Tuning the BMW M44

"Building the best modified BMW M44 engine!"

Carref prides itself on providing the latest tips and guides to your modification project.

Herein we examine M44 tuning and summarise the premier modifications for your car. BMW M44 make awesome project engines and with the best uprated upgrades like remapping, turbo improvements and camshafts you will maximise your driving fun.

We rely on our visitors to pass on tips and tell us about their projects and what worked on their car, and this article is the culmination of the feedback we have received. First let us look at the history and specs of this engine and then consider which tuning modifications work best on it.

History of the Engine

The M44 is a DOHC four-cylinder petrol engine which replaced the BMW M42

• M44B19 from 1996-2000
  1,895 cc (115.6 cu in)
• 103 kW (138 bhp) at 6,000 rpm 180 N⋅m (133 lb⋅ft)  at 4,300 rpm

Tuning the BMW M44 and best M44 performance parts.

What are the most effective M44 modifications

The top M44 upgrades on an engine are sensibly the ones that give the biggest return for your cash.

We won't be swayed by popular M44 upgrades, they need to be cost effective.

Significant gains on the M44 can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

Fast road camshafts usually bump the performance over the rev band, you could sacrifice a little low down torque but higher rpm power will be higher.

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

For a car driven daily must carefully try to match your power band to your driving style.

I'd be shocked find a M44 Motorsport camshaft is a pleasure to live with when in heavy traffic.

Some M44 engines respond better to extreme cam durations so set your engine up on a rolling road.

The engine timing and injectors and fuel pump also have a large bearing on the torque gains you'll achieve.

Altering valve 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.

Modifying to STAGE 1:

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

Modifying to Stage 2:

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

Modifying to Stage 3:

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

ECU mapping allows a tuner to unlock the full potential of all the modifications you've done to your M44.

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

It is the main goal to any engine upgrade task to get air into the M44 engine

Headers flow the air from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

Design and rate of flow of the Headers can make a big improvement to fuel atomisation on the M44.

We often see plenum chambers are needing performance upgrades, although some OEM provide well optimised plenum chambers.

Larger M44 valves, doing some M44 port enlargement and head flowing will also boost performance, and significantly will make space for a better performance increase on other tuning mods.

Which turbo upgrades are best?

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 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 massive power gains.

If a car has a turbocharger tuning mods are going to make more power and you'll see that turbo engines already contain uprated components.

However you will find an engines will need better parts at higher power limits

Discover these restrictions and install forged components to utilize the power.

There are many drivers spending a lots of money on turbo upgrades on the M44 only to have the car explode on it's first outing after it's completed.

Big upgraded turbochargers often experience low end lag, and small turbochargers spool up really quickly but won't have the high rpm engines power gains.

Thankfully the choice of turbos is always increasing and we commonly find variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust flow into a couple of channels and push these at differently designed vanes in the turbocharger. They also increase the scavenging effect of the engine.

It is common that there is a limitation in the air flow sensor (AFM/MAF/MAP) on the when loads more air is being drawn into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped power at a much lower level.

Adding a supercharger or additional turbo will make large torque gains, although more challenging to configure. We have this guide to twinchargers if you want to read more.

Fuelling

Don't overlook the need to boost the fuel delivery when you are increasing the torque - it makes the car more thirsty. It is important to over specify your flow rate on the injectors.

The accepted safe increase is to add 20% when specifying an injector, this accounts for injector deterioration and gives a bit of 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.

All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

4 Cylinder turbocharged engines

• 58 PSI 340cc/min 200hp
• 58 PSI 511cc/min 300hp

4 Cylinder NASP engines

• 58 PSI 285cc/min 200hp
• 58 PSI 426cc/min 300hp

4 Cylinder supercharged engines

• 58 PSI 312cc/min 200hp
• 58 PSI 468cc/min 300hp

Choosing the right performance exhaust

One of the most common mistakes and problems we see in tuning projects is usually down to the exhaust, or rather a poorly chosen exhaust for your engine.

You may need to uprate your exhaust if the existing exhaust is actually creating a restriction in flow.

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

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

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

Weak spots Issues & problem areas on the M44

The engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the M44, especially when tuned and will help extend the life and reliability of the engine.

For more information on Tuning your engine please join us in our friendly forum where you can discuss M44 tuning options in more detail with our owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which upgrades work best for them on each model of car. Comments are used to improve the accuracy of these articles which are continually updated.

This article was written by Waynne Smith on TorqueCars, and I appreciate your feedback and suggestions. This entry was filed under BMW. You can leave a response below or join TorqueCars forum to discuss this article and car modification in detail with our members.

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