Guide to tuning the BMW N13 engine

"Thanks for reading our N13 engine tuning guide"

BMW needed a small and powerful engine and got together with the PSA group and produced the Prince engine.

BMW have labelled this the N13 to fit in with their naming conventions and it was fitted to the 1 and 3 series.

A revised version called N14 and N18 was later produced to suit the Mini range, and this is probably where tuning interest in these Prince derived engines started to take off.

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 N13 Engine

Jointly developed with the PSA group we have the N13 engine, a turbocharged unit available in a few power versions.

It was produced from 2011 to 2016 and was BMW's first recent 4 cylinder turbocharged petrol engine since the early 1970's

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

The Mini had an N14 and N18 version of this engine fitted.

75 kW version

  • 2012–2015 F20 114i

101 kW version

  • 2011–2015 F20 116i
  • 2012–2015 F30 316i

125 kW version

  • 2011–2015 F20 118i
  • 2012–2015 F30 320i ED

130 kW version

  • 2015-2016 F20 120i

What are the most effective N13 mods

The top tuning parts on an engine are in our opinion the ones that give the best power gain for you spend.

We won't be swayed by popular N13 tuning 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 engines power and torque output.

Fast road camshafts tend to boost the torque across the rpm range, you may sacrifice a little low down power but your top end will be higher.

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

In a car driven daily you need to match your bhp range to your preferences.

You will never have thought a Competition cam is a pleasure to live with when in heavy traffic.

Each engine responds better to more aggressive cam durations than others.

The ECU mapping and injectors and fuel pump also will say much on the bhp gains you'll make.

Longer valve durations can alter the bhp 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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How to tune your car

  1. Improve the handling

    Focus on Suspension improvements, such as coilovers and make sure the bushings are in good order and that the alignment is correct. Then focus on improving the brakes, with a big disk brake conversion kit and fast road brake pads.

  2. Remove restrictions

    Focus on the intake and exhaust with filters being the common point of restriction in a tuned car. Intercoolers may also become restrictive on turbo engines so this may also need to be uprated.

  3. Burn more fuel & air

    Increase the fuelling so it matches the air coming into the engine. The ratio is important so you need to improve the fuel pump and injectors, so the head mods, big valve conversions, fast road camshafts and forced induction upgrades extra supply of air is adequately met.

  4. Test and replace any weak parts

    Weak areas are commonly the clutch, the turbocharger and pistons and crankshaft in a highly tuned engine. Makes sure these components will cope with your power aspirations.

  5. The Tune or Remap

    A cars ECU controls the fuel, timing, spark and even the turbo in some cases, so to fully extract your gains you should remap the car last and this will fully release the power. Some cars are easy to map, and others require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project.

Modifying to Stage 1:

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

Modifying to Stage 2:

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

Modifying to Stage 3:

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

The N13 engine blocks make great tuning projects and we're happy to report there are quite a few choices of modifications and tuning parts about.

A remap will help unlock the full potential of all the parts you've done to your N13.

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

It is the whole point to any enging upgrade project to feed more air and fuel into your N13

Plenum transmit the air from the filter and allow it to be pulled into the engine and mixed with fuel.

The size of bore and shape and rate of flow of the Plenum can make a big difference to to fuel delivery on the N13.

Commonly we find the plenum chambers are improved through aftermarket tuning parts, although some OEM provide reasonably good plenum chambers.

Adding a N13 larger valve kit, doing some port work and head flowing will also increase power, and significantly will permit raising the power increase on other upgrades.

N13 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 N13

When an engine has forced induction parts are relatively easy and you'll see that turbo engines are made using more solid components.

However you'll find engines have limits

Discover these restrictions and upgrade to better pistons and crank to utilize the power.

We've seen drivers spending a a stack of money on turbocharger upgrades on the N13 only to suffer the humiliation of seeing the car go up in smoke soon after it's used in anger.

Large capacity turbo chargers tend to experience no power at low rpm, and small turbo chargers spool up really quickly but do not have the high rpm engines power gains.

In the last 10 years the choice of turbo chargers is always moving on and we commonly find variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo chargers divert the exhaust flow into two channels and feed these at differently designed vanes in the turbo. They also improve the scavenging effect of the engine.

It is not unusual that there is a restriction in the air flow sensor AFM/MAP on these engines when considerably more air is being drawn into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped power at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although harder to setup. We have a twincharger performance adding guide if you want to read more.

Fuelling

You will need to ensure that the engine is not starved of fuel so should increase the fuelling when you start extending past 20% of a bhp and torque increase.Don't forget to be generous with your flow rate on the injectors.

The accepted safe increase is to add another 20% when buying an injector, this takes into account injector deterioration and allows some spare capacity should the engine need more fuel.

N13 Exhaust

You should look to replace your exhaust if the current exhaust is creating a flow problem.

On most factory exhausts you'll find the exhaust 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 generally help improve air flow through the engine but avoid an exhaust that is too large or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

Typically exhaust restrictions can be located the emissions filters installed, so adding a higher flowing high performance alternative will help avoid this restriction.

Weak spots and problem areas on the N13

The N13 engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the N13, especially when tuned and will help extend the life and reliability of the engine.

There have been factory recalls for failing HPFP (high pressure fuel pumps) in the N13 engines.

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 N13 tuning options in more detail with our N13 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 parts work best for them on each model of car. Comments are used to improve the accuracy of these articles which are continually updated.

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