Modding uprating the Mercedes M152 engine!

All you need to know about "M152 Modifications"

How to modify and upgrade the Mercedes M152

"Comprehensive guide to tuning and performance parts on the Mercedes M152 engine!"

Forums like the one at TorqueCars often are getting posts asking about how to improve the M152 from people inquiring about getting more power from the M152 and wanting to know what are the things tuners recommend when it comes to M152 mods that work. So let us look into Mercedes M152 upgrades and outline the best mods that work on this great engine and point out some common pitfalls along the way.

In this article we outline options for your M152 tuning and show the premier modifications. Mercedes M152 are popular engines and with a few sensible upgrades like remaps, turbo upgrades and camshafts you will definitely maximise your driving enjoyment.

The greatest M152 parts on an engine are sensibly the ones that give the best gains for your money.

We won't be swayed by popular M152 parts, they need to be cost effective.

M152 induction kits

Improving air intake on the M152

You need air and fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is not enough air it runs rich losing power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Forcing fuel and air into the M152 engine is the main goal to any engine upgrade project.

It is common that there's a limit in the air flow sensor (AFM/MAF/MAP) on the M152 when a lot more air is being sucked into the engine.

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

The intake plenum carry the on the suck phase from the air filter and allow it to be pulled into the engine cylinders.

Structure and flow characteristics of the air Intake manifold can make a noticeable change to fuel mixing and power on the M152.

It's not uncommon that plenum chambers are begging for aftermarket parts, although a few OEM provide reasonably well designed plenum chambers.

Larger M152 valves, getting port matching and head flowing will also lift torque, and more importantly will permit a better torque increase on other parts.

M152 performance cam tips.

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

The ECU mapping and injectors and fuel pump also will say much on the bhp gains you'll achieve.

Altering valve durations can alter the bhp 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.

Altering your M152 cam will make a dramatic difference to the engine engines power. Choosing a higher performance cam profile raises the engines power accordingly.

NB: Fast road cams tend to increase the bhp and torque throughout the rev band, you could sacrifice a little low down power but your high end rpm power will be lifted.

Race cams, increase the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race cam won't do well if driving in heavy traffic.

You should ideally match your torque band to your typical driving style so for a daily driver stick with a shorter duration M152 cam

Stage 1, 2 and 3 mods for the M152

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 M152 parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 2 M152 parts:

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

Stage 3 M152 parts:

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

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

Remaps helps to establish the full potential of all the parts you've done to your M152.

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage usually rely on the parts you've done and the condition of your engine.

Turbo modifications on the M152

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the M152.

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

If an engine has forced induction parts are giving better power gains and you'll see that turbo charged engines use many forged and stronger components.

However engines will need better parts at higher power limits

Discover these restrictions and install better quality components to cope with the power.

There are many tuners spending a lot of money on turbo upgrades on the M152 only to suffer the indignity of watching the M152 catastrophically fail soon after it's used in anger.

Big capacity turbos will usually experience no power at low rpm, and small turbos spool up quickly but don't have the top end torque gains.

Over the last 20 years the market of turbo chargers is always evolving and we are seeing variable vane turbo chargers, where the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo chargers divert the exhaust gases into 2 channels and flow these at differently angled vanes in the turbo. They also increase the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large power gains, although harder to setup. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the M152

You will need to ensure that the engine is not starved of fuel so need to ramp up the fuelling when you start going beyond 20% of a bhp hike. Experienced tuners recommend to over specify your injector capacity.

The rule of thumb is to add 20% when specifying an injector, this accounts for injector deterioration and provides you some spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended M152 performance exhaust upgrades

You only need to to upgrade your exhaust system with an upgraded one is if the existing exhaust is creating a restriction.

On most factory exhausts you'll see the flow rate is still ok even on modest power gains, but on a serious tuning project with a big boost in power you will certainly 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: it's over two and a half inches diameter, you will lose much of the exhaust flow rate and end up lacking power and torque.

Usual exhaust restrictions are traced to the catalyst and filters installed, so adding a freer flowing sports alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the M152

Like most engines an M152, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the M152, failure to do this will exacerbate engine wear, on a tuned M152 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your M152 why not pop over to the forums at TorqueCars where you can chat about M152 tuning options and read about others projects who may be planning to do similar modifications on their M152.

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