Modding upgrading and tuning the BMW M44 engine!

Discover "M44 Modifications"

How to modify and upgrade the BMW M44

"Comprehensive guide to tuning the BMW M44 engine!"

Sites like TorqueCars often are getting messages asking how to improve the M44 from people wanting to know what are the best tips on M44 power upgrades. So let us look into BMW M44 parts and outline the best upgrades on this great engine and point out some common pitfalls along the way.

Here we provide a guide to M44 tuning and summarise the premier mods that work. BMW M44 make a good tuning project and with a few sensible sports upgrades like a remap, turbo kits and camshafts you will noticeably enhance your driving enjoyment.

Just because particular upgrades are appear in lots of M44 projects it doesn't mean you should fit it, instead we'll focus on the best upgrades that will give your M44 the best power gain for you money.

Without us subscribing to the misaprehension 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'.

M44 induction kits

Improving air intake on the M44

You need air matched to fuel for an engine to work. If there is little supply of fuel then it will run lean, if there is insufficient air it runs rich resulting in lost power which risks damage to the M44. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Getting fuel and air into your M44 is the whole point to any tuning job.

You'll commonly see there's a limit in the air flow sensor MAF/MAP on the M44 when a lot more air is being fed into the engine.

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

Air Intake manifolds flow the air during the suck phase from the filter and allow it to be sucked into the engine cylinders with fuel for the squish phase.

The size of bore and shape and flow rate of the air Intake manifold can make a noticeable change to fuel atomisation on the M44.

Many mass produced engine intake are needing an upgrade, although a few makers provide decently flowing intake.

Increasing the M44 valve size, doing some port work and head flowing will also raise power, & importantly will raise potential for a greater power increase on other tuning parts.

M44 performance cam tips.

Some M44 engines respond better to more aggressive cam durations check your engine on a rolling road.

The map and fuel pump and injectors also have an effect on the torque gains you'll make.

A longer valve duration 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.

Significant air intake, and exhaust improvements on the M44 can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

NB: Fast road cams tend to boost the bhp and torque across the rev range, you might lose a little bottom end bhp but your higher rpm power will be better.

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

A Motorsport cam won't do well if in heavy traffic.

You should ideally match your power band to your preferences so for a car driven daily stick with a fast road M44 cam

Stage 1, 2 and 3 mods for the M44

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 M44 parts:

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

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

Stage 2 M44 parts:

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

Stage 3 M44 parts:

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

The M44 engine blocks make great tuning projects and we're happy to report there is a lot of modifications and performance parts around.

ECU mapping allows a tuner to to establish the full potential of all the tuning mods you've done to your M44.

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 results usually rely on the tuning mods you've applied and the condition of your engine.

Turbo modifications on the M44

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 M44.

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 upgrades are going to make more power and most turbo charged engines are made with stronger components.

However you'll find engines will have power limits

Research these limitations and upgrade to better quality components to handle the power.

It's not unheard of mechanics spending a loads of money on turbocharger upgrades on the M44 only to have the whole thing go up in smoke just after it's been finished.

Large upgraded turbochargers will usually suffer low end lag, and smaller turbochargers spool up really quickly but won't have the top end engines power gains.

Thankfully the market of turbo chargers is always developing and we now see variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbo chargers divert the exhaust gases into 2 channels and feed these at differently profiled vanes in the turbo charger. 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 bhp gains, although more complex to setup. We have this article on twincharging if you want to read more.

Tips about fuel supply on the M44

Don't omit to look at the fuel system when you are increasing the performance - it makes the car more thirsty. It makes sense to over specify your injectors flow rate.

The rule of thumb is to add 15% when fitting an injector, this accounts for injector deterioration and provides some spare capacity should the engine need 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 M44 performance exhaust upgrades

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

On most factory exhausts you'll find the exhaust flow rate is ok 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 increase the flow of air through the engine.

But if the exhaust pipe is too large, ie: it's over two and a half inches diameter, you will lose much of the flow rate and end up lacking power and torque.

Usual exhaust restrictions come around the filters installed, so adding a freer 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 M44

Like most engines an M44, 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 M44, failure to do this will exacerbate engine wear, on a tuned M44 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 M44 why not pop over to the forums at TorqueCars where you can chat about M44 tuning options and read about others projects who may be planning to do similar modifications on their M44.

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