Tuning the BMW B47

"Comprehensive guide to tuning the BMW B47 engine!"

The BMW B47 are popular engines and with the ultimate sports upgrades like remapping, turbo kits and camshafts you will dramatically improve your driving pleasure.

TorqueCars will review and look at B47 tuning and provide tips on the ultimate modifications for your car.

Just because particular tuning parts are popular with B47 owners it doesn't mean it is good, we shall concentrate) on the top tuning parts that will give your B47 the biggest power gain return for your cash.

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.

NB: Fast road cams tend to increase the torque throughout the rev band, you might lose a little bottom end bhp but your higher rpm power will be higher.

Motorsport and race cams, increase the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a daily driver you need to match your engines power to your typical driving style.

I'd be amazed if you have found a B47 Motorsport cam is a pleasure to live with when driving around busy urban areas.

Some B47 engines respond better to more aggressive cam durations so set your engine up on a rolling road.

The engine timing and fuelling also have an effect on the torque gains you'll get.

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.

Stage 1 modifications: Sports exhaust manifold, Fast road camshaft, Remaps/piggy back ECU, Drilled & smoothed airbox, Intake headers, Panel air filters.

Stage 2 modifications: Sports catalyst & performance exhaust, fuel pump upgrades, high flow fuel injectors, Fast road cam, Ported and polished head, induction kit.

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

Carefully think through your options and then acquire your upgrades and set yourself a power target to save yourself from expensive mistakes.

A remap should help to release the full potential of all the modifications you've fitted to your B47.

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

It is the whole point to any engine modification project to pull more air into your B47

Intake transmit the air during the suck phase from the filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

The size of bore and shape and rate of flow of the Intake can make a noticeable change to fuel atomisation and engine efficiency on the B47.

It's not uncommon that headers are in desperate need of performance upgrades, although some car makers provide reasonably good headers.

Increasing the B47 valve size, doing a bit of port matching and head flowing will also increase performance, & more importantly will allow you to get raising the performance increase on other upgrades.

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 B47

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

If your car is fitted with a turbocharger parts are going to net you a larger power gain and you'll see that turbocharged engines use stronger components.

There are tuning limits for every engine, with some being extremely strong and some only able to handle stock power

It is important to find these limitations and upgrade to higher quality components to survive the power.

We've seen people spending a loads of money on turbocharger upgrades on the B47 only to suffer the humiliation of seeing the car catastrophically fail on it's first outing after it's used on the roads.

Larger capacity turbos often suffer a bottom end lag, and small turbos spool up more quickly but won't have the high rpm engines power gains.

Thankfully the world of turbos is always increasing and we commonly find variable vane turbos, permitting the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust gases into 2 channels and feed these at differently profiled vanes in the turbo charger. They also boost the scavenging effect of the engine.

You'll commonly see there is a limitation in the air flow sensor (AFM/MAF/MAP) on the B47 when a lot more air is being pulled into the engine.

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

Adding a supercharger or additional turbo will make large performance gains, although more difficult to install. We have this in depth look at twinchargers if you want to read more.

Fuelling upgrades and mods

When you increase the bhp and torque you will need to increase to the fuel delivery.

More bhp and torque needs more fuel. We would recommend you to be generous with your flow rate on the injectors.

The rule of thumb is to add another 20% when specifying an injector, which takes into account 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.

Exhaust upgrades and mods

You only need to to upgrade your exhaust if your exhaust is actually creating a flow problem.

On most factory exhausts you should find that the flow rate is still ok 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 out of the engine but do not go too large or you could will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.

Common exhaust restrictions can be located the catalysts installed, so adding a freer flowing high performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the B47

The B47D20 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the B47D20, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

DPF can be an issue on short journeys and lots of cold starts, so read our guide on cleaning a DPF to keep it in good condition.

For more information on Tuning your B47D20 engine please join us in our friendly forum where you can discuss tuning options in more detail with our tuning articles to get a full grasp of the benefits and drawbacks of each modification.

History of the Engine

The fuel pressure is rated to around 2000bar - typical for a direct injection diesel engine and turbos are the twin scroll variety which have variable geometry inlets.

We also see double VANOS used on the B47 which gives a nice power band. Each cylinder has 4 valves and are designed to warm up very quickly, helping reduce emissions and particulate filter build up.

B47D20 (85 kW version)

114  hp @ 4,000 rpm 270 Nm (199 lbft at 1,250–2,750 rpm

  • 2015–2019 F30/F31 316d
  • 2020–present G20 316d

B47D20 (110 kW version)

148  hp @ 5,000 rpm 236lbft-266lbft

  • 2014–2016 F10 518d
  • 2014–present F45 218d Active Tourer
  • 2015–present F20 118d
  • 2015–present F22 218d
  • 2015–present F25 X3 sDrive18d
  • 2015–2019 F30/F31/F34 318d
  • 2015–present F32/F36 418d
  • 2015–present F48 X1 sDrive18d
  • 2015–present F54 MINI Cooper D Clubman
  • 2017–present F39 X2 sDrive18d
  • 2017–present F60 MINI Cooper D Countryman
  • 2019–present G20 318d
  • 2019–present F40 118d

B47D20 (125 kW version)

168  hp @ 4,000 rpm 360 Nm (266 lbft at 1,500–2,750 rpm

  • 2015–present F56 MINI Cooper SD

B47D20 (140 kW version)

188  hp @ 4,000 rpm 400 Nm (295 lbft at 1,750–2,500 rpm

  • 2014–2016 F10/F11 520d
  • 2014–present F26 X4 sDrive20d
  • 2014–present F45 220d Active Tourer/220d Gran Tourer
  • 2015–present F20 120d
  • 2015–present F22/F23 220d
  • 2015–present F25 X3 sDrive20d/xDrive20d
  • 2015–2019 F30/F31/F34 320d
  • 2015–present F32/F36 420d
  • 2015–present F48 X1 sDrive20d
  • 2015–present F54 MINI Cooper SD Clubman
  • 2016–present G30/G31 520d
  • 2017–present F39 X2 xDrive20d
  • 2017–present F60 MINI Cooper SD Countryman
  • 2017–present G01 X3 xDrive20d
  • 2018–present G32 620d Gran Turismo
  • 2019–present G20 320d
  • 2019–present F40 120d xDrive
  • 2019–current F44 220d Gran Coupé

B47D20 (165 kW version)

221  hp @ 4,400 rpm 450 Nm (332 lbft at 1,500–3,000 rpm
202  hp @ 4,000 rpm 430 Nm (317 lbft at 1,750–3,000 rpm

  • 2015–present F20 125d
  • 2015–present F22 225d
  • 2015–2018 F30/F31/F34 325d
  • 2016–present F32/F33/F36 425d

B47D20 (170 kW version)

228  hp @ 4,400 rpm 332lbft - 369lbft

These have a clever multi stage turbo setup and fuel pressure is 2500bar.

  • 2015–2018 X5 F15 sDrive25d/xDrive25d
  • 2016–present F48 X1 xDrive25d
  • 2017–present G01 X3 xDrive25d
  • 2017–present G30/G31 525d
  • 2018–present F39 X2 xDrive25d
  • 2018–present G02 X4 xDrive25d

Tuning the BMW B47 and best B47 performance parts.

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