BMW F15 Tuning

"All you need to know about tuning the BMW F15 X5!"

As many of our readers have emailed us about the F15 X5 and wanted us to make recommendations on how to modify one, with a list of best mods and upgrades and how to tune it.

So we've put together this guide to cover the primary areas which make for improvement and tuning success on this great car.

F15 was the name given to the third generation of the BMW X5 that was offered from 2014 to 2018.

This SUV belonged to the premium segment and was the most sold luxury vehicle of its type. It had a unibody construction but had no low-gear and no transfer case.

We shall look into F15 tuning and summarise the greatest upgrades. BMW F15 are popular engines and with carefully chosen modified enhancements like ECU maps, turbo kits, and camshafts you will dramatically maximize your driving pleasure.

History of the F15 Engine

Different Variants

The BMW F15 was offered in 10 different options with 3 of them being gasoline, 6 diesel, and 1 hybrid model.

Gasoline Variants

The gasoline variants of the BMW F15 were as follows:

  • sDrive35i
    It had an 8-speed automatic transmission. The vehicles N55 had 300 hp and 400 Nm torque which propelled it from 0 to 62 mph in 6.4 seconds.
  • xDrive35i
    This model had a total of 306 hp and 402 Nm torque from the N55 but the acceleration from 0 to 62 mph was a bit slower i.e. 6.5 seconds.
  • xDrive50i
    This was the quickest variant of the BMW F15 with the N63 that featured a total of 450 hp and 649 Nm torque which meant that the vehicle accelerated from a standstill to 62 mph in 4.9 seconds.

Diesel Variants

The 6 diesel variants of the BMW F15 were as follows:

  • sDrive25d 8AT
    N47 with 218 hp and 450 Nm torque. The 0 to 62 mph time was 8.2 seconds;
  • xDrive25d 8AT
    N47 with 218 hp and 450 Nm torque. The 0 to 62 mph time was 8.2 seconds;
  • xDrive30d 8AT
    N57 with 258 hp and 560 Nm torque. The 0 to 62 mph time was 6.8 seconds;
  • xDrive35d 8AT
    N57 with 259 hp and 576 Nm torque. The 0 to 62 mph time was 7.1 seconds;
  • xDrive40d 8AT
    N57S with 313 hp and 630 Nm torque. The 0 to 62 mph time was 5.9 seconds;
  • xDriveM50d 8AT
    N57S with 381 hp and 740 Nm torque. The 0 to 62 mph time was 5.3 seconds.

Hybrid Variant

  • xDrive40e 8AT N20 with 313 hp and 350 Nm with a 0 to 62 mph acceleration time of 6.8 seconds.

Tuning the BMW F15 and best F15 performance parts.

Best F15 upgrades

Just because particular tuning mods are popular with F15 owners it doesn't mean it is good, we shall focus on the top tuning mods that will give your F15 the biggest power gain return for your cash.

If you are looking for modification upgrades for your BMW F15, here are some of the best options in this regard.

Please watch our video which covers the 5 principles of tuning your F15. Be sure to subscribe and support our new channel.

Best mods for your F15

  1. Mapping - F15 remapping provides the most advantage in terms of cost, aftermarket ECU upgrades, 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 are doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake Mods 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. X5 Suspension Upgrades - Fitting a more sporty Suspension kit greatly enhances your F15 road holding and cornering. Coilovers and Bushings are the usual go to mods
  5. Braking Mods - Enhancing your stopping power needs to be listed in your priority list.
  6. Forced induction upgrades - A New Turbo is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. Although one of the most costly upgrades it offers big gains.

F15 Tuning Stages

Typical stage 1 mods often include: Intake manifolds, Panel air filters, Fast road camshaft, Remaps/piggy back ECU, Sports exhaust manifold, Drilled & smoothed airbox.

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

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

Mapping the F15 engines

Performance tuners & programmers are fitted with a large number of maps (in some cases as many as 7) which means that drivers can select the map of their choice with the help of a digital user interface that provides additional control to drivers.

One such example is the RaceChip GTS Black Series Chip Tuning Box Kit which costs around $700.

ECU Remapping

ECU remapping, also known as flashing, is a method using which the ECU of your BMW F15 can be remapped.

During the remapping process, the software of the stock ECU is replaced with new files that enhance the performance of the vehicle by allowing more fuel to be delivered to the engine. This in turn increases the performance figures.

This is an effective method because automakers usually design the vehicles keeping their longevity in mind which often means that the vehicles are usually capable of generating more power and torque.

Piggybacks vs. Standalone ECUs

If you desire to get more power from your BMW F15, you have two options which are piggybacking and standalone ECUs.

What Are Piggybacks ECUs & Why Should You Use Them?

Piggybacks are small parts that are added as Plug & Play devices while keeping the stock ECU on the vehicle.

Such devices are usually much smaller than standalone units and offer a limited number of features.

But if you wish not to alter your vehicle by much, these are great options.

Piggybacks also cost considerably lesser than the standalone ECUs and the stock ECU of the vehicle doesn’t become redundant.

What Are Standalone ECUs & Why Should You Use Them?

Standalone ECUs, on the other hand, completely replace the stock ECUs and thus vehicle owners need to get rid of the factory fitted part.

While these ECUs cost much more than the piggybacks, they deliver superior performance and thus in most cases, justify their higher price.

A major disadvantage of the standalone ECUs is that several OEM features are affected and at times the size of these parts is so big that fitting them is also a problem.

Which Is The Better Option?

There is no hard and fast rule when it comes to choosing which is better out of these as the choice is dependent upon your requirements.

However, one thing is for sure that if you want to perform a wide array of performance mods on your BMW F15, getting the Standalone ECU will prove better for you.

This is true because standalone ECUs allow more options when it comes to the installation of performance modifications.

F15 Brake Upgrades

A fast car is no good without a proper controlling mechanism that can aid the drivers in stopping the vehicles whenever required.

This is why installing a proper braking upgrade is as vital as getting higher power and torque figures.

For improving the braking of your racing car, you can install one of the following parts:

  1. Brake Kits;
  2. Brake Rotors;
  3. Brake Pads;
  4. Brake Calipers;
  5. Brake Boosters

The easiest upgrade to your brakes is replacing the pads with higher-performance ones. Something from Brembo, Pagid or EBC would improve your X5's stopping power considerably before you even think about upgrading the disks..

F15 Suspension Mods

Suspension plays a pivotal role in the handling of a vehicle and thus if you want to reduce the body roll on your BMW F15 or want to lower the vehicle, as a whole, to get better performance, suspension upgrades are the way to go.

Some of the suspension modifications available for the F15 include:

  1. Coilover Kits;
  2. Lowering Kits;
  3. Handling Kits;
  4. Sway Bars;
  5. Coil Springs.

The Coilover kits are particularly useful for customers who want to easily adjust the damping as well as the ride height of their vehicles. These allow you to fine tune your X5's handling characteristics.

By lowering the center of gravity of your BMW X5, you can make it better suited for cornering and also enhance the overall appearance of the vehicle.

Improvements to the bushings

Enhancements to the bushings: Things you need to know

It is possible to connect the F15's suspension components to the chassis of the F15 using poly bushes, which are direct replacements for the rubber mounts. The rubber ones will wear out with time and need replacing anyway so why not upgrade.

Brand New OEM rubber bushings may have a major impact on the performance of your vehicle.

Because the polyurethane bushes are firmer, the ride may be a bit more harsh, but they will last longer and maintain the handling.

They may also speed up the degradation of other suspension parts due to the increased vibration and play.

With a new set of polyeyurothane bushes, the excessive play associated with rubber bushings may be reduced.

You may struggle to find a full set of polyeyurothane bushes, but most stores have the primary mounts available. Often, custom F15 poly bushes may be manufactured to your requirements.

Many people believe that a 90mm lower F15 suspension kit from a modified car part shop would be ideal. However, this is not the case - suspension design and setup is quite complex.

Vendors may assert that their F15 suspension kits are compatible with any or all of the F15 model years.

To adequately support a diverse variety of vehicles, the "compromized"approach is obviously a mistake as engine weights and equipment trim levels all affect the cars handling characteristics.

How low should you go on the F15?

According to TorqueCars research and testing, the maximum amount of suspension drop for most road vehicles is 28 - 36 millimetres, whereas versions that come with lowered sporty suspension already have a maximum suspension drop of 17 millimetres.

Tolerances may be greatly lowered by altering the diameter of the wheels. Lowering a vehicle, even with 17-inch wheels and stock suspension, will create several issues.

While the fact that the F15 being lower allows for less air to travel underneath it may aid in stability, the ultimate goal should always be to enhance handling. When lowering the springs, it is critical to use the proper shocks that match all round.

Fully adjustable suspension allows you to fine tune the handling of you F15 greatly improving your drive.

Fitting better brake discs and better high performance brake pads can make for radically improved braking.

Bear in mind that some performance brake pads can be noisier and will have to be hot before they start to work.

On your regular commute to work the brakes are only applied now and then and won't be as effective at slowing you up so source brake pads which work well in daily use.

F15 Camshaft Upgrades

Getting a fast road cam will come into their own at upper RPM range power and are better suited on petrol engines, than diesels. In most cases, you will see peak power increases through performance camshafts on most engines

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large power band gains are on offer for cam upgrades.

Fast road cams normally push up the torque across the rpm range, you might lose a little low down power but top end will be better.

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

A Motorsport camshaft is not great driving around busy urban areas.

You should ideally match your torque band to your usage of the car so for a car driven daily stick with a fast road F15 camshaft

Some F15 engines respond differently due to the head and flow characteristics when cams are fitted depending on the cam being more extreme cam durations and cam profile as unique due to manufacturing tolerances and quality variations so check your engine on a rolling road.

The map and fuelling and fuel pump and injectors also have a large bearing on the bhp gains you'll hit.

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

Plan your options and then buy your modifications and set yourself a power target to save yourself from expensive mistakes.

ECU Mapping Improvements for the F15

A remap helps release the full potential of all the tuning mods you've done to your F15.

(Sometimes remapping the ECU is not an option, so an aftermarket ECU is a route to take, and many of these will outperform factory ECU's but ensure it has knock protection and that you get it installed right.)

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but your results usually depend much on the tuning mods you've carried out and the condition of your engine.

Air Flow improvements on the F15

It is vital to any tuning task to feed air into each cylinder efficiently.

Your Intake takes the air from the filter and allows it to be sucked into the engine cylinders, any restrictions in this will sap your performance effectively capping your X5's performance.

Most air filters and induction mods will only remove a restriction rather than adding power so on a stock x5 with no other mods you are unlikely to see much of a power gain at all. However if you've tuned your F15 you may well be experiencing a restriction so an upgrade here makes a lot of sense.

Air Induction Systems

The first and most important upgrade of a vehicle is related to its air induction system and the case is no different for the BMW F15.

Air induction systems are important because when internal combustion engines get more air they can produce more horsepower and torque due to increased combustion rate.

The Magnum Force Stage 2 Cold Air Intake System is a great upgrade in this regard which comes with everything that is required for the installation of this high-performance part. It costs around $550 £400 but the power gain justifies the relatively high price tag.

Furthermore, what makes the high-end air induction systems so good is that they can be normally installed in 40 to 45 minutes whereas the performance upgrade they deliver is exceptional.

Design and flow characteristics of the Intake manifold can make a large difference to to fuel mixing and power on the F15.

Many mass produced engine intake manifold are in dire need of aftermarket tuning parts, although some car makers provide decently flowing intake manifold.

Increasing valve sizes on F15, getting F15 port enlargement and head flowing will also increase bhp, and as an added benefit will afford you a greater bhp increase on other tuning parts.

F15 Turbo upgrades

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

When your motor is fitted with a turbo parts are going to net you a larger power gain and most turbo charged engines are built using better components.

There are common areas of failure for every engine, with some being over specified and some only just able to handle stock power. We recommend you find these limitations and fit stronger pistons, crank and engine components to utilize the power.

Turbochargers

Turbochargers use the exhaust gases produced by the engine to run the turbine and in turn, the compressor is automatically rotated.

This mechanism draws in a greater amount of fresh, oxygen-enriched, air to the engine and as a result of this, the air & fuel mixture becomes more saturated. The increased combustion, therefore, results in higher power & torque.

A good quality turbocharger like the Dinan Turbo Upgrade costs around $2000 £1700 and enhances the BMW F15’s power by 101 hp and the torque by 117 Nm which are impressive figures.

Another great example is the BorgWarner Airwerks Super Core Turbocharger that costs $1150 and comes with a 12-month warranty that is coupled with BorgWarner’s heritage of more than a century.

Big turbo chargers often suffer low end lag, and little turbo chargers spool up quickly but won't have the top end engines power gains.

In recent times the range of turbo chargers is always developing and we are seeing variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

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

It is not unusual that there is a restriction in the air flow sensor MAP/MAF/AFM on the F15 when loads more air is being sucked into the engine.

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

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

F15 Fuelling Upgrades

You will need to ensure that the engine is not starved of fuel so will need to ramp up the fuelling when you start extending past 20% of a bhp and torque increase. Boosting the fuel pressure can improve the acceleration responsiveness.We strongly recommend you to be generous with your injectors flow rate.

Some of the fuel system upgrades you can perform on the BMW X5 include but are not limited to:

  • Fuel Pumps;
  • Fuel Filters;
  • Fuel Pumps;
  • Water Methanol Injectors;
  • Nitrous Oxide Systems;
  • Fuel Injectors & Rails;
  • Carburettors;
  • Intake Manifold;
  • Spark Plugs.

By adding an air induction system to your X5, you might be able to get more air to the engine but unless you are able to provide more fuel to the engine, the air & fuel mixture won’t be able to generate the additional power.

This is where the need for an upgraded fuel pump and fuel injectors comes into action as these parts ensure that the engine gets the required amount of fuel and thus give the results for which the air induction systems are installed.

The Bosch Direct Injection High-Pressure Fuel Pump is a good option in this regard and with a nominal price of $125, it is a must-have for your BMW F15.

As a rule of thumb add 20% to the flow rate when specifying an injector, this accounts for injector deterioration and provides some 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.

F15 Performance Exhausts

You may need to upgrade your exhaust if the current exhaust is creating a restriction in flow.

On most factory exhausts you should find that the flow rate is still fine even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Some of the exhaust system upgrades that can be installed on the BMW F15 include:

  1. Headers;
  2. Catalytic converters;
  3. Mufflers;
  4. Exhaust Tips;
  5. Emission Controls.

When a vehicle produces more power, as a result of a higher combustion rate, the exhaust gases must also leave the vehicle quickly.

This is vital because, in the absence of a proper exhaust system, the temperature of the engine will go on increasing which affects the performance.

A performance exhaust also prevents the backfiring of gases and thus keeps the engine from running properly for long durations.

Besides this, racing car fans install performance exhaust systems to get aggressive exhaust sound which is considered an integral part of a performance modification.

If you are looking for an exhaust system with an aggressive sound, the aFe Mach Force XP SS Cat-Back Exhaust System with Quad Rear Exit is a great option.

Although the system costs around $3500, still when you get it going, the results are phenomenal.

Sports exhausts can usually air flow from the engine but avoid an exhaust that is too big or you may end up stuffing up your flow rate. Generally speaking you should stick to around 1.5 to 2.5 inches for best results.

Typically exhaust restrictions are traced to the filters installed, so adding a better flowing race aftermarket version unlocks that lost power, and instead of doing an illegal decat, will keep the car road legal. Please note that performance catalyst perform comparably to catless exhaust mods and have the added benefit of keeping your car street legal, as decat or catalyst removal is not a street-legal modification.

F15 Intercooler upgrades

An intercooler is another integral performance upgrade for your BMW F15. The stock intercooler is good enough for normal operation with the parts fitted by the automaker.

However, when you take your vehicle to the next level modification, the need for a serious intercooler becomes vital.

This is because an intercooler ensures the provision of cool dense air to the engine which can be used for enhancing the performance of the vehicle.

One good example of a great intercooler is the Wagner Tuning Competition Front Mount Air to Air Intercooler Kit which costs around $1100.

Weak spots, Issues & problem areas on the F15

The F15 engines are pretty solid and give little trouble as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves will cause flat spots and loss of power, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon Avoid short journeys and use good quality fuel.

Regular oil changes are vital on the F15, especially when tuned and will help prolong the life of the engine.

If you want to know more, or just get some friendly advice on Tuning your F15 engine please join us in our friendly forum where you can discuss F15 tuning options in more detail with our F15 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 to hear what our visitors have got up to and which upgrades work best for them on each model of car. We use your comments and feedback to improve the accuracy of these F15 tuning guides which get regular updates and revisions.

Check out my YouTube channel, we're regularly adding new content...


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