Guide to tuning the N14 engine from BMW

"BMW N14 Tuning"

Tuning the BMW N14 and best N14 performance parts.

We review N14 tuning and point out the best mods that work. BMW N14s are good project cars and with carefully chosen performance parts you can maximise your driving pleasure.

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 N14 Engine

The engine was developed jointly with the PSA group and BMW, and the PSA group branded the engine "Prince".

See the PSA prince tuning article for more on this engine.

Prince won many awards in it's production a great reward for this collaboration.

The N14 was used in the Mini N14

Replaced the N13 and we see direct injection valvetronic and twin scroll turbo charger technology included in this engine.

What are the most effective N14 modifications

The ultimate parts on an engine are in our opinion the ones that give the biggest return for your cash.

We won't be swayed by popular N14 parts, they need to be cost effective.

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

Fast road camshafts usually push up the power over the rev band, you may sacrifice a little bottom end torque but higher rpm power will be lifted.

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

On a typical daily driver you need to match your bhp range to your typical driving style.

I'd be amazed if you have thought a Competition cam is a pleasure to live with when driving in heavy traffic.

Different N14 engines respond better to less aggressive camshaft durations than others.

The ECU mapping and fuel pump and injectors also have an effect 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.

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Modifying to Stage 1:

 Remaps, Intake headers, Sports exhaust manifold, Panel air filters, Fast road camshaft, .

Modifying to Stage 2:

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

Modifying to Stage 3:

 Competition cam, Engine balancing & blueprinting, Twin charging conversions, Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (pistons/head/valves)

Remaps allows a tuner to to establish the full potential of all the tuning mods you've done to your N14.

It will usually give around 30% more power on turbocharged vehicles and 15% on NASP engines, but you mileage will vary depending on the tuning mods you've done and the condition of your engine.

It is vital to any tuning task to shove more fuel and air into each cylinder

Air Intake manifolds flow the air during the suck phase from the air filter and allow it to be pulled into the engine cylinders.

The bore size, shape and flow characteristics of the Air Intake manifolds can make a large effect on to fuel mixing and power on the N14.

Many mass produced engine intake manifold are in dire need of an upgrade, although a few manufacturers provide well optimised intake manifold.

Big valve conversions on the N14, doing a bit of port work and head flowing will also improve power, this will allow you to get a better power increase on other mods.

N14 turbo upgrades - which are best?

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

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 N14

When an engine has a turbo already fitted tuning parts are more reliable and you will discover turbo engines are made with better components.

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

Research these limitations and fit stronger pistons, crank and engine components to utilize the power.

It's not unheard of drivers spending a lots of money on turbo charger upgrades on the N14 only to exprience the whole thing explode when it's first rolling road session.

Bigger turbo chargers tend to suffer a bottom end lag, and smaller turbo chargers spool up more quickly but do not have the peak end torque gains.

In the last 10 years the world of turbochargers is always improving and we now see variable vane turbochargers, where the vane profile is altered according to speed to lower lag and increase top end bhp.

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

It is common that there's a limitation in the air flow sensor AFM/MAF on these engines when considerably more air is being fed into the engine.

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

Adding a supercharger or additional turbo will make large bhp and torque gains, although more challenging to install. We have a twincharger bhp and torque adding guide if you want to read more.

Fuelling

You will need to ensure that the engine is not starved of fuel so should look at the fuelling when you start exceeding 20% of a power increase.We would recommend you to over specify your injector capacity.

As a rule of thumb add 20% to the flow rate when specifying an injector, which takes into account injector deterioration and provides some spare capacity should the engine need more fuel.

N14 Exhaust

You should look to uprate your exhaust if the current exhaust is actually creating a restriction.

On most factory exhausts you'll see the flow rate quite well 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 can help increase the flow of air through the engine.

But if the exhaust is too large, ie: over 2.5 inches bore, you will lose much of the flow rate and end up sapping power and torque.

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

Weakspots and problem areas on the N14

The N14 engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the N14, especially when tuned and will help extend the life and reliability of the engine.

Carbon build up has been noted, and we recommend a good regular thrash with some BG fuel cleaner to keep on top of things.

For more information on Tuning your BMW engine please join us in our friendly forum where you can discuss N14 tuning options in more detail with our N14 owners. It would also be worth reading our unbiased BMW 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 mods 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, Mini. 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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