Tuning the Mercedes M137

"Comprehensive guide to tuning the Mercedes M137 engine!"

We often are getting posts inquiring about getting more power from the M137 and wanting to know what are the things we are recommending when it comes to M137 modifications. So let us look into Mercedes M137 mods and outline the best modifications on this great engine and point out some potential pitfalls along the way.

The Mercedes M137 offer good returns when tuned and with carefully picked performance parts like remapping, turbo improvements and camshafts you will positively improve your driving enjoyment.

Our aim here is to examine M137 tuning and summarise the premier modifications.

When talking about the best parts for your M137 engine, we are going to concentrate on the upgrades that give the best value for money.

Altering your M137 camshaft will make a dramatic difference to the engine power band. Choosing a higher performance camshaft profile raises the power band accordingly.

NB: Fast road camshafts tend to increase the bhp throughout the rev range, you might lose a little bottom end bhp but your top end will be lifted.

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

In a car driven daily one should, ideally, try to optimize your bhp range to your preferences.

I'd be gobsmaked if you have found a M137 Motorsport camshaft is a pleasure to live with when on the daily commute.

Each engine responds better to mild cam durations than others.

The engine timing and fuelling also have a large bearing on the torque gains you'll make.

Longer 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.

M137 Tuning Stages

Stage 1 M137 modifications: Sports exhaust manifold, Panel air filters, Remaps/piggy back ECU, Intake headers, Fast road camshaft, Drilled & smoothed airbox.

Stage 2 M137 modifications: fuel pump upgrades, high flow fuel injectors, induction kit, Fast road cam, Sports catalyst & performance exhaust, Ported and polished head.

Stage 3 M137 modifications: Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Competition cam.

ECU flashing allows a tuner to release the full potential of all the upgrades you've done to your M137.

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

Getting air into the M137 engine is vital to any car tuning job.

Intake headers take the air from the filter and allow it to be pulled into the engine and mixed with fuel.

Structure and flow characteristics of the Intake manifold can make a noticeable improvement to fuel atomisation and engine efficiency on the M137.

It's not uncommon that air intake manifolds are in dire need of motorsport parts, although a few manufacturers provide decently flowing air intake manifolds.

Larger M137 valves, doing some port work and head flowing will also lift bhp and torque, and significantly will give you a better bhp and torque increase on other modifications.

Turbo upgrades for the M137

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 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 significant power gains.

If your motor is fitted with a turbo tuning parts are relatively easy and most turbo charged engines are made using strengthened components.

There are tuning limits for every engine, with some being extremely strong and some only able to handle stock power

Discover these restrictions and install higher quality components to utilize the power.

We've seen mechanics spending a lot of money on turbo upgrades on the M137 only to see the M137 literally blow up on it's first outing after it's used on the roads.

Bigger turbos often experience low end lag, and low capacity turbos spool up quickly but do not have the high rpm engines power gains.

Thanks to new tech the selection of turbochargers is always improving and we now see variable vane turbochargers, where the vane angle is altered according to speed to lower lag and increase top end torque.

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

You'll commonly see there's a limitation in the air flow sensor MAF/MAP on the M137 when loads more air is being sucked into the engine.

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

Adding a supercharger or additional turbo will make large bhp and torque gains, although more difficult to get working. We have this guide to twinchargers if you want to read more.

Uprating M137 fuel injectors

Don't overlook the need to boost the fuel delivery when you are increasing the performance - it makes the car more thirsty. We strongly recommend you to over specify your flow rate on the injectors.

The accepted safe increase is to add another 20% when fitting an injector, helps cope with injector deterioration and gives a bit of 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 M137 performance exhausts

You may need to improve your exhaust if the current exhaust is creating a flow problem.

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

Note that with the biggest exhaust you can buy this will slow up 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.

Typically exhaust restrictions can be located the catalyst installed, so adding a faster flowing sports alternative will help avoid this restriction.

Problems and issues to look out for on the M137

The M137 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M137, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M137 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M137 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We really like hearing from our readers, and hearing about which upgrades were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our M137 guides and tips are kept up to date.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Mercedes. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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