Modding uprating the BMW N45B16 engine!

Modifying and improving: "N45B16 Modifications"

N45B16 Modifications Guide

How to modify and upgrade the BMW N45B16

"Comprehensive guide to tuning the BMW N45B16 engine!"

Popular tuning sites like TorqueCars are regularly getting emails about how to improve the N45B16 from people wanting to know what are the things tuners are recommending when it comes to N45B16 upgrades. So let us look into BMW N45B16 modifications and outline the best modifications on this great engine and point out some frequent tuning mistakes along the way.

In this article we look at N45B16 tuning and show the best mods that work. BMW N45B16 are awesome to work on and with the right mods like ECU maps, turbo improvements and camshafts you will enhance your driving pleasure.

The optimum N45B16 upgrades on an engine are as we have found the ones that give the best gains for your money.

We won't be swayed by popular N45B16 upgrades, they need to be cost effective.

N45B16 induction kits

Improving air intake on the N45B16

You need air and fuel for an engine to work. If there is not enough fuel then it will run lean, if there is not enough air it runs rich resulting in lost power which risks damage to the N45B16. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Forcing air into your N45B16 is the whole point to any performance tuning project.

It is not unusual that there's a limitation in the air flow sensor MAF/MAP on the N45B16 when considerably more air is being pulled into the engine.

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

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.

Structure and rate of flow of the air Intake manifold can make a large change to fuel atomisation and engine efficiency on the N45B16.

We often see air intake manifolds are in desperate need of aftermarket tuning parts, although a few car makers provide reasonably good air intake manifolds.

Larger N45B16 valves, carrying out port work and head flowing will also boost bhp and torque, and importantly will allow you to get a better bhp and torque increase on other mods.

N45B16 performance cam tips.

Each engine responds better to less aggressive camshaft durations so view each engine as unique.

The engine timing and fuelling also have a large bearing on the power gains you'll make.

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.

Significant air intake, and exhaust improvements on the N45B16 can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams normally raise the power throughout the rev band, you may lose a little low down power but higher rpm power will be lifted.

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

On a typical daily driver you need to optimize your bhp range to your cars usage.

You will never have ever thought a N45B16 Competition cam is a pleasure to live with when driving around busy urban areas.

Stage 1, 2 and 3 mods for the N45B16

Stage 1 N45B16 parts:

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

Stage 2 N45B16 parts:

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

Stage 3 N45B16 parts:

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

Plan your options and then acquire your parts and set yourself a power target to avoid costly mistakes.

Remapping helps release the full potential of all the tuning parts you've done to your N45B16.

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

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 the end result often vary depending on the tuning parts you've applied and the condition of your engine.

Turbo modifications on the N45B16

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 N45B16.

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 the engine has forced induction parts are more reliable and turbocharged engines use uprated components.

However you will find an engines will have power limits

Research these limitations and install better pistons and crank to utilize the power.

There are many tuners spending a fortune on turbocharger upgrades on the N45B16 only to suffer the humiliation of seeing the car throw a rod on it's first outing after it's been completed.

Bigger capacity turbo units commonly suffer no power at low rpm, and small turbo units spool up much more quickly but don't have the peak rpm power band gains.

In the last 10 years the range of turbo chargers is always developing and we now see variable vane turbo chargers, allowing the vane profile is altered according to speed to lower lag and increase top end power.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and direct these at differently designed vanes in the turbocharger. They also boost the scavenging effect of the engine.

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large torque gains, although more complex to install. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the N45B16

You will need to ensure that the engine is not starved of fuel so will need to pay attention to the fuelling when you start extending past 20% of a power hike. Most tuners we speak with say to be generous with your injectors flow rate.

The rule of thumb is to add 15% to the flow rate when fitting an injector, helps cope with injector deterioration and allows 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 N45B16 performance exhaust upgrades

The only time you should look to improve your exhaust system with an upgraded one is if your exhaust is actually creating a restriction.

On most factory exhausts you should find that your flow rate is ok 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 usually air flow through the engine but do not go too large or you could will reduce the flow rate. Stick to one and a half to two and half inches for best results.

The usual suspects causing problems in your exhaust flow rate can be traced to the catalyst installed, so adding a better flowing high performance 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 N45B16

Like most engines an N45B16, 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 N45B16, failure to do this will exacerbate engine wear, on a tuned N45B16 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 N45B16 why not pop over to the forums at TorqueCars where you can chat about N45B16 tuning options and read about others projects who may be planning to do similar modifications on their N45B16.

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