Modding upgrading and tuning the BMW M50 engine!

Car tuning tips:M50 Modifications"

M50 Modifications Guide

How to modify and upgrade the BMW M50

"Comprehensive guide to performance parts and tuning the BMW M50 engine!"

TorqueCars are regularly seeing threads requesting information on how to improve the M50 from people inquiring about getting more power from the M50 and wanting to know what are the ultimate M50 modifications. So let us look into BMW M50 parts and outline the best modifications on this great engine and point out some problems along the way.

The BMW M50 great bases for a tuning project and with carefully picked sports modifications like remaps, turbo improvements and camshafts you will greatly enhance your driving pleasure.

This pages aim is consider M50 tuning and point out the greatest mods that work.

The ultimate M50 parts on an engine are obviously the ones that give the best power gain for your hard earned cash.

We won't be swayed by popular M50 parts, they need to be cost effective.

M50 induction kits

Improving air intake on the M50

You need air matched to fuel for an engine to work. If there is not enough fuel then it will run lean, if there is a lack of 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 Forcing more fuel and air into the M50 engine is vital to any car tuning task.

It is common that there is a limitation in the air flow sensor AFM/MAF on the M50 when loads more air is being pulled into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped torque at a much lower level.

Air Intake manifolds flow the on the suck phase from the filter and allow it to be drawn into the engine and mixed with fuel.

Design and flow characteristics of the Air Intake manifolds can make a noticeable difference to to fuel atomisation and engine efficiency on the M50.

On popular production engines intake headers are ripe for performance upgrades, although some car makers provide fairly well optimized intake headers.

Big valve conversions on the M50, doing some port work and head flowing will also raise bhp, and significantly will make space for a better bhp increase on other parts.

M50 performance cam tips.

Some M50 engines respond better to extreme camshaft durations so view each engine as unique.

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

Longer 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.

Significant air intake, and exhaust improvements on the M50 can be made from camshaft upgrades. Changing the camshaft 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 push up the bhp across the rev range, you might lose a little low end power but high end rpm power will be lifted.

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

A Motorsport camshaft is not great driving in heavy traffic.

You should ideally match your torque band to your usage of the car so for a car driven daily stick with a mild fast road M50 camshaft

Stage 1, 2 and 3 mods for the M50

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 M50 parts:

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

Stage 2 M50 parts:

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

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

Stage 3 M50 parts:

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

Review your options and then acquire your modifications and set yourself a power target to avoid disappointment.

ECU flashing will help to establish the full potential of all the modifications you've done to your M50.

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 the end result usually differs on the modifications you've applied and the condition of your engine.

Turbo modifications on the M50

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 M50.

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 your car is fitted with a turbo tuning parts are giving better power gains and turbo charged engines are built with strengthened components.

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

Discover these limits and fit stronger pistons, crank and engine components to utilize the power.

There are many people spending a a stack of money on turbo upgrades on the M50 only to watch the car go up in smoke just after it's been finished.

Larger capacity turbochargers often experience low end lag, and smaller turbochargers spool up more quickly but won't have the peak end engines power gains.

Thanks to progress the choice of turbo chargers is always developing and we now see variable vane turbo chargers, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and direct these at differently angled vanes in the turbo. They also increase 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 difficult to configure. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the M50

Don't dismiss the need uprate the fuel system when you are increasing the bhp - it makes the car more thirsty. Care modifiers usually say to be generous with your flow rate on the injectors.

The rule of thumb is to add another 15% when specifying an injector, this takes into account injector deterioration and provides a little 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 M50 performance exhaust upgrades

You only need to to replace your exhaust system with an upgraded one is if your current exhaust is actually causing a restriction in flow.

On most factory exhausts you'll see the exhaust flow rate is still fine 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 can help increase the flow of gases through the engine.

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

Typically exhaust restrictions come around the catalysts installed, so adding a faster flowing sports alternative will help avoid this restriction.

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

Faults issues and things to look out for on the M50

Like most engines an M50, 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 M50, failure to do this will exacerbate engine wear, on a tuned M50 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 M50 why not pop over to the forums at TorqueCars where you can chat about M50 tuning options and read about others projects who may be planning to do similar modifications on their M50.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We want to know your experiences with upgrades on your M50, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article