MENUGuide to tuning the N54 engine from BMW
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 N54B30
A turbocharged straight 6 which was in production between 2006 to 2016.
One of BMW's first forays into a mainstream turbo application, it shared much design wise with the N53.
Using two small turbos the engine doesn't feel like a turbocharged engine, but gives the impression of a very large capacity high torque engine.
Using direct injection BMW were able to keep a relatively high compression ratio and avoid the issue of detonation.
The Alpina tuned version gives inspiration to those looking to tweak this great little engine.
- 2006–2010 E90/E91/E92/E93 335i
- 2007–2010 E60/E61 535i
- 2007–2010 E82/E88 135i
- 2008–2010 E71 X6 xDrive35i
- 2009–2016 E89 Z4 sDrive35i
- 2008–2012 F01 740i
- 2011–2013 E92/E93 335is
- 2011 E82 1 Series M Coupe
- 2011–2016 E89 Z4 sDrive35is
- 2007–2010 Alpina B3
- 2012–2013 Alpina B3 GT3
Power output ranged between 302bhp and 402bhp on the top Alpina version.
What are the most effective N54 mods
The greatest 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 tuning parts, they need to be cost effective.
A remap on the N54 engine will give you around 100bhp more which has to rate as one of the best and most cost effective upgrades, second only to turbo upgrades.
Significant gains can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.
Fast road cams tend to increase the power throughout the rpm range, you could drop a little bottom end torque but the top end will be lifted.
Competition cams, increase the top end 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 match your power band to your driving style. We rarely find a Competition cam is a pleasure to live with when driving in heavy traffic.
Different engines respond better to more or less aggressive cam durations check your engine on a rolling road.
The engine timing and fuelling also have an effect on the power gains you'll get.
Altering valve durations can alter the power 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.
Getting air into the N54 engine is vital to any tuning project. If you have done other mods you could be losing around 20hp if the intake is not upgraded.
Headers take the air from the filter and allow it to be drawn into the engine.
Shape and flow rate of the headers can make a large difference to fuel atomization and engine efficiency.
Most intake headers are crying out for an upgrade, although some makers provide reasonably well designed headers.
Increasing the N54 valve size, doing some port matching and head flowing will also improve power, and more importantly will allow you to get a better power increase on other mods.
N54 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.
Going for a big single turbo will help you reach the top end power figures, but you will lose some of that lovely low end instant boost that the N54 is famed for.
We would prefer to mount twin hybrid or upgrade to twinscroll turbos for ease, cost and overall drivability in everyday conditions.
Adding a front mounted intercooler will allow you to enjoy your cars power for longer, as the OEM intercoolers start to suffer from heat soak and become less effective as they warm up.
When an engine has a turbo already fitted upgrades are relatively easy and most turbo engines already contain stronger components. The Alpina version is a case in point, where revised turbos and mapping significantly increased the power output.
It is important to find these limits and install stronger pistons, crank and engine components to cope with the power. We've seen people spending a lot of money on turbo upgrades on the $e only to watch the whole thing literally blow up just after it's been completed.
Large turbos tend to suffer from low end lag, and smaller turbos spool up really quickly but do not have the top end power gains.
Thankfully the world of turbos is always moving on and we are seeing variable vane turbos, where the vane profile is altered according to speed to lower lag and increase top end power.
Twin scroll turbos divert the exhaust into 2 channels and direct these at differently profiled vanes in the turbo. They also improve the scavenging effect of the engine.
It is common for there to be a restriction in the air flow sensor (AFM/MAF/MAP) on the N54 when a lot more air is being pulled into the engine. We see 4 bar air sensors coping with quite large power gains, wheras the OEM air sensor was restricting power at a much lower level.
Adding a supercharger or additional turbo will make large power gains, although more complex to setup. We have a twincharger guide if you want to read more.
Fuelling
Fuel injectors and fuel pump will usually need to be upgraded when you start going beyond 20% of a power increase.
It is important to over specify your injector capacity. Most tuners will take the fuel need and add another 20% when fitting an injector, this allows for injector deterioration and gives a little spare capacity should the engine need more fuel.
N54 Exhaust
You only need to upgrade your exhaust if your current exhaust is creating a restriction. Most OEM exhausts flow 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.
The downpipe seems to be where most N54 owners make power, with a typical power loss before the upgrade of around 50bhp on a standard remap.
Typically exhaust restrictions come around the catalyst and filters installed, so adding a higher flowing sports alternative will help avoid this restriction.
Weakspots and problem areas on the N54
The N54 engines are generally reliable and solid as long as they are regularly serviced and maintained.
Regular oil changes are vital on the N54, especially when tuned and will help extend the life and reliability of the engine.
High Pressure Fuel Pump failures let to a recall in the USA. The issue caused the engine to stop working and cut out.
Keep an eye on the inlet charge pipe, especially when running more power as the OEM plastic ones can split causing leaks. I heard of one friend who was amazed when his split charge pipe was replaced, it totally transformed the car, which he never noticed had a problem!
Wastegates can prematurely wear causing a rattling noise.
For more information on Tuning your BMWengine please join us in our friendly forum where you can discuss N54 tuning options in more detail with our N54 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 mods 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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