Tuning the Mercedes M119

"Comprehensive guide to tuning the Mercedes M119 engine!"

We are frequently getting emails requesting info on the things we are recommending when it comes to M119 upgrades. So let us look into Mercedes M119 parts and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Mercedes M119 offer good returns when tuned and with carefully picked tuning mods like a remap, turbo improvements and camshafts you will substantially maximize your driving opportunities.

We shall review and look at M119 tuning and show the best modifications.

Just because particular upgrades are appear in lots of M119 projects it doesn't mean its worth having, so we'll optimum upgrades that will give your M119 the best power gain for you spend.

Altering your M119 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road camshafts commonly boost the bhp through the rev range, you could drop a little low down power but your top end will be lifted.

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

A Motorsport cam makes it harder when in heavy traffic.

You should ideally match your engines power to your cars usage so for a car driven daily stick with a shorter duration M119 cam

Different M119 engines respond better to extreme camshaft durations so set your engine up on a rolling road.

The ecu map and fuel pump and injectors 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.

M119 Tuning Stages

Stage 1 M119 modifications: Sports exhaust manifold, Drilled & smoothed airbox, Remaps/piggy back ECU, Fast road camshaft, Intake headers, Panel air filters.

Stage 2 M119 modifications: Ported and polished head, induction kit, Fast road cam, high flow fuel injectors, fuel pump upgrades, Sports catalyst & performance exhaust.

Stage 3 M119 modifications: Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Competition cam, Engine balancing & blueprinting, Crank and Piston upgrades to alter compression.

Carefully think through your options and then source your upgrades and set yourself a power target to avoid wasting your time and money.

Remaps will help fully realize the full potential of all the modifications you've done to your M119.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage will rely on the modifications you've fitted and the condition of your engine.

It is the whole point to any engine tuning project to pull more fuel and air into your M119

Intake flow the air during the suck phase from the air filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

The bore size, shape and flow characteristics of the Plenum can make a big effect on to fuel atomisation and engine efficiency on the M119.

I usually find headers are improved through aftermarket parts, although some manufacturers provide well optimised headers.

Increasing the M119 valve size, doing some 3 or 5 angle valve jobs and porting and head flowing will also improve bhp, and significantly will give you raising the bhp increase on other parts.

Turbo upgrades for the M119

NASP 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 M119

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

When your car is turbocharged, mods are relatively easy and you will discover turbo charged engines are built with uprated components.

There are weak spots for every engine, with some being extremely strong and some just sufficiently able to handle stock power

We recommend you find these limits and upgrade to better quality components to cope with the power.

We see many mechanics spending a lot of money on turbocharger upgrades on the M119 only to suffer the humiliation of seeing the motor explode soon after it's been enthusiastically driven.

Big capacity turbochargers tend to suffer no power at low rpm, and smaller turbochargers spool up more quickly but won't have the peak end bhp gains.

Over the last 20 years the world of turbos is always improving and we are seeing variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust flow into two channels and feed these at differently designed vanes in the turbo charger. They also help the scavenging effect of the engine.

You'll commonly see there is a limitation in the air flow sensor AFM/MAP on the M119 when a lot more air is being pulled into the engine.

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

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

Uprating M119 fuel injectors

When you improve the power you will need to increase to the fuel delivery.

More power needs more fuel. We would recommend you to over specify your injector capacity.

The rule of thumb is to add another 20% when buying an injector, this accounts for injector deterioration and allows a little spare capacity should the engine need 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.

Best M119 performance exhausts

You may need to replace your exhaust if the existing exhaust is actually creating a restriction in flow.

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

Please dont run with the biggest exhaust you can find this will reduce 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.

Common exhaust restrictions come around the filters installed, so adding a higher flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the M119

The M119 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M119, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M119 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M119 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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We really like hearing from our readers, and hearing about which tuning parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our M119 guides and tips are kept up to date.

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