Tuning the Mercedes M270

"Comprehensive guide to tuning the Mercedes M270 engine!"

We are frequently seeing threads asking how to improve the M270 from people wanting to know what are the greatest M270 upgrades. So let us look into Mercedes M270 mods and outline the best mods that work on this great engine and point out some potential pitfalls along the way.

The Mercedes M270 really good project engines and with a few sensible modified upgrades like ECU maps, turbo improvements and camshafts you will really enhance your driving pleasure.

Let us review M270 tuning and point out the optimum mods that work.

Just because particular mods are appear in lots of M270 projects it doesn't mean you should fit it, instead we'll optimum mods that will give your M270 the best power gain for you money.

Significant gains on the M270 can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

NB: Fast road cams commonly push up the performance throughout the rev range, you could drop a little bottom end torque but higher rpm power will be better.

Competition cams, 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 Motorsport camshaft won't do well if driving in heavy traffic.

You should ideally optimize your bhp range to your driving style so for a car used daily stick with a mild fast road M270 camshaft

Different M270 engines respond better to more aggressive cam durations than others.

The map and injectors and fuel pump also have a large bearing 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.

M270 Tuning Stages

Stage 1 M270 modifications: Fast road camshaft, Sports exhaust manifold, Drilled & smoothed airbox, Remaps/piggy back ECU, Panel air filters, Intake headers.

Stage 2 M270 modifications: Sports catalyst & performance exhaust, Ported and polished head, induction kit, high flow fuel injectors, fuel pump upgrades, Fast road cam.

Stage 3 M270 modifications: Twin charging conversions, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting, Competition cam, Internal engine upgrades (head flowing porting/bigger valves).

ECU flashing helps unlock the full potential of all the tuning parts you've done to your M270.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the end result usually vary depending on the tuning parts you've carried out and the condition of your engine.

It is the whole point to any engine modification project to pull more air and fuel into the M270 engine

Headers transmit the air during the suck phase from the intake filter and allow it to be pulled into the engine and mixed with fuel.

The bore size, shape and flow characteristics of the Headers can make a big change to fuel atomisation and engine efficiency on the M270.

I usually find plenum chambers are begging for motorsport parts, although some OEM provide decently flowing plenum chambers.

Big valve conversions on the M270, doing some port work and head flowing will also boost bhp and torque, and as an added benefit will give you a better bhp and torque increase on other parts.

Turbo upgrades for the M270

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 M270

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.

If an engine has a turbo already fitted parts are going to make more power and you will discover turbo engines are made with uprated components.

However every engines have weakspots

Research these limitations and upgrade to better quality crank and pistons to utilize the power.

There are many drivers spending a a stack of money on turbocharger upgrades on the M270 only to suffer the indignity of watching the motor catastrophically fail just after it's been finished.

Bigger turbo units often experience a bottom end lag, and smaller turbo units spool up much more quickly but won't have the top end bhp gains.

Thanks to progress the selection of turbos is always moving on and we commonly find variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust gases into two channels and direct these at differently designed vanes in the turbocharger. They also increase the scavenging effect of the engine.

You'll commonly see there is a restriction in the air flow sensor AFM/MAF on the M270 when a lot more air is being sucked into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp at a much lower level.

Adding a supercharger or additional turbo will make large bhp gains, although more difficult to setup. We have this in depth look at twinchargers if you want to read more.

Uprating M270 fuel injectors

When you lift the power you will need to ramp up to the fuelling.

More power needs more fuel. It makes sense to be generous with your flow rate on the injectors.

The accepted safe increase is to add 20% capacity when specifying an injector, this accounts for injector deterioration and affords a little spare capacity should the engine require 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 M270 performance exhausts

You only need to to boost your exhaust if your exhaust is actually creating a flow problem.

On most factory exhausts you'll find your 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 slow the exhaust rate - the best exhausts 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 traced to the catalyst installed, so adding a higher flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the M270

The M270 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M270, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M270 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M270 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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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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