Mercedes M275 Tuning

"All you need to know about performance parts and tuning the Mercedes M275 engine!"

Herein we consider M275 tuning and provide tips on the ultimate modifications for your car. Mercedes M275 really good project engines and with the best tuning modifications like ECU maps, turbo improvements and camshafts you will greatly maximise your driving experience.

History, Power & Specs of the M275 Engine


  •  500 PS 493 hp to 380 kW 517 PS 510 hp at 5000 rpm and 800 Nm 590lbft to 830 Nm 612lbft at 1800–3500 rpm.
  •  500 PS 493 hp to 380 kW 517 PS 510 hp at 5000 rpm and 800 Nm 590lbft to 830 Nm 612lbft at 1800–3500 rpm.


  • 2003–2013 S600
  • 2003–2014 CL600
  • 2003–2011 SL600

M275 AMG

  • 612 PS 603 hp at 4800–5100 rpm 1,000 Nm 738lbft at 2000–4000 rpm
  • 2004–2013 S65 AMG
  • 2004–2014 CL65 AMG
  • 2004–2011 SL65 AMG
  • 2012-2015 G65 AMG
  • 2005–2012 Maybach 57 and 62 "S" trims.

Tuning the Mercedes M275 and best M275 performance parts.

Best M275 mods

When talking about the best modifications for your M275 engine, we are going to focus on the upgrades that give the best value for money.

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

Fast road camshafts usually push up the power across the rev band, you could sacrifice a little low down bhp but your top end will be higher.

Motorsport camshafts, push up the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a road car you need to optimize your bhp range to your typical driving style.

I'd be surprised if you have ever thought or claimed that a M275 Motorsport cam is a pleasure to live with when driving around busy urban areas. This is because a competition cam causes a very lumpy idle, and makes the car more prone to stall or jerk along in stop start traffic, sadly though many ignore this and end up ruining a perfectly good car and having to revert back to a fast road, or OEM cam profile.

Each engine responds better to more aggressive camshaft durations so set your engine up on a rolling road.

The map and fuelling also have an effect on the torque gains you'll get.

A longer valve duration 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.

Please watch our video which covers the 5 principles of tuning your car. Be sure to keep up with our latest YouTube content and subscribe.

Best Engine Mods for your car

  1. Engine Tunes - engine tuning/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, Intake manifolds, Fast road camshaft, Panel air filters, drilled & smoothed airbox, Remaps/piggy back ECU.

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

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

    Review your options and then acquire your tuning parts and set yourself a power target to avoid disappointment.

    Mapping will help fully realize the full potential of all the tuning mods you've done to your M275.

    (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 your mileage usually vary depending on the tuning mods you've done and the condition of your engine.

    It is the main goal to any performance tuning task to get air and fuel into the M275 engine

    Intake manifold transmit the air from the filter and allow it to be fed into the engine cylinders with fuel for the squish phase.

    Structure and flow rate of the Intake manifold can make a large effect on to fuel atomisation and engine efficiency on the M275.

    Commonly we find the intake manifold are in dire need of performance upgrades, although a few makers provide decently flowing intake manifold.

    Larger M275 valves, doing some M275 port enlargement and head flowing will also lift bhp, & importantly will make space for increasing the bhp increase on other upgrades.

    M275 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 M275

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

    When an engine has a turbo already fitted upgrades are relatively easy and you'll see that turbocharged engines already contain many forged and stronger components.

    However most engines will have power limits.It is important to find these restrictions and install forged components to handle the power.

    We've seen mechanics spending a lots of money on turbocharger upgrades on the M275 only to experience the whole thing catastrophically fail just after it's been enthusiastically driven.

    Larger turbo units will usually suffer no power at low rpm, and smaller turbo units spool up much more quickly but won't have the top end torque gains.

    Thankfully the selection of turbochargers is always increasing and we now see variable vane turbochargers, where the vane profile is altered according to speed to lower lag and increase top end bhp.

    Twin scroll turbochargers divert the exhaust flow into a couple of channels and direct these at differently profiled vanes in the turbo charger. They also increase the scavenging effect of the engine.

    It is common that there's a restriction in the air flow sensor (AFM/MAF/MAP) on the M275 when loads more air is being fed into the engine.

    We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited bhp and torque at a much lower level.

    Adding a supercharger or additional turbo will make large performance gains, although more challenging to install. We have this article on twincharging if you want to read more.


    When you raise the bhp and torque you will need to pay attention to the fuelling.

    More bhp and torque needs more fuel. It is important to over specify your injectors flow rate.

    The accepted safe increase is to add another 20% when specifying an injector, this accounts for injector deterioration and provides you 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.

    M275 Performance Exhausts

    You only need to uprate your exhaust if your current exhaust is actually causing a restriction.

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

    Sports exhausts balance the flow of air through the engine.

    But if your exhaust pipe is too large, ie: over 2.5 inches bore, you will lose much of the flow rate and end up losing power and torque.

    Common exhaust restrictions can be traced to the catalysts installed, so adding a better flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

    Weak spots, Issues & problem areas on the M275

    The M275 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 M275, 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 M275 engine please join us in our car forums where you can discuss M275 tuning options in more detail with our M275 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 upgrades 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 M275 tuning guides which get regular updates and revisions.

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