Tuning the Mercedes M273

"Comprehensive guide to performance tuning the Mercedes M273 engine!"

We are frequently getting messages inquiring about getting more power from the M273 and wanting to know what are the things we recommend when it comes to M273 power upgrades. So let us look into Mercedes M273 parts and outline the best mods that work on this great engine and point out some problems along the way.

This pages aim is review and look at M273 tuning and provide tips on the premier mods that work. Mercedes M273 make awesome project engines and with the best modified mods like remapping, turbo kits and camshafts you will noticeably maximise your driving fun.

Just because particular modifications are popular with M273 owners it doesn't mean it is good, instead we will focus on the modifications that will give your M273 the best power gain for you spend.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large power band gains are on offer for cam upgrades.

NB: Fast road cams usually increase the performance through the rpm band, you may sacrifice a little low down power but the higher rpm power will be higher.

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

In a daily driver must carefully try to match your bhp range to your preferences.

I would be surprised if you have found a M273 Race cam is a pleasure to live with when driving around busy urban areas.

Different M273 engines respond better to mild camshaft durations so view each engine as unique.

The ecu map and fuelling also will say much on the power gains you'll achieve.

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.

M273 Tuning Stages

Stage 1 M273 modifications: Fast road camshaft, Drilled & smoothed airbox, Sports exhaust manifold, Remaps/piggy back ECU, Panel air filters, Intake headers.

Stage 2 M273 modifications: Ported and polished head, induction kit, high flow fuel injectors, fuel pump upgrades, Fast road cam, Sports catalyst & performance exhaust.

Stage 3 M273 modifications: Twin charging conversions, Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Competition cam, Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger).

A remap allows a tuner to fully realize the full potential of all the parts you've done to your M273.

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

It is the aim to any engine upgrade job to feed more air into each cylinder

Intake transmit the air during the suck phase from the air filter and allow it to be fed into the engine cylinders with fuel for the squish phase.

The shape and rate of flow of the Intake can make a noticeable difference to to fuel delivery on the M273.

We often see intake manifold are in dire need of an upgrade, although a few makers provide reasonably well designed intake manifold.

Increasing the M273 valve size, carrying out 3 or 5 angle valve jobs and porting and head flowing will also lift bhp, & importantly will raise potential for a better bhp increase on other parts.

Turbo upgrades for the M273

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 M273

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

If an engine is turbo charged tuning mods are simpler to install and we find turbo engines are made with uprated components.

However you will find an engines have weakspots

We recommend you find these restrictions and install higher quality crank and pistons to utilize the power.

It's not unheard of car owners spending a a stack of money on turbo charger upgrades on the M273 only to suffer the humiliation of seeing the M273 go up in smoke soon after it's been finished.

Big turbochargers tend to suffer no power at low rpm, and smaller turbochargers spool up quickly but don't have the peak end engines power gains.

We are pleased that the choice of turbochargers is always evolving and we now see variable vane turbochargers, permitting the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbochargers divert the exhaust flow into 2 channels and push these at differently angled vanes in the turbo. They also help the scavenging effect of the engine.

It is not unusual that there's a limitation in the air flow sensor MAP/MAF/AFM on the M273 when considerably more air is being drawn into the engine.

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

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

Uprating M273 fuel injectors

When you lift the torque you will need to look at to the fuelling.

More torque needs more fuel. Don't forget to over specify your flow rate on the injectors.

The rule of thumb is to add 20% when fitting an injector, this takes into account injector deterioration and provides 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 M273 performance exhausts

Only look to replace your exhaust if your exhaust is actually creating a flow problem.

On most factory exhausts you'll find your flow rate is still good 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 you'll slow the exhaust 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.

Common exhaust restrictions can be traced to the filters installed, so adding a better flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the M273

The M273 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M273, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M273 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M273 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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We really like hearing from our readers, and hearing about which tuning parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our M273 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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