Comprehensive guide to performance parts and tuning the N52 engine from BMW

Modifying and improving: "Tuning the BMW N52"

Tuning the BMW N52 Guide

"Comprehensive guide to tuning the BMW N52 engine!"

The BMW N52 great bases for a tuning project and with a few sensible modified tuning mods like ECU maps, turbo improvements and camshafts you will definitely improve your driving fun.

Here we review and look at N52 tuning and highlight the premier modifications.

When talking about the greatest parts for your N52 engine, we are going to focus on the modifications that give the best power gain for you money.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large torque gains are on offer for cam upgrades.

NB: Fast road camshafts tend to bump the bhp over the rev range, you could sacrifice a little low down bhp but the higher rpm power will be lifted.

Race camshafts, bump the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Competition camshaft won't do well if driving in heavy traffic.

You should ideally match your power band to your cars usage so for a typical daily driver stick with a shorter duration N52 camshaft

Different N52 engines respond better to more or less aggressive cam durations so view each engine as unique.

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

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.

Our top 7 top upgrades for your motor, and we will break these into stages and discuss them in detail for you.

  1. Map Tunes - remapping, via either OBD port, or piggyback ECU's and aftermarket ECU's can all make decent gains
  2. Fuelling Pump Injectors - You'll need to match the greater air flow with more fuel to unlock the power
  3. Turbo upgrades - Improving the intake charge with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex especially where conversions are required).
  4. Suspension Upgrades - always improve your cars handling, tuning is not just about engine mods
  5. Brake Upgrades - Even before adding power improve your cars brakes to effectively stop the car
  6. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  7. Exhaust - as with intakes it helps to remove a restriction in the exhaust, cats are the usual bottleneck

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

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

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

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

ECU mapping helps release the full potential of all the tuning parts you've done to your N52.

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 your mileage usually vary depending on the tuning parts you've applied and the condition of your engine.

It is the aim to any engine upgrade project to push air and fuel into your N52

Headers take the air from the air filter and allow it to be drawn into the engine cylinders.

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

The size of bore and shape and flow characteristics of the Air Intake manifolds can make a large improvement to fuel delivery on the N52.

Most plenum chambers are ripe for a performance upgrade, although a few OEM provide fairly well optimized plenum chambers.

Increasing the N52 valve size, getting port matching and head flowing will also improve bhp, and importantly will permit raising the bhp increase on other mods.

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 N52

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 is fitted with a turbocharger modifications are more reliable and you will discover turbocharged engines are made using more solid components.There are common areas of failure for every engine, with some being extremely strong and some only just able to handle stock power

Research these restrictions and fit more solid crank and pistons to survive the power.

We see many guys spending a loads on turbocharger upgrades on the N52 only to have the engine throw a rod soon after it's completed.

Larger capacity turbochargers commonly experience low end lag, and low capacity turbochargers spool up quickly but do not have the peak rpm bhp gains.

Thanks to new tech the range of turbo chargers is always improving and we now see variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

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

You'll commonly see there is a limit in the air flow sensor (AFM/MAF/MAP) on the N52 when a lot more air is being fed into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped 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 gains, although harder to setup. We have this feature on twinchargers if you want to read more.

Fuelling upgrades and mods

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

It is important to be generous with your injector capacity.

As a rule of thumb add another 20% when specifying an injector, this takes into account injector deterioration and allows you some spare capacity should the engine need 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..

Exhaust upgrades and mods

Only look to increase your exhaust if the current exhaust is actually causing a restriction in flow.

On most factory exhausts you should find that the flow rate is ok 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 can usually air flow from the engine but avoid an exhaust that is too large or you could will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Usual exhaust restrictions come around the emissions filters installed, so adding a freer flowing high performance alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the N52

The N52 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the N52, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your N52 engine please join us in our friendly forum where you can discuss tuning options in more detail with our N52 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 N52 guides and tips are kept up to date.

Additional references

Tuning the BMW N52 and best N52 performance parts.

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