Modifying and improving: "M137 Modifications"

How to modify and upgrade the Mercedes M137

"Comprehensive guide to tuning and performance parts on the Mercedes M137 engine!"

TorqueCars are frequently getting posts requesting info on how to improve the M137 from people inquiring about getting more power from the M137 and wanting to know what are the ultimate M137 modifications. So let us look into Mercedes M137 upgrades and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

The Mercedes M137 make awesome project engines and with the ultimate tuning tuning mods like remapping, turbo upgrades and camshafts you will noticeably maximize your driving pleasure.

Car Tuning Tips will outline options for your M137 tuning and point out the ultimate mods that work.

Just because particular mods are popular with M137 owners it doesn't mean you should fit it, instead we'll focus on the optimum mods that will give your M137 the best power gain for you spend.

Without us subscribing to the popular mentality of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

Improving air intake on the M137

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 insufficient air it runs rich resulting in lost 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 the whole point to any engine upgrade task to force more air and fuel into the M137 engine but this has a knock on effect with the air flow sensor.

It is not unusual that there's a limit in the air flow sensor MAP/MAF/AFM on the M137 when loads 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 sapped bhp at a much lower level.

Intake take the during the engines suck phase from the air cleaner and allow it to be sucked into the engine cylinders.

The size of bore and shape and rate of flow of the Air Intake manifolds can make a large improvement to fuel atomisation on the M137.

Commonly we find the intake manifold are improved through performance upgrades, although a few car makers provide fairly well optimized intake manifold.

Fitting big valve kits, getting M137 port enlargement and head flowing will also lift performance, and importantly will give you raising the performance increase on other parts.

M137 performance cam tips.

Some M137 engines respond better to different cam durations than others.

The engine timing and fuelling also will say much on the power gains you'll make.

A longer valve duration can alter the power 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 M137 can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

NB: Fast road camshafts normally push up the power throughout the rev range, you may lose a little low end bhp but your higher rpm power will improve.

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

A Competition camshaft will just annoy you whilst on the daily commute.

You should ideally match your bhp range to your cars usage so for a car used daily stick with a mild fast road M137 camshaft

Stage 1, 2 and 3 mods for the M137

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 M137 parts:

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

Stage 2 M137 parts:

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

Stage 3 M137 parts:

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

Mapping helps to establish the full potential of all the upgrades you've done to your M137.

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 often differs on the upgrades you've applied and the condition of your engine.

Turbo modifications on the M137

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 M137.

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 is turbo charged mods are going to make more power and turbocharged engines already contain strengthened components.

However you will find an engines have limits

Research these restrictions and upgrade to better quality crank and pistons to handle the power.

It's not unheard of tuners spending a lot of money on turbocharger upgrades on the M137 only to have the whole thing literally blow up soon after it's first rolling road session.

Bigger capacity turbochargers tend to experience low end lag, and low capacity turbochargers spool up much more quickly but won't have the top end torque gains.

Thankfully the selection of turbo chargers is always evolving and we commonly find variable vane turbo chargers, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large torque gains, although more complex to setup. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the M137

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

More power needs more fuel. Most tuners we speak with say to be generous with your flow rate on the injectors.

The rule of thumb is to add 15% to the flow rate when buying an injector, this takes into account injector deterioration and allows a little 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 M137 performance exhaust upgrades

Only look to upgrade your exhaust system with an upgraded one is if your exhaust is creating a restriction.

On most factory exhausts you'll find your flow rate is 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.

Note that with the widest exhaust you can get this will reduce the exhaust flow rate - the best for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

Typically exhaust restrictions can be located the emissions filters installed, so adding a freer flowing high performance 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 M137

Like most engines an M137, 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 M137, failure to do this will exacerbate engine wear, on a tuned M137 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 M137 why not pop over to the forums at TorqueCars where you can chat about M137 tuning options and read about others projects who may be planning to do similar modifications on their M137.

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This entry was posted under Makes and Models. Tags: engine, mercedes
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