Modding and performance tuning parts for the Mercedes M274 engine!

All you need to know about "M274 Modifications"

M274 Modifications Guide

How to modify and upgrade the Mercedes M274

"Comprehensive guide to tuning the Mercedes M274 engine!"

TorqueCars are regularly seeing threads asking how to improve the M274 from people inquiring about getting more power from the M274 and wanting to know what are the best tips on M274 power upgrades. So let us look into Mercedes M274 upgrades and outline the best upgrades on this great engine and point out some frequent tuning mistakes along the way.

This pages aim is detail the best approach to M274 tuning and point out the greatest mods that work. Mercedes M274 are fantastic to work on and with a few sensible performance parts like remaps, turbo improvements and camshafts you will really increase your driving fun.

When talking about the best parts for your M274 engine, we are going to focus on the modifications that give the biggest return for your cash.

M274 induction kits

Improving air intake on the M274

You need air matched to fuel for an engine to work. If there is a lack of fuel then it will run lean, if there is not enough air it runs rich losing power . We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the fundamental goal to any tuning job to feed fuel and air into each cylinder but this has a knock on effect with the air flow sensor.

It is common that there is a limit in the air flow sensor MAP/MAF/AFM on the M274 when loads 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 limited torque at a much lower level.

The intake plenum take the air during the suck phase from the air filter and allow it to be sucked into the engine cylinders with fuel for the squish phase.

Shape and flow rate of the Intake headers can make a substantial effect on to fuel atomisation and engine efficiency on the M274.

Commonly we find the intake headers are improved through an upgrade, although some car makers provide decently flowing intake headers.

Adding a M274 larger valve kit, carrying out 3 or 5 angle valve jobs and porting and head flowing will also raise power, the fantastic side effect is it will make space for a greater power increase on other upgrades.

M274 performance cam tips.

Each engine responds better to more aggressive camshaft durations so set your engine up on a rolling road.

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

Extending exhaust or intake durations 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.

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

NB: Fast road camshafts usually bump the torque through the rpm range, you might lose a little bottom end torque but the high end rpm power will be lifted.

Motorsport camshafts, bump the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

For a road car you need to optimize your engines power to your preferences.

I'd be gobsmaked if you have ever thought a M274 Motorsport and race cam is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the M274

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 M274 parts:

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

Stage 2 M274 parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 3 M274 parts:

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

The M274 engines respond well to upgrades and we're happy to report there are increasing numbers of mods and performance parts about.

A remap will help unlock the full potential of all the parts you've done to your M274.

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 power output usually depend much on the parts you've carried out and the condition of your engine.

Turbo modifications on the M274

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 M274.

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

If an engine is turbo charged modifications are more reliable and you will discover turbo charged engines use uprated components.

There are common areas of failure for every engine, with some being extremely strong and some only just able to handle stock power

Discover these restrictions and fit more solid crank and pistons to utilize the power.

We see many car owners spending a a stack of money on turbo upgrades on the M274 only to suffer the humiliation of seeing the M274 explode when it's been finished.

Bigger turbo units often suffer a bottom end lag, and low capacity turbo units spool up really quickly but don't have the peak rpm engines power gains.

Thankfully the choice of turbo chargers is always evolving and we now see variable vane turbo chargers, permitting the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo chargers divert the exhaust gases into 2 channels and push these at differently profiled vanes in the turbocharger. They also improve the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large performance gains, although more complex to get working. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the M274

Don't miss you'll need to raise the fuel system when you are increasing the bhp and torque - it makes the car more thirsty. We would recommend you to be generous with your injectors flow rate.

The accepted safe increase is to add 15% to the flow rate when specifying an injector, which takes into account injector deterioration and affords a little spare capacity should the engine require 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 M274 performance exhaust upgrades

We'd only recommend you look to replace your exhaust system with an upgraded one is if the current exhaust is creating a restriction in flow.

On most factory exhausts you should find that your flow rate is still good 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 largest exhaust you can buy this will reduce the exhaust flow rate - the best exhausts 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.

The usual suspects causing problems in your exhaust flow rate are traced to the catalyst installed, so adding a better flowing race alternative will help avoid this restriction.

Decats (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the M274

Like most engines an M274, 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 M274, failure to do this will exacerbate engine wear, on a tuned M274 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 M274 why not pop over to the forums at TorqueCars where you can chat about M274 tuning options and read about others projects who may be planning to do similar modifications on their M274.

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