The Audi A6 Sedan (C8) 40 TDI quattro ultra S tronic represents a significant iteration in Audi’s long-running A6 lineage. Introduced in 2018 and continuing through a May 2023 production run, this variant occupied a crucial position within the C8 generation, offering a blend of efficiency, performance, and technology aimed at the executive sedan market. It served as a key diesel offering in Europe and other markets where diesel fuel remained popular, providing a compelling alternative to gasoline-powered A6 models and acting as a stepping stone to the more powerful TDI variants.
Technical Specifications
| Brand | Audi |
| Model | A6 |
| Generation | A6 Sedan (C8) |
| Type (Engine) | 40 TDI (204 Hp) quattro ultra S tronic |
| Start of production | 2018 |
| End of production | May, 2023 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Combined fuel consumption (WLTP) | 5.9-6.2 l/100 km (39.9 – 37.9 US mpg, 47.9 – 45.6 UK mpg, 16.9 – 16.1 km/l) |
| CO2 emissions (WLTP) | 155-165 g/km |
| Fuel consumption (urban) | 4.8-4.9 l/100 km (49 – 48 US mpg, 58.9 – 57.6 UK mpg, 20.8 – 20.4 km/l) |
| Fuel consumption (extra urban) | 4.1-4.4 l/100 km (57.4 – 53.5 US mpg, 68.9 – 64.2 UK mpg, 24.4 – 22.7 km/l) |
| Fuel consumption (combined) | 4.3-4.6 l/100 km (54.7 – 51.1 US mpg, 65.7 – 61.4 UK mpg, 23.3 – 21.7 km/l) |
| CO2 emissions | 114-120 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.6 sec |
| Acceleration 0 – 62 mph | 7.6 sec |
| Acceleration 0 – 60 mph | 7.2 sec |
| Maximum speed | 246 km/h (152.86 mph) |
| Emission standard | Euro 6d – TEMP |
| Weight-to-power ratio | 8.4 kg/Hp, 119.6 Hp/tonne |
| Weight-to-torque ratio | 4.3 kg/Nm, 234.6 Nm/tonne |
| Power | 204 Hp @ 3750-4200 rpm |
| Torque | 400 Nm @ 1750-3000 rpm (295.02 lb.-ft. @ 1750-3000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | DFBA |
| Engine displacement | 1968 cm3 (120.09 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Coolant | 10.8 l (11.41 US qt | 9.5 UK qt) |
| Kerb Weight | 1705 kg (3758.88 lbs.) |
| Max. weight | 2325 kg (5125.75 lbs.) |
| Max load | 620 kg (1366.87 lbs.) |
| Trunk (boot) space – minimum | 530 l (18.72 cu. ft.) |
| Fuel tank capacity | 63 l (16.64 US gal | 13.86 UK gal) |
| Max. roof load | 90 kg (198.42 lbs.) |
| Permitted trailer load with brakes (8%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load with brakes (12%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 95 kg (209.44 lbs.) |
| Length | 4939 mm (194.45 in.) |
| Width | 1886 mm (74.25 in.) |
| Width including mirrors | 2110 mm (83.07 in.) |
| Height | 1457 mm (57.36 in.) |
| Wheelbase | 2924 mm (115.12 in.) |
| Front track | 1630 mm (64.17 in.) |
| Rear track | 1617 mm (63.66 in.) |
| Front overhang | 920 mm (36.22 in.) |
| Rear overhang | 1095 mm (43.11 in.) |
| Drag coefficient (Cd) | 0.27 |
| Minimum turning circle | 12.1 m (39.7 ft.) |
| Drivetrain Architecture | All wheel drive (4×4). ICE drives front wheels, rear driven by clutch. |
| Drive wheel | All wheel drive (4×4) |
| Number of gears | 7 |
| Gearbox type | Automatic transmission S tronic |
| Front suspension | Independent multi-link suspension |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 225/60 R17 |
| Wheel rims size | 7.5 J x 17 |
INTRODUCTION
The Audi A6 Sedan (C8) 40 TDI quattro ultra S tronic, launched in 2018, is a four-door, five-seater executive car that forms part of the eighth generation of the A6. Positioned as a mid-range offering within the C8 lineup, it aimed to provide a balance between fuel efficiency, respectable performance, and the luxury features expected of an Audi. The “40 TDI” designation indicates the engine’s power output relative to Audi’s internal naming convention, while “quattro ultra” signifies the on-demand all-wheel-drive system, and “S tronic” denotes the seven-speed dual-clutch transmission. This model was particularly popular in European markets and regions with favorable diesel policies.
Powertrain & Engine Architecture
At the heart of the A6 40 TDI lies the DFBA engine, a 2.0-liter inline-four cylinder diesel engine. This engine is a member of the Volkswagen Group’s modular engine family, known for its compact dimensions and efficiency. It utilizes a common-rail direct fuel injection system, delivering fuel at extremely high pressure for optimized combustion. The engine is turbocharged with a single turbocharger and intercooled, boosting power and torque. The engine produces 204 horsepower at 3750-4200 rpm and 400 Nm (295 lb-ft) of torque between 1750 and 3000 rpm. The S tronic seven-speed dual-clutch transmission provides rapid and smooth gear changes. Unlike a traditional automatic, the S tronic pre-selects the next gear, minimizing interruption in power delivery. The quattro ultra system intelligently distributes torque between the front and rear axles as needed, enhancing traction and stability. In normal driving conditions, the system primarily operates in front-wheel drive to maximize fuel economy, engaging the rear axle only when slip is detected or during more demanding driving scenarios.
Driving Characteristics
The A6 40 TDI S tronic offers a refined and comfortable driving experience. While not overtly sporty, the 204 hp engine and the quick-shifting S tronic transmission provide adequate acceleration, achieving 0-60 mph in approximately 7.2 seconds. The engine delivers strong low-end torque, making it well-suited for everyday driving and overtaking maneuvers. The seven-speed transmission is well-tuned, offering smooth and responsive shifts. The quattro ultra all-wheel-drive system provides enhanced grip and stability, particularly in adverse weather conditions. Compared to the more powerful TDI variants (like the 50 TDI), the 40 TDI feels less urgent in its acceleration, but it compensates with improved fuel economy. The automatic transmission, while efficient, may not offer the same level of driver engagement as a manual gearbox.
Equipment & Trim Levels
The A6 40 TDI quattro ultra S tronic typically came well-equipped, reflecting its position as a premium executive sedan. Standard features often included Audi’s MMI touch response infotainment system with dual touchscreens, leather upholstery, three-zone automatic climate control, and a suite of driver-assistance systems such as lane departure warning and automatic emergency braking. Optional extras included features like a Bang & Olufsen sound system, a head-up display, adaptive cruise control, and matrix LED headlights. Trim levels varied by market, but generally offered increasing levels of luxury and technology. The base trim provided a comfortable and well-equipped experience, while higher trims added more premium materials and advanced features.
Chassis & Braking
The C8 A6 utilizes a sophisticated chassis design featuring independent multi-link suspension at both the front and rear axles. This setup provides a comfortable ride quality while maintaining good handling characteristics. The suspension is tuned to prioritize comfort, but it remains composed and controlled during cornering. The A6 40 TDI is equipped with ventilated disc brakes on all four wheels, providing ample stopping power. Anti-lock braking system (ABS) and electronic stability control (ESC) are standard features, enhancing safety and control. The steering is electrically assisted, offering precise and responsive steering feel.
Market Reception & Comparison
The A6 40 TDI quattro ultra S tronic was generally well-received by automotive critics. It was praised for its refined driving experience, comfortable interior, and fuel efficiency. Critics noted that while the engine wasn’t the most powerful in the A6 lineup, it provided a good balance of performance and economy. Compared to the higher-output TDI variants, the 40 TDI offered lower running costs and a more accessible price point. Against competitors like the BMW 5 Series and Mercedes-Benz E-Class, the A6 40 TDI was seen as a strong contender, offering a compelling combination of luxury, technology, and efficiency. Fuel economy figures consistently hovered around 5.9-6.2 l/100km, making it an attractive option for drivers covering long distances.
Legacy
The DFBA engine and S tronic transmission pairing in the A6 40 TDI have proven to be relatively reliable. While diesel engines can be susceptible to issues with the diesel particulate filter (DPF) if not driven on longer journeys, the DFBA engine has generally demonstrated good durability. The S tronic transmission, while complex, has also proven to be robust when properly maintained. On the used car market, the A6 40 TDI quattro ultra S tronic remains a popular choice, offering a well-rounded package at a competitive price. Its fuel efficiency and comfortable ride continue to appeal to buyers seeking a refined and practical executive sedan.
