| Mercedes-Benz M256 | |
| Manufacturer: | Mercedes-Benz |
| Production: | 2017–present |
| Configuration: | Straight-six |
| Displacement: | 2498cc 2999cc |
| Bore: | 83 mm |
| Stroke: | 77 mm, 92.4 mm |
| Block: | Aluminium alloy |
| Head: | Aluminium alloy |
| Valvetrain: | DOHC 4 valves x cyl |
| Compression: | 10.5:1 |
| Supercharger: | BorgWarner eBooster |
| Turbocharger: | Single-turbo twin-scroll |
| Fuelsystem: | Direct injection |
| Fueltype: | Petrol |
| Coolingsystem: | Water cooled |
| Power: | NaN0NaN0 |
| Torque: | NaN0NaN0 |
| Predecessor: | Mercedes-Benz M276 |
The Mercedes-Benz M256 engine is a turbocharged straight-six engine produced since 2017, when it was first introduced on the W222 S 450.[1] It replaces the previous M276 V6 engine,[2] and is Mercedes' first straight-six engine since the M104 engine.[3]
The M256 shares a modular design with other inline-four and V8 engines, which are all 500cc 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] In the S 500's G variant engine, an integrated starter alternator also provides up to 160NaN0 and 2500NaN0 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 available on the S 500:[9]
| Engine | Power | Torque | Years |
|---|---|---|---|
| M256 E25 DEH LA GR | 2300NaN0 - 2700NaN0 at 5,500–6,100 rpm | 4500NaN0 at 1,600–4,000 rpm | 2021– |
| M256 E30 DEH LA GR | 2700NaN0 at 5,500–6,100 rpm | 5000NaN0 at 1,600–4,000 rpm | 2017– |
| M256 E30 DEH LA G | 3200NaN0 at 5,900–6,100 rpm | 5200NaN0 at 1,800–5,500 rpm |