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Biturbo V8 with titanic torque – the new Audi SQ8 TDI

Biturbo V8 with titanic torque – the new Audi SQ8 TDI
The top tier Audi luxury SUV is about to show a harder-edged side to its character as a brawny V8 TDI with 435PS and 900Nm of torque thrusts its performance squarely into ‘S’ model territory – the new SQ8 TDI becomes available to order in the UK next month in ‘standard’ or exhaustively equipped Vorsprung forms, the latter marshalling the copious power with the help of all-wheel-steering, the quattro sport rear axle differential and active roll stabilisation made possible by the car’s advanced 48-volt circuitry.

Power and efficiency: 4.0 TDI with electric powered compressor
The 4.0-litre biturbo V8 in the Audi SQ8 TDI will be notable as the most powerful diesel engine available on the European market. It combines its potency with a high level of economy and integrates a whole package of high-tech solutions. The engine delivers 435PS and a mammoth 900 Nm (663.8 lb-ft) of torque between 1,250 and 3,250 rpm, credentials that enable it to propel the SQ8 like a sports car: acceleration from rest to 62mph requires just 4.8 seconds, soon after which the electronic propulsion limit kicks in at 155mph. The power of the V8 engine is emphasised by an engine cover specific to the S model series. Red applications flank the striking contours of the cylinder and visualise the air ducting.

In the eight cylinder heads, the intake side is on the outside and the hot exhaust side with the two turbochargers is in the inner “V.” As a result, the gas travel paths are short, working in favour of immediacy of response. The turbos are operated according to the principle of sequential turbocharging. Only one charger is active at low engine speeds; the second charger exerts its influence from around 2,200 rpm. The sonorous sound of the eight-cylinder engine is amplified by a sound actuator in the exhaust system, which drivers can adjust to their personal preferences via Audi drive select.

An electrically powered compressor (EPC) assists the turbochargers when starting off and when accelerating at a low engine speeds. It is located in a bypass behind the intercooler and is activated when the flap is closed. If the load requirement is high while the amount of energy available in the exhaust gas is low, the intake air flows into the EPC, where it is compressed a second time. It thereby ensures consistently strong power delivery and excellent overtaking capability.

The driving force behind the EPC is the 48-volt main on-board electrical system, which is also the backbone of the mild hybrid system (MHEV). A compact lithium-ion battery serves as its energy storage unit. The belt alternator starter (BAS), which is connected to the crankshaft, allows up to 8 kW of recuperation power to be generated during deceleration and can feed this energy into the battery. If the driver lifts off the accelerator at speeds of between 34mph and 99mph, the Audi SQ8 TDI can, depending on the situation, either recuperate, travel with the engine at idle, or coast with the engine completely deactivated for up to 40 seconds. The BAS restarts the engine the next time the accelerator is depressed, and does so faster and more gently than a conventional starter. It also raises the operating threshold of the start/stop function, enabling the engine to be deactivated at speeds of 13mph and below. The system thereby contributes to the high level of efficiency of the SQ8 TDI. In customer operation, MHEV technology reduces consumption by up to 0.5 litres per 100 kilometres.

Sport differential, all-wheel steering and roll stabilisation for Vorsprung models
Power transmission in the Audi SQ8 TDI takes place via an eight-speed tiptronic transmission. Its dual-mass flywheel integrates a torsional absorber that adapts to the engine speed and compensates for the vibrations of the V8 diesel at very low engine speeds. Detailed solutions such as a clutch in the central transmission and an electric oil pump enable the automatic transmission to work together with the MHEV technology. The quattro permanent all-wheel drive system distributes the drive forces between the front and rear axles in a 40:60 ratio. The sport differential which is fitted as standard to UK Vorsprung models complements its work by actively distributing torque between the rear wheels. When cornering, it is predominantly channelled to the wheel on the outside – the Audi SQ8 TDI is literally pressed into the bend, minimising the potential for understeer. In case of oversteer, the sport differential stabilises the large SUV coupé by shifting torque to the wheel on the inside of the bend.

As standard, the SQ8 TDI is equipped with the Audi drive select dynamic handling system with seven modes and the adaptive air suspension sport with regulated damping. The air suspension changes the ride height as needed by as much as 90 millimetres. In the UK the SQ8 TDI Vorsprung also supplements this with all-wheel steering and active roll stabilisation.

At manoeuvring and parking speeds the all-wheel-steering system turns the rear wheels in the opposite direction to reduce turning effort, and then at speeds upwards of 37mph turns them slightly in the same direction to improve steering response and further increase stability when cornering.

The electromechanical active roll stabilisation system employs a compact electric motor positioned between the two sections of the anti-roll bar on each axle. When driving straight ahead, the sections of the anti-roll bar are decoupled, which reduces body movement on uneven roads and also increases tyre comfort. During more committed driving, when the focus is on optimum roll compensation, the sections are twisted in opposite directions, making the handling of the SQ8 TDI firmer. The vehicle’s roll angle in bends is also reduced considerably. The electromechanical active roll stabilisation is integrated in the 48-volt main on-board electrical system and serves as a recuperating system. It can generate power via the electric motors and thereby feed energy back to the battery.

S-specific details: Design and interior
Taut, muscular surfaces and a coupé-like roof line embody the dynamic character of the Audi SQ8 TDI, and the octagonal singleframe, pronounced quattro blisters above the wheel wells and striking underbody protection help to underline its statement of intent. Standard HD Matrix LED headlights illuminate the road, and the three-dimensional signature of the daytime running lights and the tail lights displays a digital character. Horizontal lines, including the light strip on the rear which is a characteristic of all the high-end Audi models, emphasise the width of the SUV coupe, while design details specific to the S version also convey its special rank in the range.

The singleframe is structured by double louvres and surrounded by a matt silver frame. The bracket that runs below it and the heavily contoured air inlets, the underbody protection and the inlays in the side sills are finished in the same colour, as are the door mirror housings. At the rear, the honeycomb grid insert and the diffuser in matt titan black catch the eye – the latter integrates silver underbody protection that is flanked on both sides by the two round exhaust tailpipes. Vorsprung versions are also marked out by a black styling package that accentuates the area of the bumpers, the singleframe and the side windows.

With its three-metre wheelbase, the Audi SQ8 TDI provides a generous amount of space. The interior features a clear design that is dominated by horizontal lines. Super sport seats with integrated head restraints and pronounced side bolsters are standard, and in the SQ8 TDI Vorsprung incorporate climate control and massage functions. The three-seat system in the rear can be moved forwards and backward as desired and when it is positioned in favour of luggage stowage and its backrests are folded forwards, the luggage compartment has a 1,755-litre capacity; with all seats fully in place it holds 605 litres. An electrically operated tailgate features as standard.

As is typical for an S model, the interior is primarily finished in black, with diamond stitched black Valcona leather upholstery, but the seats, the front centre armrest and the door armrests can be trimmed in rotor grey or Arras red as an option. Depending on the upholstery choice, the seats feature either rock grey or anthracite contrast stitching. Inlays are aluminium in the SQ8 TDI and carbon in the SQ8 TDI Vorsprung, with the option to switch to carbon or choose an oak grey finish as an alternative in the ‘standard’ car. Illuminated door sill trims with aluminium inlays and the S logo at the front are part of the standard equipment, as are the stainless steel pedals and footrest.

Intelligently connected: Operation and infotainment
The Audi SQ8 TDI has two large touchscreens with haptic and acoustic feedback as its main operating elements. The upper display, which is integrated in a large high-gloss black bezel and is almost invisible when it is switched off, is used to control the infotainment and navigation systems. The driver uses the lower display for managing the heating and air conditioning, convenience functions, and text input, the latter with his or her wrist resting comfortably on the selector lever if desired.

The Audi SQ8 TDI is also equipped with a natural language control feature that even understands freely formulated commands and questions. To respond, the system uses information stored on board, such as the driver’s preferred navigation or special destinations, on the one hand and knowledge from the cloud on the other hand. While the online cross-referencing improves the recognition rate and quality of the results, the advantage of the onboard data relates to its rapid, reliable availability – even in the absence of a mobile network, say in an underground parking garage.

In addition to the two touchscreens, the digital instrument cluster displays a great deal of detailed information. The driver can use the view button on the multifunction steering wheel to switch between two views in the Audi virtual cockpit: While the tachometer and speedometer are displayed as large dial-type gauges in driving mode, the map is the centre of attention in infotainment mode. Both views have S-specific red graphical details. A performance layout where the central focus is the tachometer, displayed as a square graph, and the performance and torque are shown as percentages, can also be selected in the MMI. When the large navigation map is shown, the torque and speed are displayed as small bar graphs. In addition, the SQ8 TDI Vorsprung features a head-up display which can project important information relating to route guidance onto the windscreen.

The top-of-the-line MMI navigation plus infotainment system is a standard feature of both versions of the Audi SQ8 TDI. It has an integrated data transfer module that supports the LTE Advanced standard. The navigation system features many intelligent functions. For example, it recognizes the driver’s preferences based on previous journeys and can therefore make intelligent suggestions. Calculations are performed online on the servers of map and navigation service provider HERE.

The online services from Audi connect complement the route-planning process. The customer can select points of interest such as parking garages or attractions in the navigation map and see photos, opening hours and ratings, for example. The Car-to-X services, online traffic sign information, hazard alerts, and on-street parking, all of which use the swarm intelligence of the Audi fleet, are also part of Audi connect.

Traffic light information is a new feature that will gradually become available in cities across Europe. Thanks to its connectivity with the city’s infrastructure, the vehicle receives information from the central traffic light computer via a server, which allows the driver to select a speed to match the next green-light phase. The Audi virtual cockpit displays an individual speed recommendation as well as the remaining time until the next green-light phase if the driver is already waiting at a red light. The system thereby contributes to a predictive and efficient driving style and facilitates a steady flow of traffic.

The connect portfolio also includes the cloud-based Amazon voice service Alexa, which is integrated into the MMI operating system. The driver can use it to place orders and get information on various current events. Alexa streams music and audiobooks and provides access to over 80,000 Alexa Skills. The smart home control allows users to lock doors in the house, adjust the lighting, and close the garage door from within the car.

The SQ8 TDI is fully compatible with the myAudi app, which seamlessly connects the vehicle with the customer’s smartphone. That device can also make its key infotainment apps available on the onboard MMI screen via the standard Audi smartphone interface for iOS and Android smartphones. This can even be done wirelessly with the iPhone, as can Qi-enabled smartphone battery charging via the standard Audi phonebox unit. For pure entertainment value, the Bang & Olufsen 3D Premium Sound System that is a standard feature in Vorsprung versions has been designed to exceed the expectations of audiophiles – it can also be specified as an option for the ‘standard’ car. 

Getting to your destination safely: the assist systems
A broad portfolio of assist systems complements the extensive offer of services in the SQ8 TDI. To bolster safety when driving in the city cross traffic assist front and rear, exit warning and active lane assist are fitted as standard to the SQ8 TDI Vorsprung and optional for the SQ8 TDI. Adaptive cruise assist is an option for both versions, making longer journeys more relaxed by assisting with longitudinal and lateral guidance. It incorporates the functions of adaptive cruise control, traffic jam assist, and active lane assist. In conjunction with the efficiency assistant, the system predictively slows down and accelerates the Audi SQ8 TDI based on its evaluation of sensor information, navigation data, and road signs.

Behind all these systems lies a high-tech module from Audi: the central driver assistance controller, or zFAS for short. The tablet-size computer, which is on board the SQ8 TDI as standard, constantly calculates a differentiated image of the environment. This central environmental model enables the assist systems to react precisely and in good time to objects, such as by initiating braking. Navigation is also highly precise because the sensor data fusion locates the driver’s car down to the exact lane. Depending on the selected options, the zFAS receives the data to do this from up to five radar sensors, five cameras, and twelve ultrasound sensors.