can achieve up to five injection phases per power stroke. As a result, in conjunction with the robust engine construction and the particularly quiet valve gear, they make a vital contribution to the refinement of the high-tech diesel unit. Maximum injection pressure is 1,600 bar – this corresponds to the weight of a mid-size saloon on the area of a fingernail. The high pressure induces exceptionally fine atomisation of the fuel when it leaves the eight-hole nozzles. This ensures optimum mixture preparation and combustion and consequently high efficiency and low emissions.

Power transmission

The Audi Q7 4.2 TDI leaves the assembly line equipped as standard with the highly efficient tiptronic automatic transmission. Its six wide-spaced gears fully exploit the mighty pulling power of the diesel engine. Off-road, the torque converter with its damping action and torque multiplication is particularly useful when driving off and when driving slowly on inclines. A reduction gear is superfluous. The gear shifts are precise, spontaneous and harmonious in every situation. The tiptronic was designed from the very outset for high torque and is extremely well matched to the V8 diesel powerplant. Management of the tiptronic is taken care of by the dynamic shift program DSP, which orients itself to the individual style of the driver and to the prevailing road conditions. In the special sports program – S mode – the computer performs gear shifts later and faster when accelerating. The driver can take command at any time, either via the special shift gate on the selector lever or via optional paddles on the steering wheel. These manual shifts are particularly sporty. The Audi Q7 series employs the latest generation of the quattro permanent four-wheel drive. The self-locking centre differential – a purely mechanical planetary gear – provides fast asymmetric/dynamic torque distribution according to available traction at the front and rear axle: under normal driving conditions the front axle is assigned 40 per cent of the propulsive force, the rear axle 60 per cent. If required, the differential can deliver up to 65 per cent to the front or up to 85 per cent to the rear. If a wheel at one axle starts to spin, the electronic differential lock EDL controls distribution between left and right by means of brake intervention. The quattro drive in the Audi Q7 4.2 TDI provides optimum grip, safety and driving enjoyment in every situation. Its sporty basic setting produces exceptional agility that sets the benchmark – and not just in the SUV segment.

Suspension

The Audi Q7 4.2 TDI features a dynamic suspension that is equal to the magnificent performance of the engine in every situation. Off the beaten track it offers outstanding off-road capabilities, on the motorway precise directional stability and supreme control. And on winding country lanes the large SUV from Audi impresses with safe, precise and agile handling characteristics that set new standards. The most powerful diesel SUV in the world runs on 18-inch forged alloy wheels with sporty 255/55 tyres. Most of its suspension components are made of aluminium. All four wheels are mounted on double wishbones that in turn are attached to subframes. The servotronic steering conveys a feeling of excellent road contact thanks to its remarkably direct and precise response. Two high-tech solutions work together here: power assistance is reduced as the vehicle speed increases and the ratio varies between around 10.0:1 and 16.5:1, depending on steering angle. When steering out of the straight-ahead position the response is more indirect, which guards against any nervous reactions at high speeds; with wider steering angles the response is more direct to convey an active driving feel. The Audi Q7 4.2 TDI illustrates Audi’s claim to always offer the optimum technical solution. It comes as standard with adaptive air suspension. This combines air suspension with an electronically controlled damping system incorporating dynamic roll stabilisation. In this way it unites dynamic, sporty handling with supreme ride comfort. The driver can select any of three settings for the adaptive air suspension via the operating system MMI basic – namely dynamic, automatic and comfort – from very sporty to extremely comfortable. The control unit varies the characteristic curves of the shock absorbers and air springs accordingly; the bellows of the latter are made from a specially structured multi-ply material for a sensitive response. The road speed is also incorporated in the control strategy. At the same time, the system allows ground clearance to be adjusted from the normal level of 180 mm to an additional four positions. On the motorway, the body is automatically lowered to 165 mm from a road speed of 120 km/h – maintained constantly for more than 30 seconds – and to only 150 mm from 160 km/h (more than 20 seconds). This increases stability while reducing aerodynamic drag – maximum speed is higher and fuel consumption is lower. On country lanes, handling benefits from the dynamic roll stabilisation function. This responds to steering input and body roll and counteracts the rolling motion by deliberately increasing the damping forces. In off-road mode, which can be used up to 100 km/h, ground clearance is 205 mm. In lift mode (240 mm) the Audi Q7 can negotiate more significant obstacles at moderate speeds. When the vehicle is stationary, the loading sill can be lowered to 71 mm via a button in the luggage compartment for easy loading. The adaptive air suspension also functions as a self-levelling suspension – it keeps the body at the ideal height in every situation, regardless of load. The sensitive response of the ESP stabilisation program on the Audi Q7 4.2 TDI ensures maximum safety. It features special functions for off-road and downhill driving; in addition, it stabilises a towed trailer at risk of fishtailing by applying targeted braking impulses. The four discs in the hydraulic brake system are internally ventilated and of optimum size; the front brake callipers feature six-piston technology, as found on a sports car. A tyre pressure monitoring system, which sends a warning message to the display in the central instrument cluster in the event of pressure loss, is available as an option.

Body

The powerful, elongated design with its sculptured, curved surfaces epitomises the independent character of the Audi Q7. The flowing, wide sweep of the roof line and the striking contrast between the very high lateral body surfaces and the flat window area give a clear indication of the sporty nature of the performance SUV. The front section is sharply tapered; at the rear, steeply angled D-pillars convey an impression of extreme dynamism and encase a coupé-like silhouette. The shoulder line and dynamic line, which define the side sections, are further classic elements of Audi’s formal idiom. The tailpipes, arranged symmetrically, are 100 mm in diameter. Below the right tail light, a badge identifies the most powerful diesel engine ever produced by the Audi brand. For an even sportier appearance, two packages are available – the S line exterior package and the S line sports package plus; aluminium wheels of up to 21 inches in diameter are also available. Those who prefer a more rugged look can choose between three off-road style packages. Here Audi offers the option of 235 R 18 off-road tyres and running boards in stainless steel. Xenon plus headlights, dynamic cornering light and daytime running lights are combined in the high-tech extra adaptive light. The Audi Q7 4.2 TDI, with a wheelbase measuring 3,002 millimetres, is 5,086 mm in length, 1,983 mm wide and 1,737 millimetres high. These dimensions put the Audi Q7 ahead of the competition in its category. With a lightweight steel construction using high-strength and ultra-high-strength steels and aluminium, its body meets the highest requirements in terms of rigidity and crash safety. Inside, too, the Audi Q7 reflects the classic standards of the Audi brand – uncompromising craftsmanship and ease of use. Its architecture is clearly structured with powerful taut lines and a generous division of space. All the materials for the interior have been selected and crafted with the utmost care. Numerous storage facilities are provided – including a bottle holder in each of the four doors and two cup holders for each seat row. On request, Audi equips the vehicle with a four-zone automatic air conditioning system and the large three-part open sky system glass roof. The performance SUV opens up a new dimension in versatility – it permits no less than 28 seating and loading configurations. The Audi Q7 is fitted as standard with five seats. In the second row, the backrest angle is adjustable; the centre section can be used as a load-through facility. On request, the seats can be provided with fore/aft adjustment, creating the longest legroom in this vehicle segment. As a six-seater, the Audi Q7 features two luxurious individual seats in the second row. On the optional seven-seater, seven occupants are accommodated in three rows. Thanks to an intelligent mechanism the two rear seat rows can be folded flat, increasing the luggage capacity from 330 to 2,035 litres. As a five-seater the Audi Q7 boasts an impressive 775 litres of load capacity as standard, a load-through width of 116 cm and a double load-area floor with dirt-resistant tray. For sports enthusiasts a rail system, a ski bag and a cycle rack are available. With the optional tow hitch – electrically operated on request – the Audi Q7 4.2 TDI can pull a braked trailer weight of up to 3.5 tonnes.

Equipment

At its launch the Audi Q7 set new standards in the large SUV segment. Now the 4.2 TDI is raising the bar even higher. This also applies to the equipment featured on the new range-topping diesel model when it leaves the assembly line. The array of standard equipment includes the leather design package, for which the surfaces have been carefully coordinated to complement each other. It features seat upholstery in coarse-grained Cricket leather and inlays in silver aluminium or the wood options Walnut natural, Tamo ash dark brown (Japanese ash) and Olive ash beige. The air vents are finished in aluminium look, the footwell is lined in velour or Fresco carpet. Eight further optional design packages are available for selection. A range of other standard features rounds off the luxurious, sporty character of the Audi Q7 4.2 TDI. The front seats are heated; an on-board computer places all the important information in the driver’s field of vision and a cruise control system provides even more comfort and convenience. The radio system, and optionally the mobile phone and speech control system, can be operated via the multifunction steering wheel. The 18-inch forged aluminium wheels of seven-arm design come with sporty 255/55 tyres. The tailgate is opened and closed via two electric motors; its opening angle can be programmed according to requirements. The tailgate is made of aluminium and reaches into the side sections – an elaborate construction made possible by the brand’s expertise in aluminium design. Like all Audi Q7 models, the new 4.2 TDI is also equipped with many other features that make driving more comfortable and safer. These include six airbags, energy management for the battery, roof rails made of aluminium, a partition net, a deluxe automatic air conditioning system – which is extremely quiet and draught-free – with separate controls for the left and right, as well as the much-praised operating system MMI basic incorporating a CD audio system. This can be enhanced in three stages through to the high-end info centre including a navigation system. New in the Audi Q7 4.2 TDI is another state-of-the-art assistance system – Audi lane assist. This lane-monitoring assistant, which can be ordered together with the four-spoke multifunction steering wheel, alerts the driver from a speed of around 65 km/h – i.e. on out-of-town roads – if he/she is about to inadvertently move out of the lane. A camera observes the road in front of the car and the system identifies the lane markings. If the system is activated and the driver has not indicated, a warning is issued shortly before or while the driver is crossing the identified line on the carriageway by means of slight vibrations in the steering wheel. The warning point can be set via the Audi MMI to any of three stages, namely early, adaptive and late. The system issues the warning with the respective level of sensitivity, according to the chosen setting and angle of approach to the identified lane marking. Audi lane assist is the latest development in the field of assistance systems, where the brand has already undertaken a great deal of pioneering work. A radar-based cruise control system with active distance control operates under the name adaptive cruise control. It functions between 0 and 200 km/h and is combined with the braking guard brake assist system, which alerts the driver in two stages if there is a risk of a bumper-to-bumper collision. Audi side assist utilises radar technology to monitor the blind spot as well as fast-approaching vehicles and, by means of LEDs in the base of the exterior mirrors, indicates any vehicle it has detected that could make a change of lane hazardous. Audi parking system advanced employs a rear-view camera and relays its captured image to the MMI screen; coloured lines and zones help the driver to manoeuvre into parking spaces. In the area of entertainment Audi offers a complete system of modules. These include the Audi music interface: the latest iPods from Apple as well as mp3 players can be plugged in via USB connectors. Hi-fi fans can enjoy a highly exclusive special option – a sound system from the Danish specialists Bang & Olufsen, which will be available to order in the second half of the year. The B&O system excels not only with its high-end sound quality, it also stands out – as is typical for the Danish brand and for Audi – by virtue of its fine design and superb craftsmanship. 14 active speakers, special Acoustic Lens Technology from Bang & Olufsen and - thanks to sophisticated amplifier technology - more than an incredible 1,000 watts of amplification create a sound experience of captivating three-dimensionality and finesse. The Audi Q7 4.2 TDI will be in showrooms in early summer. Its basic price in Germany is 70,500 euros.