The Audi A8 L (D4, 4H facelift) 4.2 BiTDI V8 clean diesel, produced from 2013 to 2017, represents the pinnacle of diesel-powered luxury within the fourth generation of Audi’s flagship sedan. This long-wheelbase variant, designated internally as the D4/4H, received a significant facelift in 2013, bringing updated styling, enhanced technology, and refined powertrain options. The 4.2 BiTDI model, equipped with the eight-speed Tiptronic automatic transmission and Audi’s quattro all-wheel-drive system, was positioned as the performance-oriented diesel offering, sitting above the 3.0 TDI variants and below the petrol-powered 4.0 TFSI. It catered to buyers seeking a blend of effortless power, long-distance comfort, and relatively efficient operation.
Technical Specifications
| Brand | Audi |
| Model | A8 |
| Generation | A8L (D4,4H facelift 2013) |
| Type (Engine) | 4.2 BiTDI V8 clean diesel (385 Hp) quattro Tiptronic |
| Start of production | 2013 |
| End of production | 2017 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (economy) – urban | 9.5 l/100 km (24.8 US mpg, 29.7 UK mpg, 10.5 km/l) |
| Fuel consumption (economy) – extra urban | 6.2 l/100 km (37.9 US mpg, 45.6 UK mpg, 16.1 km/l) |
| Fuel consumption (economy) – combined | 7.5 l/100 km (31.4 US mpg, 37.7 UK mpg, 13.3 km/l) |
| CO2 emissions | 197 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 4.9 sec |
| Acceleration 0 – 62 mph | 4.9 sec |
| Acceleration 0 – 60 mph | 4.7 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 5.4 kg/Hp, 183.8 Hp/tonne |
| Weight-to-torque ratio | 2.5 kg/Nm, 405.7 Nm/tonne |
| Power | 385 Hp @ 3750 rpm |
| Power per litre | 93.1 Hp/l |
| Torque | 850 Nm @ 2000-2750 rpm (626.93 lb.-ft. @ 2000-2750 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | CTEC |
| Engine displacement | 4134 cm3 (252.27 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 83 mm (3.27 in.) |
| Piston Stroke | 95.5 mm (3.76 in.) |
| Compression ratio | 16.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 9.5 l (10.04 US qt | 8.36 UK qt) |
| Coolant | 12.2 l (12.89 US qt | 10.73 UK qt) |
| Kerb Weight | 2095 kg (4618.68 lbs.) |
| Max. weight | 2720 kg (5996.57 lbs.) |
| Max load | 625 kg (1377.89 lbs.) |
| Trunk (boot) space – minimum | 520 l (18.36 cu. ft.) |
| Fuel tank capacity | 82 l (21.66 US gal | 18.04 UK gal) |
| Max. roof load | 100 kg (220.46 lbs.) |
| Permitted trailer load with brakes (8%) | 2300 kg (5070.63 lbs.) |
| Permitted trailer load with brakes (12%) | 2300 kg (5070.63 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 95 kg (209.44 lbs.) |
| Length | 5265 mm (207.28 in.) |
| Width | 1949 mm (76.73 in.) |
| Width including mirrors | 2111 mm (83.11 in.) |
| Height | 1471 mm (57.91 in.) |
| Wheelbase | 3122 mm (122.91 in.) |
| Front track | 1644 mm (64.72 in.) |
| Rear (Back) track | 1635 mm (64.37 in.) |
| Front overhang | 1000 mm (39.37 in.) |
| Rear overhang | 1143 mm (45 in.) |
| Minimum turning circle (turning diameter) | 12.7 m (41.67 ft.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 8 gears, automatic transmission Tiptronic |
| Front suspension | Independent multi-link suspension |
| Rear suspension | Independent on trapezoidal lever |
| 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 | 235/55 R18 |
| Wheel rims size | 8J x 18 |
Powertrain & Engine Architecture
The heart of the A8 L 4.2 BiTDI is the CTEC engine, a 4.2-liter V8 diesel. This engine utilizes twin turbochargers, one for each bank of cylinders, along with intercooling to deliver substantial power and torque. The engine employs a common rail direct injection system, injecting fuel at extremely high pressures for optimized combustion. The valvetrain features four valves per cylinder, contributing to efficient gas exchange. The eight-speed Tiptronic automatic transmission, a staple of Audi’s high-performance models, provides smooth and responsive gear changes. The Tiptronic allows for both fully automatic operation and manual gear selection via steering wheel-mounted paddles or the gear selector. This transmission is designed to handle the engine’s significant torque output and contribute to both performance and fuel efficiency.
Driving Characteristics
The 4.2 BiTDI A8 L delivers a remarkably refined driving experience. The engine’s 850 Nm (626 lb-ft) of torque, available from a low 2000 rpm, provides effortless acceleration in virtually any situation. The 0-60 mph sprint takes approximately 4.7 seconds, making it genuinely quick for a large luxury sedan. The eight-speed Tiptronic transmission is well-matched to the engine, providing seamless shifts and keeping the engine in its optimal power band. Compared to the 3.0 TDI variants, the 4.2 BiTDI offers a significant performance advantage, with noticeably quicker acceleration and a more relaxed feel during highway cruising. While not as overtly sporty as the petrol-powered 4.0 TFSI, the 4.2 BiTDI provides a compelling balance of power and refinement.
Equipment & Trim Levels
The A8 L 4.2 BiTDI typically came generously equipped. Standard features included leather upholstery, heated and ventilated front seats with massage function, a premium sound system, a navigation system with MMI touch interface, adaptive air suspension, and a suite of driver-assistance systems such as adaptive cruise control, lane departure warning, and blind-spot monitoring. Optional extras included rear-seat entertainment, a panoramic sunroof, and various customization options for interior trim and exterior paint.
Chassis & Braking
The A8 L features an independent suspension system on all four wheels, utilizing multi-link setups for both the front and rear axles. The adaptive air suspension allows for adjustable ride height and damping settings, providing a comfortable ride while maintaining good handling characteristics. Braking duties are handled by ventilated discs on all four wheels, providing ample stopping power. The electronic stability control (ESC) system and anti-lock braking system (ABS) work in conjunction to enhance safety and stability.
Market Reception & Comparison
The A8 L 4.2 BiTDI was generally well-received by automotive critics. It was praised for its powerful engine, refined ride, luxurious interior, and advanced technology. Fuel economy, while not exceptional for a diesel, was considered respectable given the car’s size and performance. Compared to the 3.0 TDI models, the 4.2 BiTDI offered a significant performance upgrade, but at a higher price point. Reliability was generally good, although the complex diesel engine and associated technology could potentially lead to higher maintenance costs compared to simpler gasoline engines.
Legacy
The Audi A8 L 4.2 BiTDI (D4/4H) remains a desirable used luxury car. The CTEC engine, while complex, has proven to be relatively durable when properly maintained. However, potential buyers should be aware of the potential for costly repairs associated with the turbochargers, fuel injection system, and diesel particulate filter. The car’s advanced technology and luxurious features continue to appeal to buyers seeking a high-end, comfortable, and capable grand tourer. Its blend of performance, refinement, and efficiency has cemented its place as a notable offering in the luxury sedan segment.
