Mercedes-Benz M256
Overview
ManufacturerMercedes-Benz
Production2017–present
Layout
ConfigurationStraight-six
Displacement2.5 L (2,498 cc)
3.0 L (2,999 cc)
Cylinder bore83 mm (3.27 in)
Piston stroke92.4 mm (3.64 in)
Cylinder block materialAluminium alloy
Cylinder head materialAluminium alloy
ValvetrainDOHC 4 valves x cyl.
Compression ratio10.5:1
Combustion
SuperchargerBorgWarner's eBooster®
Mitsubishi Crankshaft ISG system
TurbochargerSingle-turbo twin-scroll
Fuel systemDirect injection
Fuel typePetrol
Cooling systemWater cooled
Output
Power output270–320 kW (367–435 PS)
Torque output500–520 N⋅m (369–384 lb⋅ft)
Chronology
PredecessorMercedes-Benz M276

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]

Design

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] In the S500's G variant engine, 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]

Models

Engine output excluding the additional 48V system boost available on the S500:[9]

Engine Power Torque Years
M256 E25
DEH LA GR 		230 kW (313 PS; 308 hp) - 270 kW (367 PS; 362 hp)
at 5,500–6,100 rpm 		450 N⋅m (332 lb⋅ft)
at 1,600–4,000 rpm 		2021–
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

M256 E25 DEH LA GR

M256 E30 DEH LA GR

M256 E30 DEH LA G

References

  1. ^ "2018 Mercedes-Benz S500 European-Spec First Drive: Ice, Ice Baby. Too Cool, Too Cool". MotorTrend. 19 July 2017. Retrieved 2018-07-03.
  2. ^ "Mercedes To Phase Out V6 Engines In Favor Of Straight-Sixes". Motor1.com. Retrieved 2018-07-03.
  3. ^ "Mercedes-Benz M256 inline 6-cylinder gasoline engine - MarkLines Automotive Industry Portal".
  4. ^ "Why Mercedes' new inline six matters, even if no one is sure when we'll see it". Autoweek. Retrieved 2018-07-03.
  5. ^ "First Drive: 2018 Mercedes-Benz S-Class | Automobile Magazine". Automobile Magazine. 2017-07-18. Retrieved 2018-07-03.
  6. ^ "This Little Fan Could Fix the Turbocharger's Biggest Problem—And Make Cars Way More Efficient". WIRED. Retrieved 2018-07-03.
  7. ^ "Nine Things You Must Know about the New Mercedes Inline-Six". Car and Driver. Retrieved 2018-07-03.
  8. ^ "Why Mercedes-Benz Is Going All In on Straight-Sixes". Road & Track. 2016-11-01. Retrieved 2018-07-03.
  9. ^ Kuruvilla, George. "Everything you need to know about the all-new 2021 Mercedes-Benz S-Class". Khaleej Times. Retrieved 2022-12-18.
  10. ^ "2018 Mercedes-Benz S 450". Car and Driver. Retrieved 2018-07-03.
  11. ^ Kable, Greg (2017-11-19). "2018 Mercedes-Benz CLS review - Mercedes-Benz's new CLS from the passenger seat". Drive. Retrieved 2018-07-03.
  12. ^ Panait, Mircea (2017-09-16). "Aston Martin Straight-6 Engine Could Come Back Thanks To Mercedes-Benz". autoevolution. Retrieved 2018-07-03.
  13. ^ "The 2019 Mercedes CLS53 and E53 Bring Straight-Sixes Back to AMG". Road & Track. 2018-01-15. Retrieved 2018-07-03.
  14. ^ "Hot Hybrids: Mercedes Launches Electrified AMG 53 Range". Motor1.com. Retrieved 2018-07-03.
  15. ^ "630bhp Mercedes-AMG GT 4-door Coupé: Edition 1 version confirmed | Autocar". www.autocar.co.uk. Retrieved 2018-07-03.

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