The Mercedes-Benz M256 engine is a turbocharged straight-six engine produced since 2017, when it was first introduced on the W222 S450.[1] It replaces the previous M276 V6 engine,[2] and is Mercedes' first straight-six engine since the M104 engine.[3]
Mercedes-Benz M256 | |
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Overview | |
Manufacturer | Mercedes-Benz |
Production | 2017–present |
Layout | |
Configuration | Straight-six engine |
Displacement | 3.0 L (2,999 cc) |
Cylinder bore | 83 mm (3.27 in) |
Piston stroke | 92.4 mm (3.64 in) |
Block material | Aluminium alloy |
Head material | Aluminium alloy |
Valvetrain | DOHC 4 valves x cyl. |
Compression ratio | 10.5:1 |
Combustion | |
Supercharger | BorgWarner's eBooster® Mitsubishi Crankshaft ISG system |
Turbocharger | Single-turbo twin-scroll |
Fuel system | Direct injection |
Fuel type | Petrol |
Cooling system | Water cooled |
Output | |
Power output | 270–320 kW (367–435 PS) |
Torque output | 500–520 N⋅m (369–384 lb⋅ft) |
Chronology | |
Predecessor | Mercedes-Benz M276 engine |
The M256 shares a modular design with other inline-four and V8 engines, which are all 500 cc (31 cu in) per cylinder.[4] It uses an aluminium alloy block with dual overhead camshafts and has 4 valves per cylinder.[5] The M256 uses a 48V electrical system to operate a BorgWarner electric supercharger,[6] which can spin up to 70,000 rpm to reduce turbo lag.[7] An integrated starter alternator also provides up to 16 kW (22 PS) and 250 N⋅m (184 lb⋅ft) of boost, and replaces the drive belts by managing the water pump and air conditioning; allowing for a smaller and lighter engine.[8]
Engine output excluding the additional 48V system boost:
Engine | Power | Torque | Years |
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M256 E30 DEH LA GR |
270 kW (367 PS; 362 hp) at 5,500–6,100 rpm |
500 N⋅m (369 lb⋅ft) at 1,600–4,000 rpm |
2017– |
M256 E30 DEH LA G |
320 kW (435 PS; 429 hp) at 5,900–6,100 rpm |
520 N⋅m (384 lb⋅ft) at 1,800–5,500 rpm |