The Mercedes — Benz M 278.929 is a 5,980 cc, V8 twin — turbocharged petrol engine produced between 2011 and 2017. It features direct fuel injection (CGI), variable valve timing (VVT), and spray — guided combustion for enhanced performance. Delivering 386–430 kW (525–585 PS) and torque outputs of 800–900 Nm, it was engineered as the flagship high — performance petrol V8 for AMG — tuned applications.
Fitted to performance models including the S 63 AMG (W221/W222), CL 63 AMG (C…
Production years 2011–2013 meet Euro 5 standards; 2014–2017 models comply with Euro 6 depending on market (VCA UK Type Approval #VCA/EMS/6791).
The Mercedes-Benz M 278.929 is a 5,980 cc V8 twin-turbocharged petrol engine engineered for high-performance luxury applications (2011–2017). It combines direct fuel injection with twin-scroll turbochargers to deliver massive mid-range torque and rapid throttle response. Designed to meet Euro 5 and Euro 6 emissions standards, it balances AMG-level performance with improved fuel efficiency over its naturally aspirated predecessor.
| Parameter | Value | Source |
|---|---|---|
Displacement | 5,980 cc | |
Fuel type | Petrol | |
Configuration | V8, DOHC, 32-valve | |
Aspiration | Twin-turbocharged | |
Bore × stroke | 102.2 mm × 92.4 mm | |
Power output | 386–430 kW (525–585 PS) | |
Torque | 800–900 Nm @ 2,000–4,500 rpm | |
Fuel system | Direct injection (CGI), high-pressure fuel pump (up to 200 bar) | |
Emissions standard | Euro 5 (pre-2014); Euro 6 (2014–2017, market-dependent) | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Twin IHI turbochargers with twin-scroll design | |
Timing system | Chain-driven (dual, front-mounted) | |
Oil type | MB 229.51 (SAE 5W-30) | |
Dry weight | 225 kg |
The Mercedes-Benz M 278.929 was used across Mercedes-Benz's W221/W222/R231 platforms with longitudinal mounting and reserved for AMG performance variants. This engine received platform-specific adaptations-reinforced mounts in the S 63 AMG and revised exhaust routing in the SL 63 AMG-and from 2014 the introduction of revised camshaft profiles in the CL 63 S created interchange limits. All adaptations are documented in OEM technical bulletins.
The M 278.929's primary reliability risk is high-pressure fuel pump wear on early builds, with elevated incidence in high-mileage vehicles. Internal Mercedes-Benz quality reports from 2014 indicated a significant portion of pre-2014 engines required HPFP replacement before 120,000 km, while UK DVSA data shows petrol V8 engines account for a notable share of fuel system-related MOT advisories. Use of non-compliant fuel and extended oil intervals increase wear risk, making adherence to MB 229.51 specification and service schedules critical.
Analysis derived from Mercedes-Benz technical bulletins (2011-2017) and UK DVSA failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
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The M 278.929 offers exceptional performance and smooth power delivery, but early models (2011–2013) are prone to high-pressure fuel pump wear. Later units, especially post-2014 revisions, show improved durability when maintained properly. Regular oil changes with MB 229.51-specified 5W-30 oil every 15,000 km are essential. Well-maintained engines can exceed 180,000 km without major issues.
Key issues include high-pressure fuel pump wear (especially pre-2014), intake manifold flap actuator failure, coolant leaks from heater pipe O-rings, and ignition coil degradation. These are documented in Mercedes-Benz service bulletins. Carbon buildup in direct injection models and turbocharger wastegate sticking are less frequent but possible.
This V8 twin-turbo petrol engine was used in several AMG performance models: the W221/W222 S 63 AMG, C215/C216 CL 63 AMG, and R231 SL 63 AMG. It was phased out in 2018 and replaced by the M 178 V8. All variants are longitudinally mounted and paired with AMG SPEEDSHIFT MCT transmissions.
Yes, with moderate gains. ECU remapping can yield +50–90 kW on most variants due to headroom in turbo and fuel systems. However, the twin-turbo design limits extreme tuning compared to dedicated performance engines. Supporting modifications like intercooler upgrades and exhaust systems improve responsiveness. Over-tuning risks detonation, especially if fuel quality is poor.
Fuel consumption is typical for a high-performance twin-turbo V8. In a W222 S 63 AMG, expect ~16.5 L/100 km (city) and ~9.5 L/100 km (highway), or about 17 mpg UK combined. Real-world figures depend heavily on driving style, but 14–18 mpg (UK) is common. Use of RON 98 fuel is required for optimal performance and longevity.
Yes. The M 278.929 is an interference engine. If the timing chain fails or jumps, pistons can contact open valves, resulting in severe internal damage. While chain systems are generally robust, any signs of chain rattle or tensioner failure should be addressed immediately to prevent catastrophic engine failure.
Mercedes-Benz specifies SAE 5W-30 oil meeting MB 229.51 standard. This low-SAPS formulation is critical for protecting the high-pressure fuel pump and turbochargers. Oil must be changed every 15,000 km or annually. Using non-compliant oil increases wear and voids warranty on repairs.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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