Tuning the Mercedes M271

"Comprehensive guide to performance tuning the Mercedes M271 engine!"

We are frequently getting posts asking how to improve the M271 from people wanting to know what are the ultimate M271 power upgrades. So let us look into Mercedes M271 parts and outline the best modifications on this great engine and point out some problems along the way.

The Mercedes M271 offer good returns when tuned and with the ultimate tuning upgrades like a remap, turbo kits and camshafts you will increase your driving experience.

Our aim here is to look at M271 tuning and summarise the optimum modifications for your car.

Just because particular parts are popular with M271 owners it doesn't mean it is good, instead we'll best parts that will give your M271 the best power gain for you spend.

Altering your M271 camshaft will make a dramatic difference to the engine torque. Choosing a higher performance camshaft profile raises the torque accordingly.

NB: Fast road cams commonly raise the bhp and torque through the rpm range, you may lose a little low down bhp but higher rpm power will be better.

Competition cams, raise the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport and race camshaft makes it harder when driving in heavy traffic.

You should ideally match your engines power to your cars usage so for a daily driver stick with a shorter duration M271 camshaft

Some M271 engines respond better to more aggressive cam durations than others.

The engine timing and injectors and fuel pump also will make differences on the torque gains you'll make.

Extending exhaust or intake 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.

Best M271 Tuning Mods & Upgrades

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Guide to the best M271 tuning mods & Upgrades

  1. ECU Map Tuning & Remaps

    Some cars may require a piggyback ECU's or aftermarket ECU's to change the OEM map, but remapping is the most vital step of your tuning project to fully maximise your mods. Expect 10-20% on NASP engines and 30-40% on turbocharged units.

  2. Strengthen Your Engine

    Tuned cars will show up weaknesses, typically in the turbochargers, clutch and internal engine components. Whilst most engines can cope with mild tuning mods, TorqueCars recommend that you upgrade the internal components before these weak spots manifest themselves.

  3. Mods that Remove a Restriction

    A restricted intake or exhaust will have an impact on your performance, so use a better flowing air filter/induction kit and better flowing exhaust (sports cats where legal are a good option) whenever your tuning creates a flow restriction. Turbo engines also benefit from intercooler upgrades as these resist heat soak for longer periods of time.

  4. Mods that Improve Fuelling

    Every tuning project will aim to increase the air supply, but fuel supply is just as vital and will need to match the air the engine can utilise,  a fuel pump and injector upgrade are usual mods, but also in many cases the fuel regulator will need improvement.

  5. Mods to Provide better Airflow

    Increasing the air supply is just as essential as improving fuelling, we suggest you look at head mods (flowing and porting, 5 angle valve jobs), fit bigger valves, fast road cams and forced induction upgrades (adding a better flowing turbo) to improve air intake.

M271 Tuning Stages

Stage 1 M271 modifications: Panel air filters, Sports exhaust manifold, Intake headers, Drilled & smoothed airbox, Remaps/piggy back ECU, Fast road camshaft.

Stage 2 M271 modifications: Fast road cam, fuel pump upgrades, Sports catalyst & performance exhaust, induction kit, high flow fuel injectors, Ported and polished head.

Stage 3 M271 modifications: Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Competition cam, Crank and Piston upgrades to alter compression, Twin charging conversions.

The M271 engines respond well to mods and thanks to their popularity there are quite a few choices of upgrades and performance parts around.

Remaps helps fully realize the full potential of all the upgrades you've done to your M271.

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 depend much on the upgrades you've carried out and the condition of your engine.

It is the main goal to any engine upgrade project to pull air into your M271

Headers transmit the air from the filter and allow it to be sucked into the engine and mixed with fuel.

The shape and rate of flow of the Plenum can make a substantial improvement to fuel delivery on the M271.

Most headers are needing motorsport parts, although some manufacturers provide fairly well optimized headers.

Adding a M271 larger valve kit, getting port work and head flowing will also improve bhp and torque, and importantly will permit increasing the bhp and torque increase on other tuning mods.

Turbo upgrades for the M271

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 M271

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

If your motor has forced induction tuning parts are simpler to install and we find turbocharged engines are built using uprated components.

There are tuning limits for every engine, with some being very over engineered and some only able to handle stock power

Research these limits and upgrade to forged components to survive the power.

It's not unheard of mechanics spending a loads on turbo upgrades on the M271 only to suffer the humiliation of seeing the engine throw a rod soon after it's used in anger.

Larger capacity turbo chargers commonly suffer a bottom end lag, and smaller turbo chargers spool up more quickly but do not have the peak end torque gains.

We are pleased that the selection of turbo units is always improving and we commonly find variable vane turbo units, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo units divert the exhaust flow into two channels and feed these at differently angled vanes in the turbo charger. They also help the scavenging effect of the engine.

It is not unusual that there's a restriction in the air flow sensor (AFM/MAF/MAP) on the M271 when loads 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 limited power at a much lower level.

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

Uprating M271 fuel injectors

Don't miss you'll need to ramp up the fuel delivery when you are increasing the torque - it makes the car more thirsty. It makes sense to be generous with your injectors flow rate.

As a rule of thumb add 20% capacity when fitting an injector, which takes into account injector deterioration and gives 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 M271 performance exhausts

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

On most factory exhausts you'll find your 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.

Sports exhausts can help increase the flow of air through the engine.

But if your exhaust pipe is too large, ie: over 2.5 inches bore, you will lose much of the exhaust flow rate and end up lacking power and torque.

Common exhaust restrictions can be located the emissions filters installed, so adding a faster flowing race alternative will help avoid this restriction.

Problems and issues to look out for on the M271

The M271 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M271, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M271 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M271 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 M271 guides and tips are kept up to date.

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