Tuning Feature: Nissan HR12DDR Modified

"Comprehensive guide to performance parts and tuning the Nissan HR12DDR engine!"

We are always seeing threads requesting information on the things we recommend when it comes to HR12DDR power upgrades. So let us look into Nissan HR12DDR parts and outline the best upgrades on this great engine and point out some common pitfalls along the way.

Here we provide a guide to HR12DDR tuning and report on the best modifications for your car. Nissan HR12DDR make awesome project engines and with a few sensible performance tuning mods like ECU maps, turbo upgrades and camshafts you will substantially improve the drivers pleasure of your car.

Just because particular upgrades are are common on HR12DDR it doesn't mean its worth having, instead we will concentrate on the best upgrades to provide your HR12DDR with the biggest power gain return for your cash.

Significant power increases can be made on engines, and the HR12DDR is no exception, from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

NB: Fast road cams usually increase the torque across the rev range, you may lose a little low end power but your top end will improve.

Competition cams, increase the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

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

You should ideally optimize your power band to your typical driving style so for a typical daily driver stick with a mild fast road HR12DDR camshaft

Each engine responds better to more aggressive cam durations so set your engine up on a rolling road.

The engine timing and fuelling also have an effect 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.

HR12DDR Tuning Stages

Stage 1 HR12DDR modifications: Drilled & smoothed airbox, Intake headers, Sports exhaust manifold, Fast road camshaft, Remaps/piggy back ECU, Panel air filters.

Stage 2 HR12DDR modifications: high flow fuel injectors, induction kit, Fast road cam, Ported and polished head, fuel pump upgrades, Sports catalyst & performance exhaust.

Stage 3 HR12DDR modifications: Competition cam, Twin charging conversions, Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting.

ECU flashing helps fully realize the full potential of all the mods you've done to your HR12DDR.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the outcome may vary depending on the mods you've carried out and the condition of your engine.

Forcing fuel and air into the HR12DDR engine is the whole point to any engine tuning job.

Intake headers carry the air from the air cleaner and allow it to be sucked into the engine cylinders.

The shape and rate of flow of the Plenum can make a large difference to to fuel mixing and power on the HR12DDR.

Many mass produced engine intake manifold are improved through aftermarket parts, although some manufacturers provide well optimised intake manifold.

Larger HR12DDR valves, doing some 3 or 5 angle valve jobs and porting and head flowing will also lift bhp and torque, and as an added benefit will make space for a greater bhp and torque increase on other mods.

Turbo upgrades for the HR12DDR

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 HR12DDR

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.

When a car is fitted with a turbocharger parts are relatively easy and most turbocharged engines are built using uprated components.

However you'll find engines will have power limits

See where you'll find these restrictions and upgrade to more solid crank and pistons to survive the power.

We've seen people spending a lot of money on turbo upgrades on the HR12DDR only to suffer the indignity of watching the engine block throw a rod on it's first outing after it's been enthusiastically driven.

Bigger capacity turbochargers will usually experience a bottom end lag, and low capacity turbochargers spool up quickly but won't have the high rpm engines power gains.

We are pleased that the selection of turbos is always developing and we are seeing variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust gases into a couple of channels and direct these at differently profiled vanes in the turbo. They also increase the scavenging effect of the engine.

It is not unusual that there's a restriction in the air flow sensor AFM/MAP on the HR12DDR when loads more air is being pulled into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited performance at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although harder to setup. We have this feature on twinchargers if you want to read more.

Uprating HR12DDR fuel injectors

When you increase the bhp and torque you will need to pay attention to to the fuel system.

More bhp and torque needs more fuel. Don't forget to over specify your flow rate on the injectors.

The accepted safe increase is to add 20% to the flow rate when buying an injector, which takes into account injector deterioration and allows you 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 HR12DDR performance exhausts

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

On most factory exhausts you should find that the exhaust 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.

Don't go with the biggest exhaust you can get this will slow up the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Usual exhaust restrictions are traced to the emissions filters installed, so adding a better flowing performance alternative will help avoid this restriction.

Problems and issues to look out for on the HR12DDR

The HR12DDR 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 HR12DDR, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your HR12DDR engine please join us in our friendly forum where you can discuss tuning options in more detail with our HR12DDR 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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