The Audi S8 (D4 facelift) 4.0 TFSI COD V8, produced from 2013 to 2015, represents the pinnacle of performance and luxury within the D4 generation of Audi’s flagship sedan. This variant, equipped with a 4.0-liter twin-turbocharged V8 engine and an eight-speed Tiptronic automatic transmission, was positioned as the top-tier performance model, offering a significant step up from the standard A8 and even the more modestly powered S8 variants. It served as a direct competitor to high-performance luxury sedans from BMW and Mercedes-Benz, appealing to buyers seeking both exhilarating performance and sophisticated comfort. The “COD” designation refers to Cylinder On Demand, a fuel-saving technology that deactivates cylinders under light load.
Technical Specifications
| Brand | Audi |
| Model | S8 |
| Generation | S8 (D4 facelift 2013) |
| Type (Engine) | 4.0 TFSI COD V8 (520 Hp) quattro Tiptronic |
| Start of production | 2013 |
| End of production | 2015 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 13.6 l/100 km (17.3 US mpg, 20.8 UK mpg, 7.4 km/l) |
| Fuel consumption (extra urban) | 7.3 l/100 km (32.2 US mpg, 38.7 UK mpg, 13.7 km/l) |
| Fuel consumption (combined) | 9.6 l/100 km (24.5 US mpg, 29.4 UK mpg, 10.4 km/l) |
| CO2 emissions | 225 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.1 sec |
| Acceleration 0 – 62 mph | 4.1 sec |
| Acceleration 0 – 60 mph | 3.9 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 3.8 kg/Hp, 261.3 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 326.6 Nm/tonne |
| Power | 520 Hp @ 5800 rpm |
| Power per litre | 130.2 Hp/l |
| Torque | 650 Nm @ 1700-5500 rpm (479.42 lb.-ft. @ 1700-5500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | CTFA |
| Engine displacement | 3993 cm3 (243.67 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 84.5 mm (3.33 in.) |
| Piston Stroke | 89 mm (3.5 in.) |
| Compression ratio | 9.3:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 8.7 l (9.19 US qt | 7.65 UK qt) |
| Coolant | 14.8 l (15.64 US qt | 13.02 UK qt) |
| Kerb Weight | 1990 kg (4387.2 lbs.) |
| Max. weight | 2590 kg (5709.97 lbs.) |
| Max load | 600 kg (1322.77 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 | 5147 mm (202.64 in.) |
| Width | 1949 mm (76.73 in.) |
| Width including mirrors | 2111 mm (83.11 in.) |
| Height | 1458 mm (57.4 in.) |
| Wheelbase | 2994 mm (117.87 in.) |
| Front track | 1632 mm (64.25 in.) |
| Rear (Back) track | 1623 mm (63.9 in.) |
| Front overhang | 1012 mm (39.84 in.) |
| Rear overhang | 1141 mm (44.92 in.) |
| Drag coefficient (Cd) | 0.28 |
| Minimum turning circle (turning diameter) | 12.3 m (40.35 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 | 265/40 R20 |
| Wheel rims size | 9.0J x 20 |
Powertrain & Engine Architecture
The heart of the S8 (D4 facelift) 4.0 TFSI COD V8 is the CTFA engine, a 3,993 cc (243.67 cu. in.) twin-turbocharged V8. This engine utilizes direct fuel injection and a dual-scroll turbocharger configuration to deliver both high power and impressive torque. The Cylinder On Demand (COD) system is a key feature, allowing the engine to deactivate four cylinders (bank 1 or bank 2) during low-load cruising conditions, improving fuel efficiency without significantly impacting drivability. The engine’s valvetrain employs double overhead camshafts (DOHC) with four valves per cylinder. The eight-speed Tiptronic automatic transmission is specifically tuned for performance, offering quick and smooth gear changes. It features a torque converter lockup clutch that engages in most gears, further enhancing efficiency.
Driving Characteristics
The 520 hp and 650 Nm (479.42 lb-ft) of torque, combined with Audi’s quattro all-wheel-drive system, result in exhilarating acceleration. The 0-60 mph sprint is achieved in approximately 3.9 seconds, and the car is electronically limited to a top speed of 155 mph. The Tiptronic transmission provides responsive shifts, and the driver can manually select gears using the steering wheel-mounted paddles. Compared to the standard A8’s engines, the S8 offers a significantly more engaging driving experience. While not as raw or visceral as some rear-wheel-drive performance sedans, the S8 delivers a refined yet potent driving experience. The quattro system provides exceptional grip and stability in all weather conditions.
Equipment & Trim Levels
The S8 (D4 facelift) came standard with a comprehensive list of luxury and technology features. Interior appointments included Valcona leather upholstery, heated and ventilated front seats with massage function, a premium Bang & Olufsen sound system, and a power rear sunshade. Standard technology included Audi’s MMI navigation plus system with a touchscreen interface, adaptive cruise control, and a rearview camera. Optional extras included carbon fiber trim, a head-up display, and night vision assist. The S8 was positioned as the flagship trim, and therefore included nearly all available options as standard or readily available upgrades.
Chassis & Braking
The S8 features a sophisticated chassis designed to balance comfort and handling. It utilizes an adaptive air suspension system that allows the driver to adjust the ride height and damping characteristics. The suspension geometry is optimized for performance, and the car is equipped with a dynamic steering system that varies the steering ratio based on speed and driving conditions. Braking duties are handled by ventilated discs on all four wheels, with large calipers providing ample stopping power. The ABS (Anti-lock braking system) and electronic stability control systems are standard.
Market Reception & Comparison
The S8 (D4 facelift) 4.0 TFSI COD V8 was generally well-received by automotive critics. It was praised for its powerful engine, refined ride, and luxurious interior. The COD system was noted as a clever innovation that helped to improve fuel economy without sacrificing performance. Compared to its rivals, the S8 offered a unique blend of performance, luxury, and technology. Some critics noted that the steering feel was somewhat numb, and that the car lacked the outright sporting character of some rear-wheel-drive competitors. However, the S8’s all-weather capability and comfortable ride were considered significant advantages.
Legacy
The 4.0 TFSI engine, in various iterations, has become a mainstay in Audi’s performance lineup. The CTFA engine, while complex, has proven to be relatively reliable when properly maintained. Common issues include carbon buildup on the intake valves (a characteristic of direct-injection engines) and occasional turbocharger failures. In the used car market, the S8 (D4 facelift) 4.0 TFSI COD V8 remains a desirable option for buyers seeking a high-performance luxury sedan. Its combination of power, comfort, and technology continues to appeal to enthusiasts. Regular maintenance, including oil changes and inspections of the cooling system, is crucial to ensure the long-term reliability of this sophisticated powertrain.
