Mercedes M176/M177/M178: Everything You Need To Know

Considered the venerable M156, the Mercedes-AMG designed an engine range to fill the more oversized shoes left by the M157 and M278. The 4.0 Liter twin-turbo engine adapted some features and practices of its previous machines.

But what does this family can offer, and how do they differentiate from other Mercedes-AMG models?

Let’s find out about these details.

What are Mercedes M176/M177/M178 Engines?

The Mercedes-Benz M176/M177 or the high-performance M178 can be found in the majority of Mercedes-Benz vehicles such as the C-Class, S-Class, and other SUVs since 2015. This V8 bi-turbo engine, alongside the M156, is one of the first mass-produced machines with turbocharges mounted on the engine’s hot ‘V,’ where the intake and exhaust manifolds should be placed.

Placing the turbochargers on that spot allows the exhaust runners to travel shorter, resulting in a better turbocharger turbine spin since the temperature of exhaust gases remains.

The M176/M177/M178 engine replaced the Mercedes-Benz M157 and Mercedes-Benz M278; it is also badged as an AMG engine. Further engine developments include the ECO start/stop function, also equipped on other M engines.

This machine is a part of a modular engine family with the inline six-cylinder diesel, OM656; four-cylinder diesel engine, OM654; turbocharged inline six-cylinder gasoline engine, M256; and the turbocharged four-cylinder gasoline engine, M264.

The M176 engine is machine assembled with some components assembled by the technicians in Mercedes’ Untertürkheim plant. However, the M177 and M178 engines are made individually in the concept of “one man, one engine” at the AMG manufacturing center in Affalterbach.

Engine Specifications and Design:

  • Production Run: 2015 – Present
  • Cylinder Head Material: Aluminum
  • Cylinder Block Material: Cast-Aluminum
  • Configuration: V8
  • Bore: 83 mm
  • Stroke: 92 mm
  • Valvetrain: DOHC four valves per cylinder
  • Displacement: 4.0 L (3982 cc)
  • Compression Ratio: 10.5
  • Weight: 461 lbs.
  • Maximum HP: 641 HP at 6,250 RPM
  • Maximum Torque: 590 lb-ft at 2,000 – 6,000 RPM

There are three engines inside the M176/M177/M178 family; all of them are different on each of their own.

Let’s start with the Mercedes M176 version launched in 2015 for the Mercedes-Benz G 500/ G550 and G 500. The engine has a lightweight aluminum alloy cylinder block, in a closed-deck construction, produced through a permanent mold casting. The Mercedes M176 has an 83.0 mm cylinder bore, a 92 mm piston stroke, and a 10.5 compression rating.

Similar to its modular siblings, the cylinders have 90 mm space between each other. Within the cylinder bore surface is a twin-arc spraying tool to apply a low-friction coating called Nanoslide. This technology merges a mixture of metals to the walls, resulting in a much firmer surface that is twice as hard as a steel sleeve, as Mercedes claims it.

In addition to that, Nanoslide technology reduces the friction between the piston rings, piston, and cylinder wall by up to half and cuts the weight by at least several pounds.

The M176 engine underwent a honing process in which a plate resembling the cylinder heads is bolted onto the block to allow the mechanical surface treatment to proceed. The engine block honing simulates the stress akin to when the cylinder heads are already mounted. Which, in turn, reduces the tension of the piston rings and shrinks frictional losses and oil consumption.

The Mercedes M176 cylinder head is made from aluminum-zirconium alloy, a material with better heat conduction than the standard aluminum. It has two chain-driven overhead camshafts and four valves per cylinder.

The engine is also equipped with variable valve lift “Camtronic” to shut down the cylinders under low loads situations to increase the overall efficiency of the operational cylinders and reduce the pumping losses by shifting the operating directive towards higher loads.

The eight actuators act on the axially movable cam parts of both the intake and exhaust camshaft through a selector; this allows the accomplishment of a four-cylinder operation. The selection is only available in the comfort and efficiency modes. When the engine runs at engine speeds between 900 and 3,250, the cylinder shut-off becomes active.

The M176 engine has a centrifugal pendulum to prevent unnecessary vibrations in eight-cylinder mode and second-order vibrations in four-cylinder selection.

It is also installed with two exhaust gas-driven turbos mounted between the cylinder banks, and each of these turbochargers provides compressed air for one cylinder bank. Mercedes insulated the manifolds and exhaust turbochargers to protect peripheral components from intense heat.

The fuel delivery supply is through a piezo injector that sprays fuel at high pressure into the combustion chambers – in V8s; it’s eight. The direct injection is fully variable and electronically controlled, while the multiple injections happen on-demand for a more consistent air/fuel mixture.

The Mercedes M176, alongside the M256 engine, and according to Mercedes-Benz, they are the pioneers of large-scale use of particulate filter for gasoline engines; and later for M264 engines.

These filters have the same principles that those of diesel engines. The exhaust gas traverses a honeycomb-like particulate filter with alternately sealed inlet and outlet channels. With that, the exhaust gases have no option but to take the route of going through a porous filter wall trapping the soot. The filters can be continuously renewed under particular driving conditions.

Mercedes made the particulate gasoline filter from cordierite, a magnesium-aluminum-iron cyclosilicate, while the diesel engine uses ceramic filters made from carborundum (Silicon Carbide).

The M176 engine is equipped with an EQ Boost mild hybrid 48V system that allows the engine to produce higher output and torque. This system was installed to GLS 580 4MATIC and GLE 580 4MATIC. The engine was then upgraded with increased production of 496 HP.

Applications of Mercedes M176 Engine:

  • 2015 – 2018 Mercedes-Benz G 500/G 550
  • 2017 – 2020 Mercedes-Benz S 560/ S 560 4MATIC
  • 2017 – 2020 Mercedes-Maybach S 560/S 560 4MATIC
  • 2017 – 2020 Mercedes-Benz S560 Coupe and Cabrio
  • 2018 – Present Mercedes-Benz G 500/G 550 (second-generation)
  • 2019 – Present Mercedes-Benz GLE 580 4MATIC
  • 2019 – Present Mercedes-Benz GLS 580 4MATIC
  • 2021- Present Mercedes-Benz S 580 4MATIC
  • 2021 – Present Mercedes-Maybach S 580 4MATIC (without EQ Boost)

Mercedes M177

The M177 engine is the first variation released for the Mercedes C63. Compared to the M178 engine, M177 engines use wet-sump lubrication. The GLC63 and C63 applications have single-scroll turbos, whereas the E63 and S63 have different exhaust manifolds and twin-scrolled turbochargers. The twin-scroll applications feature cylinder deactivation.

In late 2019, Mercedes installed the 48V in the M177, similar to those of M176, for better performance, improved fuel consumption, and reduced emissions.

Applications of Mercedes M178 Engine:

  • 2015 – 2021 Mercedes-AMG C 65 and C 63 S
  • 2016 – Present Mercedes-AMG E63 4MATIC and E 63 S 4MATIC
  • 2017 – 2020 Mercedes-AMG S63 and S63 4MATIC
  • 2018 – Present Mercedes-AMG GT63 4MATIC, GT63 S 4MATIC, AND GT 73E Performance
  • 2019 Mercedes-AMG G63 second-generation
  • 2019 Mercedes-AMG GLC 63 4MATIC, GLC 63 4MATIC Coupe, GLC 63S 4MATIC Coupe
  • 2020 Mercedes-AMG GLE 63 4MATIC+ and 63S 4MATIC+
  • 2020 Mercedes-AMG GLS 63 4MATIC+
  • 2020 Mercedes-Maybach GLS 600 with ISG
  • 2020 Brabus Rocket 900
  • 2017 – Present Aston Martin DB11 V8 and DB11 Volante
  • 2018 – Present Aston Martin Vantage
  • 2021 – Aston Martin DBX

The Mercedes M178

This M178 engine is the second variation in the triumvirate family and leaning towards higher performance and motorsport. It uses dry-sump lubrication via a two-stage controlled suction pump, electronically controlled direct injection, and twin-scroll turbochargers for air delivery.

The 463 HP and 503 HP versions were initially used in Mercedes-AMG GT (C190). Mercedes upgraded the power output many times as well as for the motorsport. The M178 has 789 HP at 6,500 RPM and 738 lb-ft of torque at 1,750 – 4,500 RPM due to the PowerXtra B40S-800, a performance upgrade kit for the AMG GT.

Applications of Mercedes M178 Engine:

  • 2015 – Present Mercedes-AMG GT (C190) (Varying outputs, maximum at 523 HP at 6,750 RPM and 494 lb-ft of torque at 1,750 – 4,750 RPM)
  • 2015 – 2020 Mercedes-AMG GT S (C190) (515 HP at 6,250 RPM and 1,800 – 5,000 RPM)
  • 2017 – Present Mercedes GT C and GT R (577 HP at 6,250 RPM and 590 lb-ft of torque at 1,900 – 5,500 RPM)
  • 2020 – Present Mercedes-AMG GT Black Series (720 HP at 6,700 – 6,900 RPM and 590 lb-ft of torque at 2,000 – 6,000 RPM)
  • 2023 Aston Martin Valhalla (740 HP)

Engine Tuning, Upgrades, and Modifications:

The Mercedes M176/M177/M178 has a lot to offer and can be upgraded to achieve huge amounts of power and torque. You can do component replacements with the proper engine tuning that can boost the power at higher levels.

There are two stages for you to undertake. The first stage can reach 800 HP, while the second stage can increase your maximum power to 850-870 HP, depending on the upgrades.

For stage one, you can upgrade the turbochargers by reinforcing the housings. To proceed, you need a reinforced and a larger blade from solid compressor wheels, larger turbine wheels, CNC machined housings, an upgraded sleeve bearing system, and a VSR balance.

Stage 2 requires dual ceramic ball bearings, larger turbine wheels 55/49mm; 53/65 blades, refurbished housings, VSR balanced, and CNC-machined housings.

Problems Surrounding M176/M177/M178 Engine:

Considering the reliability of Mercedes engines, they are pretty formidable across the board. While these engines are a testament to long-lasting pieces of engineering, they still face issues, troubles, and weaknesses, knowing that there is no perfect engine.

In July 2019, the Mercedes Technical Service Bulletin issued a concern regarding random misfires among a specific cylinder. The bulletin also mentioned how to diagnose and document the case for warranty reimbursement.

On the same note, the bulletin laid out three fixes to alleviate and eliminate the misfires. The first is to check the coils, the second is to update the software in PTCU, VGS, and FSCU control units, and lastly, check the grounds for the ignition system. Some vehicles have their grounding stud painted.

Another issue is brass shaving in the filter, and this only applies to AMG-badged engines. The shavings are yellow paint applied to the connecting rod bolt, not brass.

Summary

The M176/M177/M178 bi-turbo V8s have been an integral part of the Mercedes engine progression. They are one of the first mass-produced V8s to have turbochargers and features to heighten its already yet high-performance rating. Fitted in any application but does not shy away from racing and motorsport.

The engine is lighter, more powerful, and advanced. Its future developments are much anticipated and have a lot of expectations to build up.

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