Modding and performance tuning parts for the BMW M52 engine!

Tuning guide "M52 Modifications"

M52 Modifications Guide

How to modify and upgrade the BMW M52

"Comprehensive guide to performance parts and tuning the BMW M52 engine!"

Our friends at TorqueCars are frequently getting messages requesting information on how to improve the M52 from people inquiring about getting more power from the M52 and wanting to know what are the greatest M52 mods that work. So let us look into BMW M52 mods and outline the best mods that work on this great engine and point out some potential pitfalls along the way.

Now we shall review and look at M52 tuning and report on the best modifications. BMW M52 are popular tuning projects and with the optimum modified mods like a remap, turbo upgrades and camshafts you will definitely enhance your driving experience.

When talking about the top parts for your M52 engine, we are going to focus on the parts that give the best value for money.

M52 induction kits

Improving air intake on the M52

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

So the whole point to any engine upgrade job to force air into your M52 but this has a knock on effect with the air flow sensor.

It is not unusual that there's a limitation in the air flow sensor (AFM/MAF/MAP) on the M52 when loads more air is being pulled into the engine.

When tuning you may well find you need to get an air sensor or flow meter capable of upto 4 bars to cope with quite large power gains, whereas the OEM air sensor sapped performance at a much lower level.

Air Intake manifolds transmit the air during the suck phase from the air cleaner and allow it to be sucked into the engine cylinders.

The bore size, shape and rate of flow of the Plenum can make a noticeable difference to to fuel atomisation on the M52.

Most air intake manifolds are in dire need of a performance upgrade, although a few OEM provide well optimised air intake manifolds.

Larger M52 valves, doing a bit of M52 port enlargement and head flowing will also raise power, & importantly will give you a greater power increase on other mods.

M52 performance cam tips.

Some M52 engines respond better to more aggressive 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 hit.

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.

Altering your M52 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road cams tend to bump the torque across the rpm range, you may sacrifice a little low end bhp but the top end will be better.

Motorsport and race cams, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

For a daily driver you should ideally to optimize your torque band to your preferences.

I'd be shocked if you find a M52 Motorsport and race cam is a pleasure to live with when on the daily commute.

Stage 1, 2 and 3 mods for the M52

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 M52 parts:

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

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

Stage 2 M52 parts:

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

Stage 3 M52 parts:

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

Review your options and then source your tuning mods and set yourself a power target to avoid disappointment.

Remaps helps fully realize the full potential of all the tuning parts you've done to your M52.

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 vary depending on the tuning parts you've fitted and the condition of your engine.

Turbo modifications on the M52

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 M52.

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 the engine has a turbocharger mods are relatively easy and most turbo engines are made with many forged and stronger components.

However engines have limits

Discover these limitations and install higher quality components to utilize the power.

We've seen car owners spending a lot of money on turbo upgrades on the M52 only to suffer the indignity of watching the engine catastrophically fail when it's been completed.

Bigger upgraded turbo units will usually experience low end lag, and smaller turbo units spool up quickly but do not have the peak end torque gains.

Thankfully the choice of turbos is always moving on and we are seeing variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbos divert the exhaust gases into a couple of channels and flow these at differently angled vanes in the turbo charger. 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 torque gains, although more difficult to get working. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the M52

You will need to ensure that the engine is not starved of fuel so need to uprate the fuelling when you start exceeding 20% of a power hike. Experienced tuners recommend to be generous with your injector capacity.

The rule of thumb is to add 15% capacity when buying an injector, which takes into account injector deterioration and gives a bit of 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 M52 performance exhaust upgrades

You should look to improve your exhaust system with an upgraded one is if the current exhaust is actually creating a flow problem.

On most factory exhausts you'll see 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.

Sports exhausts can usually air flow from the engine but avoid an exhaust that is too big or you could will reduce the flow rate. Stick to one and a half to two and half inches for best results.

Usual exhaust restrictions are in the filters installed, so adding a freer flowing high performance alternative will help avoid this restriction.

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

Faults issues and things to look out for on the M52

Like most engines an M52, 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 M52, failure to do this will exacerbate engine wear, on a tuned M52 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 M52 why not pop over to the forums at TorqueCars where you can chat about M52 tuning options and read about others projects who may be planning to do similar modifications on their M52.

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