Modding tuning and best performance upgrades on the Mercedes OM656 engine!

Car tuning tips:OM656 Modifications"

OM656 Modifications Guide

How to modify and upgrade the Mercedes OM656

"Comprehensive guide to tuning the Mercedes OM656 engine!"

Our friends at TorqueCars often are getting messages about how to improve the OM656 from people inquiring about getting more power from the OM656 and wanting to know what are the best OM656 modifications. So let us look into Mercedes OM656 upgrades and outline the best mods that work on this great engine and point out some problems along the way.

Let us look into OM656 tuning and point out the best mods that work. Mercedes OM656 great bases for a tuning project and with carefully chosen uprated enhancements like a remap, turbo improvements and camshafts you will really enhance your driving pleasure.

The best OM656 mods on an engine are sensibly the ones that give the biggest return for your money.

We won't be swayed by popular OM656 mods, they need to be cost effective.

OM656 induction kits

Improving air intake on the OM656

You need air matched to fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is a lack of 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 it's important to any engine tuning job to push air into your OM656 but this has a knock on effect with the air flow sensor.

It is not unusual that there is a restriction in the air flow sensor AFM/MAP on the OM656 when considerably more air is being pulled into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp and torque at a much lower level.

Intake headers take the on the suck phase from the air filter and allow it to be sucked into the engine and mixed with fuel.

The shape and flow characteristics of the Air Intake manifolds can make a noticeable difference to to fuel mixing and power on the OM656.

It's not uncommon that intake are improved through aftermarket tuning parts, although a few makers provide reasonably good intake.

Larger OM656 valves, getting port work and head flowing will also raise bhp and torque, this will allow you to get a better bhp and torque increase on other modifications.

OM656 performance cam tips.

Some OM656 engines respond better to extreme camshaft durations so view each engine as unique.

The ecu map and injectors and fuel pump also will say much on the torque gains you'll get.

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.

Significant air intake, and exhaust improvements on the OM656 can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams commonly increase the bhp and torque through the rev range, you may sacrifice a little low end torque but the top end will be lifted.

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

A Motorsport camshaft makes it harder when driving around busy urban areas.

You should ideally optimize your torque band to your driving style so for a car driven daily stick with a shorter duration OM656 camshaft

Stage 1, 2 and 3 mods for the OM656

Stage 1 OM656 parts:

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

Stage 2 OM656 parts:

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

Stage 3 OM656 parts:

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

Plan your options and then find your tuning mods and set yourself a power target to avoid disappointment.

Mapping should help to release the full potential of all the tuning mods you've done to your OM656.

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

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 the end result may differs on the tuning mods you've fitted and the condition of your engine.

Turbo modifications on the OM656

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 OM656.

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.

If your motor is turbocharged, modifications are giving better power gains and you will discover turbocharged engines are made with stronger components.

However every engines have limits

See where you'll find these restrictions and upgrade to better quality components to handle the power.

We've seen people spending a loads on turbo charger upgrades on the OM656 only to suffer the humiliation of seeing the engine catastrophically fail when it's been enthusiastically driven.

Bigger capacity turbos commonly suffer no power at low rpm, and smaller turbos spool up more quickly but won't have the peak end engines power gains.

We are pleased that the selection of turbo chargers is always developing and we now see variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo chargers divert the exhaust flow into a couple of channels and feed these at differently profiled vanes in the turbocharger. 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 get working. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the OM656

Don't forget to look at the fuelling when you are increasing the performance - it makes the car more thirsty. We would recommend you to over specify your injector capacity.

As a rule of thumb add another 15% when specifying an injector, this accounts for injector deterioration and affords some spare capacity should the engine need 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 OM656 performance exhaust upgrades

You should look to increase your exhaust system with an upgraded one is if your exhaust is creating a restriction in flow.

On most factory exhausts you'll find the exhaust flow rate is still good 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 equal out the flow of gases through the engine.

But if the exhaust is too big, ie: over two and a half inches diameter, you will lose a great deal of the flow rate and end up losing power and torque.

Typically exhaust restrictions can be traced to the catalysts installed, so adding a freer flowing performance alternative will help avoid this restriction.

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

Faults issues and things to look out for on the OM656

Like most engines an OM656, 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 OM656, failure to do this will exacerbate engine wear, on a tuned OM656 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 OM656 why not pop over to the forums at TorqueCars where you can chat about OM656 tuning options and read about others projects who may be planning to do similar modifications on their OM656.

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