BMW F20 F21 Tuning

"All you need to know about performance parts and tuning the BMW F20 F21 engine!"

As many of our forum members and readers have emailed us about the F20 F21 and recommendations on how to modify one, so this feature has been assembled to cover the primary areas which make for improvement and tuning success on this great car.

We will look at the range of engines, the best mods for the F20 and F21, and look at some tuning problems and pitfalls.

Here we review F20 F21 tuning and outline the best mods that work. BMW F20 F21 are awesome to work on and with carefully picked uprated parts like ECU maps, turbo kits and camshafts you will dramatically increase your driving pleasure.

If you have a BMW F20 or F21 and are looking for modifications to improve the performance of your car, here are some of the most vital upgrades:

History of the F20 F21

The second generation of the BMW 1 series is comprised of the F20 and F21 models. The F20 vehicles were launched with five doors whereas the F21 models were three-door cars. It replaced the E81 series of cars (E81 E82 E87 & E88).

Let's discuss these models in-depth to learn more about them, and then we'll go over the modifications that can greatly improve their performance.

BMW F20

The cars were presented in three different durations which were as under: 2011 to 2015, 2015 to 2017, and 2017 to 2019.

As the vehicles from each period were distinct, let's get into the specifics based on their epochs. 2011 to 2015 In these years the BMW F20 was offered in a total of 22 different variants which included 10 gasoline and 12 diesel engines.

Power Range 2011 to 2015

The gasoline cars had powers in between the range of 102 hp and 320 hp whereas the diesel variants ranged in power from 95 hp to 218 hp. In this era, the M135i xDrive 8AT was the vehicle to get as it had an impressive 0 to 60 mph time of 4.7 seconds. 2015 to 2017

The F20 received a facelift in 2015 which introduced several features such as rain sensors and automatic climate control.

During these years, the cars were offered in 13 gasoline and 10 diesel variants.

Gasolene:

Diesel:

Gasolene engine specs

114i

  • 101hp @4000rpm 180Nm 133lbft @1100-3900rpm
    2012-2015 1.6 L N13 inline-4

116i

  • 134hp @4400-6450rpm 220Nm 162lbft @1350-4300rpm
    2012-2015 1.6 L N13 inline-4
  • 107hp @4500-6000rpm 180Nm 133lbft @1250-3900rpm
    2015-2019 1.5 L B38 inline-3

118i

  • 168hp @4800-6450rpm 250Nm 184lbft @1500-4500rpm
    2012-2015 1.6 L N13 inline-4
  • 134hp @4000-6000rpm220Nm 162lbft @1250-4000rpm
    2015-2019 1.5 L B38 inline-3

120i

  • 130 kW 174hp @4800-6450rpm 250 N⋅m 184 lb⋅ft@1350-4500rpm
  • 2012-2015 1.6 L N13 inline-4
  • 181hp @5000rpm 290Nm 214lbft @1350-4250rpm
    2016-2019 2.0 L B48 inline-4

125i

  • 215hp @5000rpm 310Nm 229lbft @1350-4800rpm
    2012-2015 2.0 L N20 inline-4
  • 221hp @5200rpm 310Nm 229lbft @1400-5000rpm
    2016-2019 2.0 L B48 inline-4

M135i

  • 315hp @5800-6400rpm 450Nm 332lbft @1300-4500rpm
    2012-2015 3.0 L N55 inline-6
  • 322hp @5800-6400rpm 450Nm 332lbft @1300-4500rpm
    2015-2016 3.0 L N55 inline-6

M140i

  • 250 kW 335hp @5500rpm 500 N⋅m 369 lb⋅ft@1520-4500rpm
    2016-2019 3.0 L B58 inline-6

Diesel

114d

  • 94hp @4000rpm 235Nm 173lbft @1500-2750rpm
    2012-2015 1.6 L N47 inline-4
  • 95hp @4000rpm 240Nm 177lbft @1500-2750rpm
    2015-2019 1.5 L B37 inline-3

116d

  • 114hp @4000rpm 260Nm 192lbft @1750-2500rpm
    2011-2015 2.0 L N47 inline-4
  • 114hp @4000rpm 260Nm 192lbft @1750-2500rpm
    2012-2015 1.6 L N47 inline-4
  • 114hp @4000rpm 270Nm 199lbft @1750-2250rpm
    2015-2019 1.5 L B37 inline-3

118d

  • 141hp @4000rpm 320Nm 236lbft @1750-2500rpm
    2011-2015 2.0 L N47 inline-4
  • 150hp @4000rpm 350Nm 258lbft @1750-2500rpm
    2015-2019 2.0 L B47 inline-4

120d

  • 181hp @4000rpm 380Nm 280lbft @1750-2750rpm
    2011-2015 2.0 L N47 inline-4
  • 188hp @4000rpm 400Nm 295lbft @1750-2500rpm
    2015-2019 2.0 L B47 inline-4

125d

  • 215hp @4400rpm 450Nm 332lbft @1500-2500rpm
    2012-2015 2.0 L N47 inline-4
  • 221hp @4400rpm 450Nm 332lbft @1500-3000rpm
    2015-2019 2.0 L B47 inline-4

Power Range  2015 to 2017

The gasoline cars had power between 109 hp and 340 hp whereas the diesel versions of the car had power figures between 116 hp and 224 hp. The M140i xDrive 8AT was the quickest vehicle with 0 to 60 mph time of 4.4 seconds. 2017 to 2019

Another facelift known as Life Cycle Impulse or LCI was introduced in 2017.

Power Range 2017 to 2019

In these years the gasoline versions of the cars had power between 109 hp and 340 hp whereas the diesel variants ranged in power from 116 hp and 224 hp.

It is worth noting that these were the same numbers as featured by the vehicles before the LCI facelift.

However, it is pertinent to highlight that the diesel version vehicles were much slower than the gasoline ones as the top tier diesel variant had 0 to 60 mph of 6.3 seconds whereas the top tier gasoline version known as M140i xDrive 8AT did the same in 4.4 seconds.

A simple remap will address this imbalance, and many have asserted that BMW detuned the Diesels so they could sell the Gasolene variants because a Diesel offering more power and better fuel economy was a dead cert winner when people were drawing up their shortlist.

BMW F21

The F21 cars were offered in the following periods: 2012 to 2015;  2015 to 2017.

2012 to 2015

The gasoline version F21 cars in this era had power ranging between 101 hp and 320 hp.

The diesel versions had power in the range of 95 hp to 218 hp. The M135i 8AT xDrive had a 0 to 60 time of 4.7 seconds and was the quickest F21 between 2012 and 2015.

2015 to 2017

Similar to F20, the F21 also underwent a facelift in 2015.

The cars in this era had no less than 13 gasoline and 10 diesel engines.

The powers of the vehicles were as follows:

  • Gasoline: 109 hp to 340 hp;
  • Diesel: 116 hp to 224 hp.

The quickest car was the M140i xDrive 8AT with a 0 to 60 time of 4.4 seconds.

Best F20 F21 parts

The ultimate F20 F21 tuning mods on an engine are sensibly the ones that give the best value for money.

We won't be swayed by popular F20 F21 tuning mods, they need to be cost effective.

Suspension Upgrades

We found that most F20 F21 factory suspension setups need tweaking, a few degrees of toe (set some toe out to improve cornering or use toe in for better stability) and you only need around 1 to 2 degrees, and a little negative camber will dramatically enhance your cornering and handling.

Sort out those worn bushes too, the polyeurothane upgrades are a popular choice, but don't get too hard a compound, or you'll suffer from excessive vibration and everything will be too tight.

We suggest that you fit motorsport suspension and lower the car by 30mm - 35 mm. Larger drops require arch work - especially on models already equipped with performance suspension.

Suspension is pivotal to a car's handling, so no car modification is complete without a decent upgraded suspension. The following suspension upgrade options exist for the BMW F20 and F21:

  • Suspension Kits;
  • Coil-Over Kits;
  • Anti-Roll Bars;
  • Lowering Springs;
  • Strut Braces.

Performance handling kits are also high in demand. One such example is the Strange Eye Mount Lightweight Strut Package.

Parts like these are effective for drag racing and high-performance applications.

Make sure that such parts have forged Aluminum bodies and stainless steel spindles so that they are not only lightweight but also durable enough to withstand the test of time and meet your requirements.

F20 F21 Brake Upgrades

A fast car is unusable unless it can be properly controlled, and brakes play a critical role in putting the driver in charge. Some of the factors to consider when selecting brake kits are performance, value for money, and ease of installation.

For greatly improved braking add better quality pads and match this with larger brake discs.

Note that motorsport pads can grind and will have to be hot before they start to work.

On a road car the brakes are occasionally used so won't stop you as well so source friction pads which have a low working temperature.

There are several brake kits available on the market that are specifically designed for road racing and circuit use.

Yellow Speed Racing's Ultra Grand Drilled Big Brake Kit is one such example.

Such high-end parts feature forged billet aluminum calipers that have an antirust coating to increase their life. Many brands offer diamond slotted and cross-drilled rotors which enhance the stopping power and performance of brakes.

F20 F21 Camshaft Upgrades

After the intake and exhaust systems of your BMW F20/21 have been upgraded, you might also want to go for a camshaft upgrade because the stock camshaft is designed to work with factory fitted intake and exhaust systems and with other mods you can really maximize your gains with the correct camshaft profile.

The power output of your vehicle can be considerably increased with camshaft upgrades but in some areas these are still hard to source, so one alternative is to get your OEM camshaft reground to a fast road profile but make sure the lift and durations are specified correctly or you'll get flat spots or the peak power in the wrong zone.

Sporty camshaft profiles raise the top end power and are better suited on petrol engines, than diesels.

We've always seen top end power gains through performance camshafts on most engines. So altering your F20 F21 camshaft will make a difference to the engine engines power but might affect your bottom end power.

Choosing a higher performance camshaft profile raises the engines power range accordingly.

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

You should ideally optimize your bhp range to your cars usage so for a car driven daily stick with a shorter duration fast road F20 F21 camshaft.

Each engine responds differently primarily due to the airflow when camshafts are fitted depending on the camshaft being more or less aggressive camshaft durations than others as unique due to manufacturing tolerances and quality variations so set your engine up on a rolling road.

The map and fuel delivery and fuel pump also will say much on the torque gains you'll get.

Extending exhaust or intake durations can alter the torque band, and on most engines there are some advantages to extending the intake or exhaust durations and valve lift.

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Best mods for your car

  1. Mapping - remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.
  6. Typical stage 1 mods often include: Intake headers, Panel air filters, Drilled & smoothed airbox, Sports exhaust manifold, Fast road camshaft, Remaps/piggy back ECU.

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

    Typical stage 3 mods often include: Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Competition cam.

    Review your options and then find your upgrades and set yourself a power target to save yourself from expensive mistakes.

    ECU Mapping Improvements for the F20 F21

    ECU mapping allows a tuner to fully realize the full potential of all the modifications you've fitted to your F20 F21.

    (Sometimes remapping the ECU is not an option, so an aftermarket ECU is the route to take, and most of these exceed the specs and performance of your factory ECU's but ensure it has knock protection and that you get it correctly setup.)

    It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved usually rely on the modifications you've carried out and the condition of your engine.

    ECU Remapping ECU remapping is a popular technique in which the stock ECU is reprogrammed to increase the performance figures.

    Numerous companies perform ECU remapping; however, selecting the best option is critical because desired results can only be obtained if the remapping is performed by a professional.

    Several companies including AC Schnitzer and TDI Tuning offer plug and play devices that consist of additional (programmed) control units to increase the power of your BMW F20/21 by at least 20%, they are a good option for a simple power upgrade by post.

    Vehicle specific wiring harnesses with original plug connections ensure that the devices can be easily used. Although more power can be easily obtained using such performance upgrades, many companies including AC Schnitzer prefer to adopt a more durable approach to safeguard the longevity of vehicle components.

    In case the M135i 320 is remapped, the car’s stock 320 bhp can be increased to 390 bhp a 70hp increase is certainly a significant power gain.

    The torque can be raised  from 331 lbft to 443 lbft. Several companies offer their ECU remapping services in stages so that fans can choose the ones that meet their needs and wants.

    We strongly recommend you get the remap setup on a rolling road, to fully realize the power gains from all the mods you've done.

    Air Flow improvements on the F20 F21

    Feeding fuel and air into each cylinder is the aim to any engine tuning project. Contrary to popular belief there is often a small if any power gain to be had by fitting an induction kit, they only become beneficial and are recommended after you boost the engines power to the point where the standard air intake box cannot cope!

    Intakes increase the amount of air supplied to the engine and thus result in better performance figures.

    A cold air intake system like the aFe Magnum Force Stage 2 Track Series Aluminum Black Carbon Fiber replaces the stock intake system and thus offers an efficiently contoured less obstructive intake tube and a larger high flow air filter.

    The result is that greater quantities of dense cool air are supplied to the engine which boosts horsepower and torque figures due to increased combustion.

    Structure and flow characteristics of the Air Intake manifolds can make a large improvement to fuel delivery on the F20 F21.

    I usually find headers are improved through an upgrade, although some car makers provide reasonably good headers.

    Adding a F20 F21 big valve conversion, doing a bit of F20 F21 port enlargement and head flowing will also raise torque, this will give you raising the torque increase on other parts.

    F20 F21 Turbo upgrades

    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 F20 F21

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

    If your car has a turbocharger you'll notice that upgrades are giving better power gains and you'll see that turbo engines already contain many forged and stronger components.

    However most engines will need better parts at higher power limits. We recommend you find these restrictions and fit higher quality crank and pistons to utilize the power.

    It's not unheard of drivers spending loads on turbocharger upgrades on the F20 F21 only to watch the F20 F21 throw a rod on its first outing after it's used on the roads.

    Larger upgraded turbochargers commonly experience a bottom end lag, and smaller turbochargers spool up much more quickly but do not have the top end bhp gains.

    Thankfully the world of turbo units is always developing and we now see variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end bhp.

    Twin scroll turbo units divert the exhaust gases into two channels and push these at differently profiled vanes in the turbo. They also boost the scavenging effect of the engine.

    F20 F21 Intercoolers

    An aftermarket intercooler is another great option for a modified car. The Wagner Tuning EVO 2 Competition Intercooler Kit is a great example of a highly effective part that plays a pivotal role in increasing the car’s performance.

    Such parts allow up to a 70% increase in the frontal area and 90% more volume than the stock intercooler. Besides this, the aftermarket intercoolers get rid of any bottlenecks in the OEM ones to ensure better operation and thus result in increased performance.

    A note on air flow sensors

    You'll commonly see there's a limit in the air flow sensor AFM/MAP on the F20 F21 when a lot 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 was restricting power at a much lower level.

    Adding a supercharger or additional turbo or larger turbo will make large bhp and torque gains, although more complex to setup. We have this feature on twinchargers if you want to read more.

    F20 F21 Fuelling Upgrades

    As a result of the increased power and acceleration, a modified car's fuel requirements are significantly higher than those of an unmodified vehicle. Therefore, the demand for fuel-related modifications grows significantly.

    It is important to over specify your injector capacity. So as a rule of thumb add 20% to the flow rate when fitting an injector, this allows for injector deterioration and provides a little spare capacity should the engine require more fuel.

    We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

    F20 F21 Performance Exhausts

    You only need to to boost your exhaust if the existing exhaust is creating a restriction.

    On most factory exhausts you'll see your flow rate is good even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust. Performance exhausts are designed to reduce the backpressure and thus result in greater performance.

    These exhausts are made up of lighter material which sheds the weight of the car while also improving the overall sound of your modified BMW F20/21. If you want extremely aggressive sound, we recommend going for the Flowmaster Super 10 Series Delta Flow Exhaust Muffler made up of stainless steel which comes with a limited lifetime warranty.

    Sports exhausts equal out the flow of air through the engine.

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

    Usual exhaust restrictions come around the catalyst and filters installed, so adding a better flowing performance aftermarket version will improve airflow, and rather than doing an illegal test pipe mod, will keep the car road legal. We note that performance catalysts and filters perform comparably to test pipe mod and have the added benefit of keeping your car street legal, as decat or catalyst removal is not a street legal modification.

    Weak spots, Issues & problem areas on the F20 F21

    The F20 F21 engines are fairly reliable as long as they are looked after and serviced.

    Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a very common problem on direct injection engines but should be looked out for on all engines. We have tips on removing carbon To minimize this risk only use quality fuel and don't short journeys.

    Common Issues With The BMW F20/21

    Electrical problems

    A common issue with these cars is related to their electrical system. In such cases, the power to the engine is cut off completely and even the external lights get turned off. The main cable, which supplies power to the car's distribution box, is the source of this problem. When this happens, the lights in the instrument cluster begin to flicker. Check the PDC unit in the boot is dry and that the filters in the wheel wells have been fitted the correct way up. A damp PDC will fire off all kinds of warning lights.

    Traction control (DTC ) Warning light comes on, which usually means the traction control unit needs replacing.

    Coil pack problems

    Coil pack issues are quite common, and the fault identifies itself as rough running, a petrol smell inside the car in some cases and erratic engine temperature. You can also experience engine vibration, loss of power or end up in limp home mode. Replacing the coil pack will rectify the fault.

    Idling problems

    Idling from a cold start can be an issue, if this is the case make sure the ECU is updated to the latest version which should address this issue in the software.

    Timing chain issues

    The N47 engine had an issue with timing chains, so if it starts making a grinding noise get it checked out ASAP or you'll need to replace the engine. We would recommend that you get the timing chain checked at your next service as a precaution.

    Other build quality problems

    A common problem was that the driver's seat didn't latch properly, allowing the seat to fold in the event of a collision or sudden braking. Another issue with the F20 and F21 series cars was gas leakage from the exhaust gas recirculation.

    Regular oil changes are highly recommended on the F20 F21, and more importantly so when the car is tuned, and will help extend the life and reliability of the engine.

    If you want to know more, or just get tips on Tuning your F20 F21 engine please join us in our friendly forum where you can discuss F20 F21 tuning options in more detail with our F20 F21 owners. It would also be worth reading our unbiased BMW tuning articles to get insights into each modification and how effective they will be.

    Please help us improve these tips by sending us your feedback in the comments box below.

    We love hearing what our members have got up to and which modifications work best for them on each model of car. Comments are used to improve the accuracy of these F20 F21 articles which are continually updated.

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