Tuning the BMW N55B30

"Comprehensive guide to tuning the BMW N55B30 engine!"

TorqueCars will examine the options for your N55B30 tuning and outline the premier modifications. BMW N55B30 make awesome project engines and with the right enhancements like a remap, turbo kits and camshafts you will enhance your driving enjoyment.

When talking about the best ultimate for your N55B30 engine, we are going to concentrate on the parts that give the best value for money.

Significant gains on the N55B30 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.

NB: Fast road cams tend to increase the power through the rpm band, you might lose a little low down torque but the high end rpm power will be lifted.

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

On a daily driver must carefully try to optimize your engines power to your typical driving style.

You'll never have found a N55B30 Motorsport and race camshaft is a pleasure to live with when in heavy traffic.

Different N55B30 engines respond better to more aggressive camshaft durations so set your engine up on a rolling road.

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

Altering 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.

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

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

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

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

A remap allows a tuner to fully realize the full potential of all the tuning parts you've fitted to your N55B30.

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

Feeding more air and fuel into your N55B30 is the whole point to any engine performance tuning task.

Air Intake manifolds transmit the air from the air cleaner and allow it to be sucked into the engine cylinders.

The size of bore and shape and flow characteristics of the Plenum can make a substantial change to fuel mixing and power on the N55B30.

We often see air intake manifolds are in desperate need of performance upgrades, although a few OEM provide reasonably good air intake manifolds.

Larger N55B30 valves, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also improve power, and significantly will give you a better power increase on other parts.

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 N55B30

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 modifications are going to net you a larger power gain and we find turbo charged engines are built with many forged and stronger components.

However you'll find engines have limits

See where you'll find these limitations and upgrade to forged components to handle the power.

It's not unheard of guys spending a a stack of money on turbo upgrades on the N55B30 only to suffer the humiliation of seeing the N55B30 literally blow up soon after it's completed.

Bigger upgraded turbo units commonly experience no power at low rpm, and smaller turbo units spool up really quickly but do not have the high rpm bhp gains.

Thanks to progress the range of turbos is always improving and we are seeing variable vane turbos, where the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbos divert the exhaust flow into a couple of channels and feed these at differently angled vanes in the turbo charger. They also increase the scavenging effect of the engine.

It is not unusual that there's a limit in the air flow sensor MAF/MAP on the N55B30 when loads more air is being pulled into the engine.

You'll see that 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 will make large torque gains, although more complex to install. We have this feature on twinchargers if you want to read more.

Fuelling upgrades and mods

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

The accepted safe increase is to add 20% capacity when fitting an injector, this accounts for injector deterioration and provides a bit of spare capacity should the engine need 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 uprate your exhaust if the existing exhaust is creating a flow problem.

On most factory exhausts you'll see your flow rate is still good 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 equal out the flow of air through the engine.

But if the exhaust is too big, ie: it's over 2.5 inches bore, you will lose a lot of the flow rate and end up lacking power and torque.

Usual exhaust restrictions can be traced to the catalyst and filters installed, so adding a better flowing performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the N55B30

The N55 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the N55, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

Oil consumption issues have been noted, due to a PCV crank case valve.

Injector failure can cause a misfire, and vibration, and we recommend these are replaced every 50,000 miles.

History of the N55 Engine

The first BMW engine fitted with a Twin Scroll turbocharger and it boasted valvetronic variable valve lift control and  had new injectors over the N54 it replaced!

Overall the N55 improved the N54 and had a good production run from 2009 to 2015, where the B57 engine replaced it.

Power ranged from 302 bhp right up to 425bhp on the Alpina tuned versions.

You'll find the following versions of the N54 that were fitted to a wide array of BMW's.


  • 2009–2017 F10/F11/F07 535i
  • 2010-2013 E90/E91/E92/E93 335i
  • 2010-2013 E82/E88 135i
  • 2010–2017 F25 X3 xDrive35i
  • 2011-2013 E70 X5 xDrive 35i
  • 2011–2015 F30/F31 335i
  • 2011–2014 E71 X6 xDrive 35i
  • 2012–2015 E84 X1 xDrive35i
  • 2013–2016 F32/F33/F36 435i
  • 2014–2018 F15 X5 xDrive 35i
  • 2014–2019 F16 X6 xDrive35i
  • 2014–2016 F26 X4 xDrive 35i

Alpina BiTurbo

  • 2013–2017 Alpina F30 B3 Bi-Turbo
  • 2013–2017 Alpina F33/F34 B4 Bi-Turbo
  • 2017– Alpina F30/F31 B3 S Bi-Turbo
  • 2017– Alpina F32/F33 B4 S Bi-Turbo
  • 2018– Alpina F32/F33 B4 S Bi-Turbo Edition 99


  • 2011–2018 F06/F12/F13 640i
  • 2012–2013 E82/E88 135is
  • 2012–2015 F20/F21 M135i
  • 2012–2015 F01 740i/Li


  • 2013–2016 F22/F23 M235i
  • 2015–2016 F20/F21 M135i LCI


  • 2013–2015 F30 ActiveHybrid 3


  • 2015–2018 F26 X4 M40i — 265 kW (355 bhp)
  • 2016–2018 F87 M2 — 272 kW (365 bhp)

For more information on Tuning your BMW engine please join us in our friendly forum where you can discuss N55 tuning options in more detail with our N55 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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We really like hearing from our readers, and hearing about which upgrades were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our guides and tips are kept up to date.

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