Mercedes M157 Tuning

"All you need to know about tuning and performance parts on the Mercedes M157 engine!"

The Mercedes M157 are awesome to work on and with carefully chosen parts like a remap, turbo upgrades and camshafts you will maximize your driving enjoyment.

Here we detail the best approach to M157 tuning and highlight the optimum upgrades.

History, Power & Specs of the M157 Engine

M157

  •  544 PS 536 bhp at 5,500 rpm 800 Nm 590lbft at 2,000-4,500 rpm
  • 420 kW 571 PS 563 bhp at 5,500 rpm 900 Nm 664lbft (AMG pack)
  • 537 PS 530 bhp or 415 kW 564 PS 557 bhp
  • 525 PS 518 bhp 700 Nm 516lbft
  • 410 kW 557 PS 550 bhp 800 Nm 590lbft
  • 430 kW 585 PS 577 bhp 800 Nm 590lbft

The M157 was installed in the following models.

2011–2017 Mercedes-Benz S63 AMG
2011–2014 Mercedes-Benz CL63 AMG
2012–2018 Mercedes-Benz CLS 63 AMG
2012–2015 Mercedes-Benz ML 63 AMG
2015–2019 Mercedes-Benz AMG GLE 63
2012–2016 Mercedes-Benz GL 63 AMG
2016–2019 Mercedes-Benz AMG GLS 63
2013–2018 Mercedes-Benz G63 AMG
2012–2016 Mercedes-Benz E63 AMG
2012–2019 Mercedes-Benz SL63 AMG

Tuning the Mercedes M157 and best M157 performance parts.

Best M157 upgrades

When talking about the best modifications for your M157 engine, we are going to concentrate on the tuning parts that give the best power gain for you money.

The camshaft profile plays a big part in the engines power output so camshaft upgrades make quite a large difference. The intake & exhaust durations will alter depending on the chosen camshaft profile, so large engines power gains are on offer for camshaft upgrades.

Fast road cams usually boost the bhp and torque across the rev range, you may sacrifice a little low end torque but your top end will improve.

Motorsport and race cams, boost the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a car used daily you need to match your engines power to your usage of the car.

I'd be surprised if you have ever thought or claimed that a M157 Race camshaft is a pleasure to live with when driving in heavy traffic. The low end idle will be very lumpy and irregular, so something you would notice on a track when you drive in the upper third of the rpm band, but on roads this is a serious issue and we've heard from lots of drivers lamenting their decision to add an extreme competition cam profile to their engine.

Some M157 engines respond better to less aggressive cam durations than others.

The engine timing and fuelling also will make differences on the torque gains you'll achieve.

Altering valve durations can alter the torque band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

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Best Engine Mods for your car

  1. Mapping - remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.
  6. Typical stage 1 mods often include:
    Sports exhaust header/manifold, Remaps/piggy back ECU, drilled & smoothed airbox, Fast road camshaft, Intake manifolds, Panel air filters.

    Typical stage 2 mods often include:
    Fast road cam, Sports catalyst & performance exhaust, induction kit, fuel pump upgrades, high flow fuel injectors, Ported and polished head.

    Typical stage 3 mods often include:
    Engine balancing & blueprinting, Competition cam, Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions.

    The M157 units respond well to mods and thanks to their popularity there are increasing numbers of mods and tuning parts around.

    Mapping should help to fully realize the full potential of all the modifications you've done to your M157.

    (In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

    It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but power output usually differs on the modifications you've applied and the condition of your engine.

    Forcing more fuel and air into the M157 engine is vital to any engine upgrade task.

    Intake manifold carry the air from the filter and allow it to be sucked into the engine cylinders.

    Structure and rate of flow of the Intake can make a noticeable difference to fuel atomisation and engine efficiency on the M157.

    Many mass produced engine manifolds are improved through motorsport parts, although a few OEM provide fairly well optimized headers.

    Increasing the M157 valve size, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also boost performance, and importantly will give you a better performance increase on other tuning parts.

    M157 Turbo upgrades

    NA (naturally aspirated) engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your M157

    The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes impressive power gains.

    When your motor is turbo charged tuning parts are more reliable and turbo charged engines are made using stronger components.

    There are reliable limits for every engine, with some being extremely strong and some just sufficiently able to handle stock powerDiscover these limits and fit higher quality components to utilize the power.

    We see many car owners spending a lot of money on turbo charger upgrades on the M157 only to suffer the humiliation of seeing the motor throw a rod on it's first outing after it's finished.

    Large capacity turbo chargers commonly suffer low end lag, and little turbo chargers spool up more quickly but won't have the high rpm bhp gains.

    We are pleased that the selection of turbos is always developing and we are seeing variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

    Twin scroll turbos divert the exhaust flow into a couple of channels and direct these at differently angled vanes in the turbo. They also improve the scavenging effect of the engine.

    It is common that there's a limitation in the air flow sensor MAF/MAP on the M157 when loads more air is being sucked into the engine.

    Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped power at a much lower level.

    Adding a supercharger or additional turbo will make large torque gains, although more complex to get working. We have this guide to twinchargers if you want to read more.

    Fuelling

    Don't omit to boost the fuel delivery when you are increasing the bhp - it makes the car more thirsty. Don't forget to be generous with your injector capacity.

    The rule of thumb is to add another 20% when fitting an injector, this allows for injector deterioration and gives some spare capacity should the engine require more fuel.

    We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

    M157 Performance Exhausts

    Only look to upgrade your exhaust if your exhaust is actually causing a flow problem.

    On most factory exhausts you'll see the exhaust flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

    Don't go with the widest exhaust you can find you'll slow up the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

    Typically exhaust restrictions are traced to the filters installed, so adding a higher flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

    Weak spots, Issues & problem areas on the M157

    The M157 engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

    Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

    Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

    Regular oil changes are vital on the M157, especially when tuned and will help extend the life and reliability of the engine.

    If you would like to know more, or just get some friendly advice on Tuning your M157 engine please join us in our car forums where you can discuss M157 tuning options in more detail with our M157 owners. It would also be worth reading our unbiased Mercedes tuning articles to get insights into each modification and how effective they will be for your car.

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    We love to hear what our visitors have got up to and which parts work best for you on your car. Which helps us keep our guides and tips up to date helping others with their modified car projects. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these M157 tuning guides which get regular updates and revisions.

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