Tuning Feature: Nissan QR20DD Modified

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

We often are getting emails asking how to improve the QR20DD from people wanting to know what are the optimum QR20DD upgrades. So let us look into Nissan QR20DD mods and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

The Nissan QR20DD are popular engines and with the right performance upgrades like remaps, turbo kits and camshafts you will noticeably improve your driving fun.

Let us review QR20DD tuning and summarise the best mods that work.

Just because particular parts are are common on QR20DD it doesn't mean its worth having, we shall focus on the best parts to provide your QR20DD with 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 power band gains are on offer for cam upgrades.

NB: Fast road cams normally bump the power over the rpm range, you may sacrifice a little bottom end bhp but your high end rpm power will be better.

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

A Motorsport camshaft won't do well if on the daily commute.

You should ideally match your power band to your usage of the car so for a car used daily stick with a fast road QR20DD camshaft

Some QR20DD engines respond better to extreme cam durations so view each engine as unique.

The map and fuel pump and injectors also will make differences on the bhp gains you'll achieve.

Extending exhaust or intake 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.

QR20DD Tuning Stages

Stage 1 QR20DD modifications: Drilled & smoothed airbox, Remaps/piggy back ECU, Fast road camshaft, Intake headers, Sports exhaust manifold, Panel air filters.

Stage 2 QR20DD modifications: fuel pump upgrades, induction kit, Fast road cam, Ported and polished head, Sports catalyst & performance exhaust, high flow fuel injectors.

Stage 3 QR20DD modifications: Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Twin charging conversions, Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Competition cam.

Mapping helps release the full potential of all the upgrades you've done to your QR20DD.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved will rely on the upgrades you've applied and the condition of your engine.

It is the whole point to any engine tuning project to push fuel and air into each cylinder

Air Intake manifolds carry the air during the suck phase from the intake filter and allow it to be pulled into the engine cylinders.

The shape and flow characteristics of the Plenum can make a substantial improvement to fuel mixing and power on the QR20DD.

It's not uncommon that intake manifold are begging for aftermarket parts, although some car makers provide reasonably good intake manifold.

Fitting big valve kits, carrying out 3 or 5 angle valve jobs and porting and head flowing will also raise bhp, and importantly will allow you to get raising the bhp increase on other modifications.

Turbo upgrades for the QR20DD

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your 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 superb power gains.

If the engine has forced induction tuning mods are going to make more power and most turbo engines will have better components.

There are practical limits for every engine, with some being extremely strong and some only able to handle stock power

We recommend you find these restrictions and fit more solid crank and pistons to survive the power.

It's not unheard of people spending a lots of money on turbocharger upgrades on the QR20DD only to see the whole thing catastrophically fail when it's used in anger.

Larger upgraded turbochargers tend to suffer a bottom end lag, and smaller turbochargers spool up much more quickly but won't have the high rpm power band gains.

Thanks to new tech the market of turbo chargers is always developing and we commonly find variable vane turbo chargers, allowing the vane angle is altered according to speed to lower lag and increase top end power.

Twin scroll turbo chargers divert the exhaust flow into two channels and feed these at differently designed vanes in the turbocharger. They also boost the scavenging effect of the engine.

You'll commonly see there is a limit in the air flow sensor AFM/MAF on the QR20DD when considerably more air is being sucked into the engine.

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

Adding a supercharger or additional turbo will make large torque gains, although more challenging to get working. We have this in depth look at twinchargers if you want to read more.

Uprating QR20DD fuel injectors

When you boost the bhp you will need to ramp up to the fuel system.

More bhp needs more fuel. Don't forget to be generous with your injector capacity.

As a rule of thumb add 20% to the flow rate when fitting an injector, this allows for injector deterioration and allows some spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Best QR20DD performance exhausts

You only need to to replace your exhaust if your exhaust is actually causing a restriction in flow.

On most factory exhausts you'll find the flow rate is still 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 help balance the flow of air through the engine.

But if your exhaust is too big, ie: over 2.5 inches bore, you will lose much of your flow rate and end up sapping power and torque.

Usual exhaust restrictions can be located in the catalyst and filters installed, so adding a freer flowing race alternative will help avoid this restriction.

Problems and issues to look out for on the QR20DD

The QR20DD engines, if regularly serviced and maintained, are generally very reliable and have few issues. {But if neglected they can cost a small fortune|When neglected they get very expensive to run|They can however be quite expensive if neglected| }

Regular oil changes are vital on the QR20DD, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your QR20DD engine please join us in our friendly forum where you can discuss tuning options in more detail with our QR20DD owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Nissan. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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