Modding tuning and best performance upgrades on the Mercedes M285 engine!

Tuning guide "M285 Modifications"

M285 Modifications Guide

How to modify and upgrade the Mercedes M285

"Comprehensive guide to tuning the Mercedes M285 engine!"

Popular tuning sites like TorqueCars are frequently getting emails requesting info on how to improve the M285 from people inquiring about getting more power from the M285 and wanting to know what are the things tuners are recommending when it comes to M285 mods that work. So let us look into Mercedes M285 parts and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

Now we shall review and look at M285 tuning and outline the best modifications. Mercedes M285 make awesome project engines and with carefully chosen sports parts like ECU maps, turbo kits and camshafts you will positively maximise your driving opportunities.

Just because particular tuning parts are appear in lots of M285 projects it doesn't mean you should fit it, so we'll focus on the optimum tuning parts that will give your M285 the best power gain for you spend.

Without us subscribing to the common myth of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

M285 induction kits

Improving air intake on the M285

You need fuel and air for an engine to work. If there is insufficient fuel then it will run lean, if there is not enough air it runs rich resulting in lost power which risks damage to the M285. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pushing air and fuel into the M285 engine is the primary aim to any engine upgrade job.

It is not unusual that there is a limit in the air flow sensor MAF/MAP on the M285 when a lot more air is being sucked into the engine.

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

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

The size of bore and shape and flow characteristics of the Plenum can make a big improvement to fuel atomisation and engine efficiency on the M285.

Commonly we find the plenum chambers are needing a performance upgrade, although a few manufacturers provide reasonably good plenum chambers.

Increasing the M285 valve size, doing a bit of port work and head flowing will also raise bhp, and as an added benefit will make space for a better bhp increase on other upgrades.

M285 performance cam tips.

Some M285 engines respond better to mild camshaft durations than others.

The engine timing and injectors and fuel pump also have an effect 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.

Altering your M285 camshaft will make a dramatic difference to the engine bhp. Choosing a higher performance camshaft profile raises the bhp accordingly.

NB: Fast road camshafts commonly raise the bhp throughout the rev range, you might lose a little low down torque but higher rpm power will be higher.

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

In a typical daily driver you need to optimize your torque band to your preferences.

I'd be gobsmaked if you find a M285 Competition camshaft is a pleasure to live with when driving around busy urban areas.

Stage 1, 2 and 3 mods for the M285

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 M285 parts:

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

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

Stage 2 M285 parts:

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

Stage 3 M285 parts:

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

The M285 units make great tuning projects and thanks to their popularity there are plenty of modifications and performance parts about.

ECU mapping will help to establish the full potential of all the tuning parts you've done to your M285.

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 your mileage usually depend much on the tuning parts you've done and the condition of your engine.

Turbo modifications on the M285

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 M285.

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.

When your car has a turbo already fitted upgrades are going to net you a larger power gain and we find turbocharged engines are built with uprated components.

There are tuning limits for every engine, with some being over specified and some just sufficiently able to handle stock power

Research these limits and upgrade to better quality components to cope with the power.

We've seen mechanics spending a loads on turbo charger upgrades on the M285 only to have the M285 catastrophically fail on it's first outing after it's been finished.

Big upgraded turbos will usually experience no power at low rpm, and small turbos spool up much more quickly but do not have the peak rpm torque gains.

Over the last 20 years the range of turbochargers is always evolving and we are seeing variable vane turbochargers, allowing the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbochargers divert the exhaust gases into two channels and direct these at differently designed vanes in the turbocharger. They also help 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 install. We have this article covering twinchargers if you want to read more.

Tips about fuel supply on the M285

Don't overlook the need to improve the fuel delivery when you are increasing the bhp - it makes the car more thirsty. Experienced tuners recommend to over specify your injectors flow rate.

The rule of thumb is to add 20% to the flow rate when buying an injector, this accounts for injector deterioration and gives you some 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 M285 performance exhaust upgrades

You may need to increase your exhaust system with an upgraded one is if your current exhaust is actually creating a flow problem.

On most factory exhausts you should find that the exhaust 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.

Sports exhausts will certainly help air flow through the engine but avoid an exhaust that is too large or you may end up will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

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

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

Faults issues and things to look out for on the M285

Like most engines an M285, 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 M285, failure to do this will exacerbate engine wear, on a tuned M285 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 M285 why not pop over to the forums at TorqueCars where you can chat about M285 tuning options and read about others projects who may be planning to do similar modifications on their M285.

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