Modding and performance tuning parts for the BMW M47 engine!

Tuning guide "M47 Modifications"

M47 Modifications Guide

How to modify and upgrade the BMW M47

"Comprehensive guide to performance tuning the BMW M47 engine!"

Popular tuning sites like TorqueCars are always seeing threads asking about how to improve the M47 from people inquiring about getting more power from the M47 and wanting to know what are the ultimate M47 mods that work. So let us look into BMW M47 upgrades and outline the best modifications on this great engine and point out some potential pitfalls along the way.

The BMW M47 are good project engines and with the ultimate upgrades like ECU maps, turbo upgrades and camshafts you will noticeably increase your driving enjoyment.

Our aim here is to provide a guide to M47 tuning and highlight the greatest modifications.

When talking about the optimum parts for your M47 engine, we are going to focus on the parts that give the best value for money.

M47 induction kits

Improving air intake on the M47

You need air and fuel for an engine to work. If there is too little fuel then it will run lean, if there is insufficient air it runs rich losing power which risks damage to the M47. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pulling more air and fuel into the M47 engine is the main goal to any performance tuning job.

You'll commonly see there is a restriction in the air flow sensor MAF/MAP on the M47 when a lot more air is being fed 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 was restricting torque at a much lower level.

The intake plenum take the on the suck phase from the filter and allow it to be fed into the engine cylinders.

Shape and flow characteristics of the Air Intake manifolds can make a large improvement to fuel delivery on the M47.

I usually find headers are needing an upgrade, although a few car makers provide reasonably good headers.

Larger M47 valves, doing some M47 port enlargement and head flowing will also raise performance, and more importantly will allow you to get increasing the performance increase on other parts.

M47 performance cam tips.

Some M47 engines respond better to more or less aggressive camshaft durations check your engine on a rolling road.

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

A longer valve duration can alter the power 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 M47 camshaft will make a dramatic difference to the engine bhp. Choosing a higher performance camshaft profile raises the bhp accordingly.

NB: Fast road camshafts usually push up the bhp across the rpm band, you might lose a little low down bhp but your top end will improve.

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

On a daily driver you must carefully try to match your engines power to your preferences.

You will never have found a M47 Race camshaft is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the M47

Stage 1 M47 parts:

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

Stage 2 M47 parts:

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

Stage 3 M47 parts:

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

Carefully think through your options and then acquire your tuning parts and set yourself a power target to avoid disappointment.

Remaps allows a tuner to to establish the full potential of all the upgrades you've done to your M47.

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

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 power output usually depend much on the upgrades you've done and the condition of your engine.

Turbo modifications on the M47

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 M47.

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes impressive power gains.

When your car is fitted with a turbocharger modifications are giving better power gains and most turbo engines already contain harder and stronger components.

There are reliable limits for every engine, with some being very over engineered and some only able to handle stock power

See where you'll find these restrictions and upgrade to higher quality components to survive the power.

There are many car owners spending a lots of money on turbocharger upgrades on the M47 only to suffer the indignity of watching the whole thing throw a rod just after it's finished.

Large capacity turbo chargers commonly suffer no power at low rpm, and little turbo chargers spool up quickly but won't have the peak rpm torque gains.

Thanks to new tech the world of turbos is always developing and we commonly find variable vane turbos, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust flow into 2 channels and direct these at differently angled vanes in the turbo charger. 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 install. We have this article covering twinchargers if you want to read more.

Tips about fuel supply on the M47

Don't overlook the need to pay attention to the fuelling when you are increasing the performance - it makes the car more thirsty. It makes sense to over specify your injectors flow rate.

As a rule of thumb add another 15% when specifying an injector, which takes into account injector deterioration and gives 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 M47 performance exhaust upgrades

We'd only recommend you look to replace your exhaust system with an upgraded one is if your exhaust is actually causing 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 can help balance the flow of air through the engine.

But if the exhaust is too big, ie: over two and a half inches diameter, you will lose much of your flow rate and end up losing power and torque.

Usual exhaust restrictions can be traced to the emissions filters installed, so adding a better flowing sports 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 M47

Like most engines an M47, 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 M47, failure to do this will exacerbate engine wear, on a tuned M47 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 M47 why not pop over to the forums at TorqueCars where you can chat about M47 tuning options and read about others projects who may be planning to do similar modifications on their M47.

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