Guide to tuning the N14 engine from BMW

"BMW N14 Tuning Mods"

The N14 "Prince" engine represents a departure from traditional engines, featuring innovative technology with a focus on performance and efficiency.

It incorporates direct fuel injection, a twin-scroll turbocharger, and Valvetronic variable valve lift, which collectively enhance power output and fuel efficiency.

The N14 is a very compact and lightweight engine, making it ideal for use in small and mid-sized vehicles. Its design maximizes power-to-weight ratio, contributing to improved performance.

The combination of direct fuel injection and Valvetronic technology allows the N14 engine to achieve impressive fuel efficiency.

Despite its small size, the N14 engine can produce a significant amount of power, making it versatile and suitable for various vehicle types, from compact cars to sporty models.

The N14 engine has proven to be highly tunable, which means it can be further enhanced for more power. Enthusiasts and tuners have successfully pushed this engine to achieve impressive performance figures with relatively simple modifications so let's discuss the upgrade options for this great little powerplant.

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.

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History, Power & Specs 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.

Best 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.

SCHRICK offer a decent upgraded cam profile, and we would recommend the titanium retainer also be fitted. Always check the valve clearance after a cam is fitted, BEFORE you even thing about starting the engine. Generally speaking though the Shrick 248 should be fine on stock pistons.

Newman cams are also worth considering, and these cams will net you around 17hp more power and improve your overall torque band.

Fast road camshafts typically increase power across the entire rev range, although there may be a slight trade-off in low-end torque to achieve higher RPM power gains.

It's crucial to note that when installing a camshaft, an ECU tune or remap is essential. This is because the different valve durations necessitate adjustments to the fuel and air tables to optimize engine performance.

On the other hand, competition camshafts primarily boost power in the higher RPM range.

However, a drawback is that the car may not idle smoothly, and low-end power often takes a hit. In a daily driver, it's vital to match the desired brake horsepower (bhp) range to your typical driving style.

If you've ever attempted to navigate heavy traffic with a competition cam, you'll likely find it far from enjoyable.

The low-end idle becomes erratic and rough, a characteristic that's less noticeable on a track when operating in the upper RPM band.

However, for road use, this can become a significant issue, leading to regrets among drivers who opt for an extremely aggressive competition cam profile.

It's important to understand that different N14 engines respond differently to camshaft durations.

Additionally, the torque gains you'll achieve are influenced by ECU mapping, fuel pump, and injectors.

Longer valve durations can modify the torque band, and while most camshafts and tuners use matched pairs of exhaust and intake durations, there are advantages to extending either the intake or exhaust durations in specific situations.

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Best mods for your N14

  1. Forced induction upgrades - forced induction is the most efficient approach to raise the intake air supply, which permits you to burn more fuel and make power gains. Although one of the most complex mods you'll see massive gains.
  2. Tunes - A Remapped N14 ECU provides the biggest gains in terms of cost, aftermarket ECUs, and inline Tuning boxes are all alternatives.
  3. Fast road Camshafts are significant power adders, but we strongly suggest they be installed by someone qualified to set them up and it is often hard to find a suitable cam near you but you'll probably find a local firm to regrind a stock camshaft .
  4. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.
  5. Air Induction and Sports Exhausts - Be aware on their own these mods will NOT ADD POWER in most cases, but they will enable you to release power after other upgrades by removing the restriction.
  6. Lighter flywheels - a reduced weight flywheel will improve the engines rev changes. In some cases flywheel lightening is not not a great upgrade for all N14 engines.

N14 Tuning Stages

Typical stage 1 mods often include: Remaps, Intake manifolds, Sports exhaust header/manifold, Panel air filters, Fast road camshaft, .

Typical stage 2 mods often include: Fast road cam, high flow fuel injectors, Sports catalyst & performance exhaust, fuel pump upgrades, Ported and polished head, .

Typical stage 3 mods often include: Competition cam, Engine balancing & blueprinting, Twin charging conversions, Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (pistons/head/valves)

The N14 engines respond well to mods and we're pleased to see that there are quite a few choices of parts and tuning parts around.

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

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and 15% on NA (naturally aspirated) 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

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.

NA (naturally aspirated) 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 Mods for the N14

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 is the answer. This keeps the car road legal and will flow much better due to it's higher internal surface area and design, so has the added benefit of keeping your car road legal. The alternative decat should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars..

Weakspots and problem areas on the N14

The N14 engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Timing Chain and Timing Chain Tensioner:

Chain tensioner & Chain stretching can be a problem, but the key is to change it at the correct interval. This can lead to timing chain noise, reduced performance, and, in severe cases, engine damage.

Failure to do so will push out the engine timing and kill the catalysts among other issues. There was a revised tensioner design which has proved more reliable and offers a wider margin of stretch to accommodate a loosening chain.

Premature wear of the timing chain and issues with the timing chain tensioner have been prevalent in N14 engines.

Turbocharger and Waste Gate Problems:

Turbocharger failures and wastegate rattle issues have been reported. These problems can result in a loss of power, diminished boost, and the need for costly repairs or replacements

High-Pressure Fuel Pump (HPFP) Issues:

Some N14 engines have experienced problems with the high-pressure fuel pump, leading to hard starting, misfires, or poor idling.

Oil Leaks:

Oil leaks, particularly from the valve cover gasket, have been reported. This can result in oil consumption and the need for gasket replacements.

Water Pump and Thermostat Failures:

Failures in the water pump and thermostat have been documented. This can lead to engine overheating and associated issues.

Turbo Oil Line Leaks:

Leaks in the turbo oil lines have been a problem, leading to reduced oil pressure, turbocharger damage, and potential engine issues.

Engine Mounts:

Premature wear and failure of engine mounts have been reported by some N14 owners.

When engine mounts are compromised, you may experience the following symptoms:

  • Increased vibration or shaking in the cabin, especially when the engine is running.
  • Unusual noises, such as clunking or banging, when the vehicle is in motion.
  • Misalignment issues that can result in problems with the transmission or exhaust system.
  • Reduced handling and stability of the vehicle.

Excessive wear or physical damage can cause engine mounts to crack or break. This can result in the engine not being properly secured, leading to misalignment issues and potential damage to other components.

Things to watch out for.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

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.

If you would like to know more, or just get some friendly advice 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.

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One Response to “N14 Tuning”

  1. G.T. says:

    The article are very interesting and easy to understand unlike my writing that does need an interpreter .
    Thank you for you help so far soon I ll be getting on with the forum .
    Your sincerely
    G.T.

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