Comprehensive guide to modifying the N63 engine from BMW

Tuners tips on "BMW N63 Tuning"

BMW N63 Tuning Guide

"Modification guide to tuning the N63!"

Our aim here is to outline options for your N63 tuning and point out the greatest modifications. BMW N63 are awesome to work on and with the ultimate parts like remapping, turbo improvements and camshafts you will definitely enhance your driving experience.

Just because particular mods are popular with N63 owners it doesn't mean you should fit it, instead we will concentrate) on the top mods that will give your N63 the best power gain for you money.

Significant gains on the N63 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 push up the power through the rev band, you could drop a little bottom end torque but your higher rpm power will be higher.

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

A Motorsport and race camshaft will just annoy you whilst in heavy traffic.

You should ideally optimize your engines power to your cars usage so for a car used daily stick with a shorter duration N63 camshaft

Each engine responds better to extreme cam durations check your engine on a rolling road.

The engine timing and fuelling also will say much on the bhp gains you'll make.

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

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

Stage 3 mods: Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Engine balancing & blueprinting, Competition cam, Twin charging conversions.Review your options and then buy your modifications and set yourself a power target to avoid disappointment.

ECU mapping helps fully realize the full potential of all the tuning parts you've done to your N63.

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 may depend much on the tuning parts you've carried out and the condition of your engine.

Forcing more air into your N63 is the whole point to any engine tuning job.

Intake take the air during the suck phase from the air filter and allow it to be drawn into the engine and mixed with fuel.

Shape and rate of flow of the Headers can make a substantial effect on to fuel delivery on the N63.

It's not uncommon that intake headers are begging for aftermarket tuning parts, although a few manufacturers provide fairly well optimized intake headers.

Adding a N63 larger valve kit, carrying out port work and head flowing will also increase torque, & importantly will allow you to get a better torque increase on other modifications.

Turbo upgrades

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 a separate 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 N63

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

If an engine has a turbo already fitted modifications are giving better power gains and you'll see that turbo charged engines are built using better components.However you'll find engines have limits

We recommend you find these limitations and upgrade to higher quality crank and pistons to handle the power.

We see many car owners spending a loads of money on turbo upgrades on the N63 only to experience the engine block go up in smoke soon after it's been completed.

Big upgraded turbo chargers commonly suffer no power at low rpm, and smaller turbo chargers spool up more quickly but won't have the peak end engines power gains.

We are pleased that the choice of turbo chargers is always improving and we commonly find variable vane turbo chargers, where the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

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

It is not unusual that there's a restriction in the air flow sensor AFM/MAF on the N63 when loads more air is being fed into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting bhp and torque at a much lower level.Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large bhp and torque gains, although more challenging to setup. We have this article on twincharging if you want to read more.

Fuelling upgrades and mods

Don't overlook the need to boost the fuel system when you are increasing the performance - it makes the car more thirsty. 

Most tuners we speak with say to over specify your flow rate on the injectors.

The rule of thumb is to add 20% capacity when fitting an injector, this allows for injector deterioration and gives a bit of 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..

N63 Exhaust upgrades and mods

You may need to boost your exhaust if the existing exhaust is creating a flow problem.

On most factory exhausts you should find that 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.Please dont run with the widest exhaust you can source you'll slow the exhaust rate - the best exhausts for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

Typically exhaust restrictions can be traced to the catalyst and filters installed, so adding a faster flowing race alternative will help avoid this restriction.

N63 Weak spots, Issues & common problem areas

The N63 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the N63, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your N63 engine please join us in our friendly forum where you can discuss tuning options in more detail with our N63 owners. It would also be worth reading our unbiased 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 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 N63 guides and tips are kept up to date.




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