Audi RS 6

For the C5 RS6 powertrain detail, the engine is an all-aluminium alloy 4,172 cubic centimetres (254.6 cu in) twin-turbocharged ('biturbo'), double overhead camshaft, 5 valve per cylinder version of Audi's 4.2-litre 90° V8 petrol engine (parts code prefix: 077, identification code: BCY), developed and manufactured in Germany and the UK by quattro GmbH and Cosworth Technology (now known as MAHLE Powertrain). With the addition of the two turbochargers (one per cylinder bank), the power output of the V8 engine was increased to 331 kW (450 PS; 444 bhp) at 5,700 to 6,400 rpm, and generated 580 N⋅m (428 lbf⋅ft) of torque. The combination of the 4.2-litre V8, variable inlet valve timing, and twin turbochargers gave the RS6 an exceptionally wide power band, with peak torque available from 1,950 to 5,600 rpm.

Further detail of the engine includes fully sequential electronic multi-point fuel injection with intake manifold-sited fuel injectors,[4] mapped direct ignition system[5] with solid-state high voltage distribution using eight individual single-spark ignition coils and NGK longlife spark plugs, and three knock sensors. Engine management uses a Bosch Motronic[6] ME 7.1.1 engine control unit, which controls all functions of the engine operation; including fuel delivery, ignition system, valve timing, emissions control systems, and torque reduction control—the latter operating in conjunction with the Bosch ESP 5.7 Electronic Stability Programme, as part of the "Anti Slip Regulation" (ASR) traction control system. The engine is compliant with the European Union Euro3 (EU3) standard, and includes two close-coupled primary catalytic converters (CATs), two underfloor main CATs, and four heated oxygen sensors which manage the cylinder bank selective lambda control. This results in a CO₂ emissions rating of 350 g/km for the Avant and saloon in standard configuration.

It has an electronically controlled five-speed ZF 5HP24A tiptronic automatic transmission (parts code prefix: 01L, identification code: GAG) (gear ratios—1st: 3.571, 2nd: 2.200, 3rd: 1.505, 4th: 1.000, 5th: 0.804), with lock-up torque converter in all forward gears. It has "hill detection" capability, and, despite many press articles stating that the gearbox was programmed to "blip" the throttle for downshift gear changes, no UK owners have ever found this feature to be present. The transmission control unit ECU incorporates "fuzzy logic" with its "Dynamic Shift Programme" (DSP), with the shift pattern adapting to suit individual driving styles. 'Tiptronic' manual control can be achieved with either the floor-mounted gear shift lever, or the steering wheel mounted 'paddles'.

The RS6 was only available with Audi's Torsen-based quattro permanent four-wheel drive, utilising the Torsen T-2 dynamic 'automatic torque biasing' (ATB) centre differential (diff), a modified unit which was being used in the 6.0-litre W12-powered Audi D3 A8. The torque from the engine is first routed from the gearbox output shaft to the Torsen centre diff, and then automatically divided and apportioned between the front and rear axles.

The front and rear axle differentials (ratio: 3.197, rear axle identification code: GGW) are a conventional "open" type, but utilise an "Electronic Differential Lock" (EDL). EDL is an integrated additional function of the Bosch Electronic Stability Programme (ESP) system, and works by monitoring and comparing the individual wheel speeds across an axle, and braking an individual wheel which is sensed to have lost traction (spinning), thus transferring torque across the axle to the wheel/tyre which does have grip. "Anti-Slip Regulation" (ASR), more commonly known as traction control system[7] completes the Bosch ESP-related driver aids.

Utilising the same fully independent four-link front suspension, and double wishbone rear, as its related A6 and S6, the RS6 was lowered by 20 millimetres (0.79 in), with a 30% stiffer spring rate, and 40% increased compression damping. The RS6 also served as the debut model for Audi's "Dynamic Ride Control" (DRC) system. The DRC system is mainly mechanical, and uses a pump to provide additional pressure to individual dampers (shock absorbers) during cornering, acceleration or braking; to counteract rolling and pitching. The system can adjust the stiffness at each individual damper constantly; to maintain both a comfortable ride on straight roads, and high level of poise and grip when cornering hard, accelerating, or braking. The DRC's main advantage is that it operates without the need for complicated electronics, as required in similar systems from Mercedes-Benz and other competitors. Its main drawback is that the DRC dampers have been known to fail (leaking fluid from the cross-linked circuits), which can affect the handling and ride quality of the vehicle; some owners have reported needing multiple replacements of faulty DRC units and many drivers have opted to replace the system with simpler and more reliable aftermarket coilover suspension.

The front brakes feature fixed Brembo 8-piston monoblock brake calipers, working with radially vented and cross-drilled brake discs, sized at 365 millimetres (14.4 in) in diameter, by 34 mm (1.34 in) thick. The rear features single-piston floating ATE calipers with integrated cable-operated parking brake mechanism, mated to radially vented disc and cross-drilled, sized 335 mm (13.2 in) by 22 mm (0.87 in). Front and rear brake calipers are finished in a high-gloss black paint, with the fronts incorporating the Audi "RS" logo. Both front and rear discs are held in by metal pins to the lightweight disc hub, and allow 1.0 mm (0.039 in) of lateral thermal expansion from the hub centre.

Bosch ESP 5.7 Electronic Stability Programme,[8] with Anti-lock Braking System (ABS),[9] Electronic Brakeforce Distribution (EBD), and Brake Assist (BA) was standard fitment.

There were total of three original equipment manufacturer (OEM) wheel and tyre types produced for the RS6. In Europe and elsewhere, 19-inch wheels were standard, with an optional 18-inch package. In the U.S. market, the 18-inch package was the only available offering. An 18-inch winter package, with Dunlop SP Winter Sport M3 tyres (225/45 ZR18 95V) was universally available.

For 18-inch wheels, the standard tyre fitted was 255/40 ZR18 99Y XL with eXtraLoad (XL) rating. This is often stressed, and is the only recommendation by Audi, as RS6 does weigh 1,865 kg (4,112 lb). Tyres which are not rated XL are not safe (nor legal, in most countries) for use. Owners reported finding Continental ContiSportContact 2, Dunlop SP Sport 9000, Michelin Pilot Sport PS2, and Pirelli P-Zero Rosso as OEM suppliers for tyres on the RS6. However, according to ETKA, the Dunlop and Pirelli tyres were subsequently withdrawn from official supply, and the Continental SportContact 2 has been superseded by the SportContact 3. An additional tyre from Bridgestone has now been included as officially recommended fitment, the Potenza RE050A.

For 19-inch wheels, the standard tyre fitted was 255/35 ZR19 96Y XL. However, there were debates as to how safe 19-inch (48 cm) wheels and tyres are, as the XL rating achieves a 96 Load Index (710 kg (1,565 lb) load rating). In contrast, the 255/40 ZR18 XL will get you 99 Load Index, good for 775 kg (1,709 lb) per tyre. Current officially recommended tyres from ETKA for the 19-inch rims only include the Michelin Pilot Sport PS2, Continental ContiSportContact 3 and Vredestein Ultrac Sessanta also 96Y XL.

Audi RS6 Plus, showing the 'black optics' and anthracite alloy wheels

Between April 2004 and September 2004, there was a final limited run of an even higher-performance RS6, named the Audi RS6 Plus. This had an increased engine power output (identification code: BRV), and produced 353 kW (480 PS; 473 bhp) at 6,000-6,400 rpm, with the same 580 N⋅m (428 lb⋅ft) of torque at 1,950-6,000 rpm. This engine was also developed and manufactured in the UK by Cosworth Technology (now known as MAHLE Powertrain). The additional performance was achieved with a new engine control unit (ECU), and two additional coolant radiators behind the side-mounted intercoolers (these were standard fitment on the standard RS6 in hotter climate countries). Official performance figures indicate the discipline of sprinting from standstill to 100 km/h (62.1 mph) in 4.4 seconds. The RS6 Plus carries on to reach 200 km/h (124.3 mph) in 20.36 seconds, and has an official top speed of 280 km/h (174.0 mph).

The RS6 Plus came with Dynamic Ride Control (DRC) as standard, and also included a no-cost option of "Sports Suspension Plus", which lowered the standard sports suspension by a further 10 millimetres (0.39 in) over the standard RS6. A revised steering rack, with a reduced ratio of 14.3 for firmer steering feel was included, and resulted in a turning circle of 11.7 metres (38.4 ft). The brakes now included cross-drilled discs. The wheels were only available in the 9Jx19-inch '5-arm design' alloys, finished in "anthracite" (dark grey), with 255/35 ZR19 96Y XL tyres.

The car was available only as an Avant, and was sold only in European markets. Visual differences for the RS6 Plus included the "black optic pack", which consisted of black finish to the framing of the radiator grille, exterior window trims, tailgate lower trim, roof rails, and exhaust tailpipes. It quickly sold out once it was released (999 units total). The last three digits of the Vehicle Identification Number (VIN) are reproduced on a plaque inside the car, displayed on the centre console.

Champion Racing Audi RS6 Competition

The RS6 was used in the North American SPEED World Challenge GT Series of auto racing for three years - 2002 to 2004, claiming the manufacturers' championship victory successively in all three years.[10] Once again, the special race derivative of the twin-turbo V8 engine was developed and manufactured in the UK by Cosworth Technology (now known as MAHLE Powertrain). However, the 2005 season proved difficult due to performance restrictions imposed on Champion Audi Racing by the Sports Car Club of America (SCCA), with Champion deciding to run a different wheel diameter, and the trade-off was reducing boost pressure.

The RS6 was challenged by a factory-backed Cadillac CTS-V, but was still victorious. Champion Audi Racing decided to pull the RS6 from the series, citing unfair rules and regulations that targeted the dominant Audis.

Audi RS6 Avant quattro (C6)

The C6 RS 6 Avant was launched in April 2008, and the four-door saloon/sedan was available from August 2008. Constructed from steel in a monocoque (unibody) design, the RS 6 uses lightweight aluminium for its front wings (fenders) and bonnet (hood).

Visually, the RS 6 differed from the related S6, having flared front and rear wheel arches (fenders), harking back to the original Audi Quattro, to allow for a wider wheel track. It also had no front fog lights to allow for larger frontal air intakes (for the two side-mounted intercoolers (SMICs), and additional radiators). The ten (per side) front light-emitting diode (LED) daytime running lights (DRLs) are located within the main headlamp housing on the RS 6 in order to increase the size of the air intakes, whereas similar LEDs (but five per side) on the related S6 are found adjacent to the fog lamps in the lower front bumper. LED lighting technology was also used in the rear lights. The RS 6 also included adaptive headlights, which swivel around corners in conjunction with steering wheel movements. The facelifted Audi A6, released as a 2009 model, received similar front and rear-end LED lighting styling to that pioneered on the RS 6.

Luggage capacity, measured according to the VDA 'block method' in the Avant ranges from 565 litres (19.95 cu ft), to 1,660 litres (58.62 cu ft).

The engine (parts code: 07L, identification code: BUH) of the RS6 was what Audi claimed to be the first all-aluminium alloy even firing 5.0-litre (4,991 cc (304.6 cu in)) 90° V10 twin-turbocharged ("biturbo"), Fuel Stratified Injection (FSI), with a dry sump lubrication system. This engine is related to the naturally-aspirated V10 found in the Audi R8, S6 and S8, and the Lamborghini Gallardo, but the RS 6's engine has around 400 unique parts[11][19].

The engine has four valves per cylinder, with chain-driven double overhead camshafts, and variable valve timing[22] for both inlet and exhaust camshafts. Charged intake air is cooled by two side-mounted intercoolers (SMIC)s. The engine is controlled by two Bosch DI-Motronic[23] MED 9.1.2 engine control units, which act as 'master' and 'slave': two ECUs are required due to the high revs the engine can achieve. It also uses mapped direct ignition system with ten individual direct-acting spark coils, an electronic drive by wire throttle (Bosch "E-Gas"),[24] cylinder-selective knock control, and cylinder bank adaptive lambda control, utilising eight lambda sensors.

A total of seven radiators, and four electric cooling fans are needed to cool the engine and related components under the aluminium bonnet of the RS6.

Drive output passes through a ZF 6HP28A six-speed tiptronic automatic transmission. The gear ratios are: 1st: 4.171, 2nd: 2.340, 3rd: 1.521, 4th: 1.143, 5th: 0.867, 6th: 0.691, with shortened shift times, with "Dynamic Shift Programme" (DSP) and "Sport" mode. It has paddle-shifts mounted behind the flat-bottomed steering wheel, similar in design to the Audi B7 RS 4. The gearbox is set by default, in conventional automatic mode, to delay up-changes during acceleration, and change down earlier to maximise engine braking. Downchanges in all modes of operation include the Powertrain Control Module electronic control unit (ECU) "blipping" the Bosch "E-Gas" drive by wire throttle, for smoother shift changes. The hydraulic torque converter includes a lock-up function in all forward gears, and is able to completely disconnect when the vehicle is stationary, thus saving fuel.

Like all Audi "RS" models, the RS 6 is fitted with Audi's 'trademark' quattro permanent four-wheel drive as standard. This version of the RS 6 uses the latest asymmetric dynamic 40:60 front-to-rear default torque distribution from the Torsen T-3 'automatic torque biasing' (ATB) centre differential. This latest incarnation of the Torsen quattro, first seen in the B7 RS 4, can automatically dynamically apportion up to a maximum 100% torque to the rear axle, or up to 80% to the front, dependent on traction conditions.

The front and rear final drives are conventional "open" differentials (ratio 3.317), and use the Audi "Electronic Differential Lock" (EDL). EDL is a part, or "function", of the Bosch ESP 8.0 Electronic Stability Programme,[8] which also includes "Anti-Slip Regulation" (ASR) traction control system. EDL does not 'lock' the differential in a traditional sense, but uses electronics to compare the speeds of the two wheels on an axle, and brakes any wheel that is sensed to have lost traction (by rotating faster than the opposite wheel, beyond normal accepted deviations). This braking of a slipping wheel has the effect of transferring torque across the axle to the other wheel, which is assumed still to have traction.

Like the previous RS6 and the B7 RS 4 this generation of RS 6 includes Audi's "Dynamic Ride Control" (DRC) Sports suspension system. The system is mainly mechanical, using a pump to provide additional pressure in the diagonally linked dampers (shock absorber) during cornering, to counteract rolling and pitching. The system can dynamically adjust the stiffness at each damper constantly to maintain both a comfortable ride and high grip. On this version, it has a three-way level control, selectable from the Multi Media Interface controls.

The steering system includes rack and pinion speed-dependent "servotronic" power steering, with a ratio of 12.5, and a turning circle of 12.2 metres.

The standard brakes on the RS 6 are cross-drilled, radially vented and floating iron discs. At the front they are 390 millimetres (15.35 in) diameter and 36 mm (1.417 in) thick, clamped by gloss black six-piston fixed Brembo monoblock alloy calipers incorporating the "RS" logo, and at the rear they are 356 mm (14.02 in) diameter and 28 mm (1.102 in) with black single-piston floating calipers and an integrated electro-mechanical parking brake linkage. The parking brake serves doubles as a full emergency brake whilst the car is in motion, by applying maximum braking effort to all four wheels, resulting in activating the Anti-lock Braking System (ABS).

Optional "Audi ceramic" Carbon fibre-reinforced Silicon Carbide (C/SiC) composite front brakes are available, only with 20-inch wheels, which use 420 mm (16.54 in) diameter by 40 mm (1.575 in) thick drilled, vented, and floating SGL Carbon composite discs, with grey painted eight-piston fixed Alcon monobloc alloy calipers with the "Audi ceramic" logo.

Irrespective of the type of disc construction, all brake discs are mounted via high strength steel mounting pins which connect the 'working' surface of the disc to lightweight alloy disc hubs.

A specifically 'tuned' "sport-biased" Bosch ESP 8.0 Electronic Stability Programme is standard, and includes Anti-lock Braking System (ABS) and Electronic Brakeforce Distribution (EBD), and Brake Assist (BA). This ESP system has three user-selectable settings: "ESP-on" - the standard default full protection mode, "ESP-sportmode" (which turns off the ASR and EDL traction functions), and "ESP-off" (which fully disables all 'stability' and 'traction' related functions).

Standard wheels (in the UK) are 9.5Jx20-inch '5-segment-spoke' design alloy wheels running on 275/35 ZR20 102Y XL (eXtra Load) tyres (rated at 850 kg (1,874 lb) per tyre), with official supplies being either Pirelli P-Zero Rosso or Dunlop SP SportMaxx GT. No-cost options are 9.5Jx20 '7-arm double spoke' design (identical style to B7 RS 4), or 9Jx19-inch '10-spoke' design alloys with 255/40 ZR19 Michelin Pilot Sport PS2 tyres.

• Digital Audio Broadcasting (DAB) digital radio tuner with DVD-based satellite navigation and Multi Media Interface (MMI), with optional hybrid digital/analogue TV tuner.
• Solar sunroof operating the air con whilst the vehicle is stationary and the engine is turned off
• Rear window and rear side window manual sun blinds

The RS6 Avant Performance is powered by the same 4.0-litre TFSI twin-turbo V8 engine as the standard RS6, [27] but with the help of a retuned ECU mapping, it increased power output to 605 PS (445 kW; 597 bhp) at 6100-6800 rpm and increased torque to 750 N⋅m (553 lbf⋅ft) at 2500-5500 rpm.[28] While the top speed remains limited to 250 km/h (155.3 mph), or 305 km/h (189.5 mph) with Dynamic Plus package, the 0 to 100 km/h (62.1 mph) time has been reduced to just 3.7 seconds at from 0 to 200 km/h (124.3 mph) in 12.1 seconds. Despite the improved performance, the fuel economy and CO₂ are unchanged from the standard RS6 Avant.