Mercedes-Benz M278 engine

TheMercedes-BenzM278is a family ofdirect injected,Bi-turbocharged,V8gasolineautomotivepiston engines.

Mercedes-Benz M278/M157
Overview
Manufacturer	Mercedes-Benz Mercedes-AMG(AMG)
Production	2010–2020
Layout
Configuration	90°V8
Displacement	4.7 L; 284.6 cu in (4,663 cc) (M278) 5.5 L; 333.3 cu in (5,461 cc) (M157)
Cylinder bore	92.9 mm (3.66 in) 98 mm (3.86 in)
Piston stroke	86 mm (3.39 in) 90.5 mm (3.56 in)
Cylinder blockmaterial	Aluminium
Valvetrain	DOHC4 valvesx cyl. withVVT
Combustion
Turbocharger	HoneywellBi-turbos
Fuelsystem	Direct injection
Fuel type	Gasoline
Cooling system	Water-cooled
Output
Power output	300–430 kW (408–585 PS; 402–577 bhp)
Torque output	540–900 N⋅m (398–664 lb⋅ft)
Chronology
Predecessor	Mercedes-Benz M273 Mercedes-Benz M156
Successor	Mercedes-Benz M176/M177/M178

The M278 is derived from the company's previousM273V8 engine, sharing itsbore pitch,aluminiumengine block,and Silitec aluminium/silicon low-frictioncylinder liners.In contrast to the port-injected M273, the M278 featuresgasoline direct injection,withpiezo-electricallyactuated fuel injectors for more precise fuel delivery, and multi-spark ignition, which enables thespark plugsto be fired multiple times over the combustion sequence for more efficient combustion.Other changes relative to the M273 include an increased adjustment range for thevariable valve timingsystem, a new timing chain arrangement, and new engine accessories (such as the oil pump, water pump, fuel pump, and alternator) which reduceparasitic loads.Many of these new features are shared with theM276 V6 engine family,which was announced at the same time.

While the M273 wasnaturally aspirated,the M278 features twin turbochargers fromHoneywell,one per cylinder bank, producing 0.9 bar (13 psi) boost pressure in most configurations.

Mercedes-Benz estimated that these changes, with vehicle modifications such as astop-start system,give the 4.7–litre M278 22% lowerfuel consumptionandCO₂emissions than the 5.5–litre M273 while producing more power 320 kW (435 PS; 429 bhp) versus 285 kW (387 PS; 382 bhp) and torque 700 N⋅m (516 lb⋅ft) versus 530 N⋅m (391 lb⋅ft).

The entire M278 lineup avoids the United StatesGas Guzzler Tax,a first for V8 production engines from Mercedes-Benz.

M278

The basic M278 has a displacement of 4,663 cc (4.7 L; 284.6 cu in) with a bore and stroke of 92.9 mm × 86 mm (3.66 in × 3.39 in). Output is 320 kW (429 bhp; 435 PS) at 5,250 rpm with 700 N⋅m (516 lb⋅ft) of torque at 1,800-3,500 rpm for S-Class, CL-Class, SL-Class, and GL-Class models.CLS-Class, E-Class, and M-Class models are detuned to 300 kW (402 bhp; 408 PS) with 600 N⋅m (443 lb⋅ft) of torque at 1,600 rpm.Although it no longer corresponds with the engine displacement, all of the above models are still badged as "550". The GL-Class, besides the GL550 above, also features the GL450 trim that carries a detuned version of the 4.7 L engine making 270 kW (362 bhp; 367 PS) and 550 N⋅m (406 lb⋅ft)

For 2014 S-Class models (chassis code W222), power is increased to 335 kW (449 bhp; 455 PS) at 5,250 rpm, while torque remains at 700 N⋅m (516 lb⋅ft) between 1,800-3,500 rpm..

These engines are mated to the7G-Tronic7-speedautomatic transmission,and the new9G-Tronic9-speed automatic transmission.

Applications:

• 2011–2017S 500/S 550
• 2011–2014CL 500/CL 550
• 2015–2017S 500 Coupé/S 550 Coupé
• 2011–2018CLS 500/CLS 550
• 2012–2020SL 500/SL 550
• 2012–2014E 500/E 550
• 2012–2014ML 500/ML 550
• 2013–2014GL 450
• 2013–2019GL 500/GLS 500/GL 550/GLS 550

M157 AMG

The second variant, designatedM157,is tuned byMercedes-AMGfor use in higher-performance models. This version has a displacement of 5,461 cc (5.5 L) with a bore and stroke of 98 mm × 90.5 mm (3.86 in × 3.56 in).Increased power and torque comes from the increased displacement as well as higher boost pressure of 1 bar (15 psi).

There are six states of output with the M157. For the S-Class and CL-Class, power is 400 kW (544 PS; 536 bhp) at 5,500 rpm with 800 N⋅m (590 lb⋅ft) of torque at 2,000-4,500 rpm, or 420 kW (571 PS; 563 bhp) at 5,500 rpm with 900 N⋅m (664 lb⋅ft) of torque at 2,500-3,750 rpm with the optional AMG Performance Package.For the 2013-15 SL-Class, power is 395 kW (537 PS; 530 bhp) or 415 kW (564 PS; 557 bhp) with the optional AMG Performance Package. For the 2012-2013 E-Class and CLS-Class, power is 386 kW (525 PS; 518 bhp) with 700 N⋅m (516 lb⋅ft) of torque in standard tune, or 410 kW (557 PS; 550 bhp) with 800 N⋅m (590 lb⋅ft) of torque with the AMG Performance Package.Beginning with the 2014 E-Class and CLS-Class, power increases to 410 kW (557 PS; 550 bhp) 720 N⋅m (531 lb⋅ft) of torque for standard tune, or 430 kW (585 PS; 577 bhp) with 800 N⋅m (590 lb⋅ft) of torque for "S-Model" variants.At the same time for SL-Class, power increases to 430 kW (585 PS; 577 bhp) and 900 N⋅m (664 lb⋅ft).

These engines are mated to theAMG Speedshift MCT 7-speedsemi-automatic transmission,which replaces the 7G-Tronic'storque converterwith awet clutchpack.Note that this MCT 7-speed can handle considerably more torque and is not the same unit as thedual-clutch transmissionfound on theMercedes-Benz SLS AMG.

Applications:

• 2011–2013S 63 AMG
• 2013–2017S 63 AMG
• 2011–2014CL 63 AMG
• 2012–2018CLS 63 AMG
• 2012–2015ML 63 AMG
• 2015–2019AMG GLE 63
• 2012–2016GL 63 AMG
• 2016–2019AMG GLS 63
• 2013–2018G 63 AMG
• 2012–2016E 63 AMG
• 2012–2019SL 63 AMG

The M157 engine will replace the previous M156 in most of the AMG lineup. Despite the 5.5–litre displacement, all models are designated "63" for marketing purposes.

M152

Main article:Mercedes-Benz M152 engine

The third variant, designatedM152,is anaturally aspiratedderivative of the M157 engine, sharing the same displacement, direct injection, and many other features. The M152 engine includes a cylinder deactivationvariable displacementsystem for improvedfuel economy(up to 30 percent better than theM113 E55engine used in the previous model). Output is 310 kW (421 PS; 416 bhp) at 6,800 rpm, with 540 N⋅m (398 lb⋅ft) of torque at 4,500 rpm.

Applications

• 2012–2016SLK 55 AMG (R172)