Car tuning tips:QR20DD Modifications"

How to modify and upgrade the Nissan QR20DD

"Comprehensive guide to performance parts and tuning the Nissan QR20DD engine!"

TorqueCars are always seeing threads about how to improve the QR20DD from people inquiring about getting more power from the QR20DD and wanting to know what are the premier QR20DD mods that work. So let us look into Nissan QR20DD mods and outline the best modifications on this great engine and point out some problems along the way.

In this article we consider QR20DD tuning and outline the ultimate modifications. Nissan QR20DD are popular engines and with the right tuning parts like remaps, turbo kits and camshafts you will certainly maximise your driving experience.

When talking about the ultimate parts for your QR20DD engine, we are going to concentrate on the tuning parts that give the best power gain for you money.

Improving air intake on the QR20DD

You need air and fuel for an engine to work. If there is insufficient fuel then it will run lean, if there is not enough air it runs rich sapping 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 Feeding air and fuel into each cylinder is vital to any engine modification job.

You'll commonly see there is a limitation in the air flow sensor AFM/MAP on the QR20DD when a lot 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 bhp at a much lower level.

Engine intake manifolds transmit the on the suck phase from the air filter and allow it to be sucked into the engine and mixed with fuel.

The shape and flow characteristics of the Intake headers can make a substantial difference to to fuel engine efficiency on the QR20DD.

Most intake are ripe for aftermarket tuning parts, although some manufacturers provide decently flowing intake.

Fitting big valve kits, doing some port work and head flowing will also boost bhp and torque, and significantly will permit a greater bhp and torque increase on other parts.

QR20DD performance cam tips.

Different QR20DD engines respond better to less aggressive camshaft durations check your engine on a rolling road.

The engine timing and injectors and fuel pump also will say much 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.

Significant air intake, and exhaust improvements on the QR20DD can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

NB: Fast road camshafts commonly raise the bhp and torque throughout the rpm band, you could drop a little bottom end power but your high end rpm power will improve.

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

In a typical daily driver you must carefully try to match your torque band to your preferences.

I'd be gobsmaked if you find a QR20DD Competition cam is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the QR20DD

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 QR20DD parts:

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

Stage 2 QR20DD parts:

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

Stage 3 QR20DD parts:

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

ECU mapping helps release the full potential of all the parts you've done to your QR20DD.

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 often rely on the parts you've done and the condition of your engine.

Turbo modifications on the QR20DD

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 QR20DD.

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

When an engine has forced induction upgrades are giving better power gains and we find turbo engines use harder and stronger components.

However every engines will need better parts at higher power limits

We recommend you find these limits and fit higher quality components to cope with the power.

We see many people spending a lots of money on turbo charger upgrades on the QR20DD only to suffer the indignity of watching the car explode on it's first outing after it's first rolling road session.

Big upgraded turbo chargers will usually experience low end lag, and smaller turbo chargers spool up really quickly but don't have the top end power band gains.

In recent times the world of turbo units is always moving on and we are seeing variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end power.

Twin scroll turbo units divert the exhaust gases into a couple of channels and push these at differently profiled vanes in the turbo. They also help 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 setup. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the QR20DD

Don't overlook the need to raise the fuelling when you are increasing the power - it makes the car more thirsty. At this point we flag up the need to over specify your flow rate on the injectors.

The rule of thumb is to add 20% when fitting an injector, this allows for injector deterioration and gives 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 QR20DD performance exhaust upgrades

Only look to uprate your exhaust system with an upgraded one is if your current exhaust is actually creating a restriction.

On most factory exhausts you'll find the exhaust 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 usually air flow from the engine but avoid an exhaust that is too wide or you may end up will reduce the flow rate. Stick to one and a half to two and half inches as a rule of thumb.

Typically exhaust restrictions can be located the catalyst and filters installed, so adding a higher flowing performance alternative will help avoid this restriction.

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

Faults issues and things to look out for on the QR20DD

Like most engines an QR20DD, 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 QR20DD, failure to do this will exacerbate engine wear, on a tuned QR20DD 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 QR20DD why not pop over to the forums at TorqueCars where you can chat about QR20DD tuning options and read about others projects who may be planning to do similar modifications on their QR20DD.

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This entry was posted under Makes and Models. Tags: engine, nissan
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