Modding uprating the BMW N55B30 engine!

The Lowdown on "N55B30 Modifications"

How to modify and upgrade the BMW N55B30

"Comprehensive guide to tuning the BMW N55B30 engine!"

Sites like TorqueCars are always seeing threads requesting info on how to improve the N55B30 from people wanting to know what are the greatest N55B30 modifications. So let us look into BMW N55B30 parts and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

The BMW N55B30 provide a fun base for your project and with the ultimate tuning enhancements like a remap, turbo kits and camshafts you will really increase your driving enjoyment.

Here we examine the options for your N55B30 tuning and show the greatest mods that work.

The top N55B30 mods on an engine are in our opinion the ones that give the biggest return for your money.

We won't be swayed by popular N55B30 mods, they need to be cost effective.

N55B30 induction kits

Improving air intake on the N55B30

You need air and fuel for an engine to work. If there is too little fuel then it will run lean, if there is a lack of air it runs rich losing power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pushing air into each cylinder is vital to any engine modification job.

It is not unusual that there's a restriction in the air flow sensor MAF/MAP on the N55B30 when considerably 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 limited torque at a much lower level.

Air Intake manifolds carry the air from the intake filter and allow it to be drawn into the engine cylinders.

The shape and flow characteristics of the Intake headers can make a large improvement to fuel atomisation on the N55B30.

I usually find intake manifold are in desperate need of aftermarket parts, although some car makers provide well optimised intake manifold.

Fitting big valve kits, getting port matching and head flowing will also increase torque, and significantly will permit raising the torque increase on other modifications.

N55B30 performance cam tips.

Some N55B30 engines respond better to more aggressive camshaft durations check your engine on a rolling road.

The map and fuel pump and injectors also will say much on the power gains you'll achieve.

A longer valve duration 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.

Altering your N55B30 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

NB: Fast road cams normally boost the bhp and torque through the rpm band, you could sacrifice a little low end torque but the top end will be higher.

Race cams, boost 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 you should ideally to optimize your bhp range to your typical driving style.

I'd be shocked if you find a N55B30 Motorsport and race camshaft is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the N55B30

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 N55B30 parts:

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

Stage 2 N55B30 parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 3 N55B30 parts:

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

Carefully think through your options and then acquire your modifications and set yourself a power target to avoid expensive mistakes.

A remap helps release the full potential of all the tuning mods you've done to your N55B30.

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved usually vary depending on the tuning mods you've carried out and the condition of your engine.

Turbo modifications on the N55B30

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the 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 superb power gains.

When your motor has a turbo already fitted modifications are going to make more power and turbo charged engines already contain strengthened components.

There are tuning limits for every engine, with some being incredibly solid and some only just able to handle stock power

Discover these limitations and fit forged components to survive the power.

We've seen people spending a a stack of money on turbo upgrades on the N55B30 only to suffer the humiliation of seeing the N55B30 go up in smoke soon after it's used on the roads.

Large turbochargers will usually suffer low end lag, and little turbochargers spool up really quickly but won't have the high rpm torque gains.

Over the last 20 years the world of turbochargers is always improving and we commonly find variable vane turbochargers, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large performance gains, although more challenging to setup. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the N55B30

Don't forget to pay attention to the fuel system when you are increasing the performance - it makes the car more thirsty. Experienced mechanics will tell you to over specify your flow rate on the injectors.

The accepted safe increase is to add another 15% when fitting an injector, this accounts for injector deterioration and affords you some spare capacity should the engine require more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended N55B30 performance exhaust upgrades

You may need to upgrade your exhaust system with an upgraded one is if your exhaust is actually creating a flow problem.

On most factory exhausts you'll find the flow rate is good even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

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

But if your exhaust is too large, ie: over two and a half inches diameter, you will lose much of the flow rate and end up losing power and torque.

Usual exhaust restrictions can be traced to the catalysts installed, so adding a faster flowing sports alternative will help avoid this restriction.

Decatting (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the N55B30

Like most engines an N55B30, should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the N55B30, failure to do this will exacerbate engine wear, on a tuned N55B30 this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your N55B30 why not pop over to the forums at TorqueCars where you can chat about N55B30 tuning options and read about others projects who may be planning to do similar modifications on their N55B30.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We want to know your experiences with tuning parts on your N55B30, it helps us improve our tips and keeps us current so please use the comments box to drop a tip.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Check out TorqueCars new YouTube channel, and see their awesome new content...


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article