Tuning guide "HR12DDT Modifications"

How to modify and upgrade the Nissan HR12DDT

"Comprehensive guide to tuning the Nissan HR12DDT engine!"

TorqueCars are always getting posts asking how to improve the HR12DDT from people wanting to know what are the premier HR12DDT power upgrades. So let us look into Nissan HR12DDT modifications and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Nissan HR12DDT offer good returns when tuned and with carefully chosen tuning upgrades like a remap, turbo improvements and camshafts you will really enhance your driving experience.

Our aim here is to look into HR12DDT tuning and highlight the greatest mods that work.

The ultimate HR12DDT tuning mods on an engine are in our opinion the ones that give the biggest return for your money.

We won't be swayed by popular HR12DDT tuning mods, they need to be cost effective.

Improving air intake on the HR12DDT

You need air matched to fuel for an engine to work. If there is a lack of fuel then it will run lean, if there is insufficient air it runs rich losing power which risks damage to the HR12DDT. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Pulling more air and fuel into the HR12DDT engine is the main goal to any engine performance tuning job.

You'll commonly see there's a limitation in the air flow sensor AFM/MAP on the HR12DDT when considerably 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 sapped power at a much lower level.

The intake plenum transmit the air during the suck phase from the filter and allow it to be fed into the engine and mixed with fuel.

The shape and rate of flow of the Intake can make a substantial difference to to fuel engine efficiency on the HR12DDT.

Most air intake manifolds are in desperate need of an upgrade, although a few manufacturers provide fairly well optimized air intake manifolds.

Larger HR12DDT valves, carrying out HR12DDT port enlargement and head flowing will also increase power, and more importantly will raise potential for a better power increase on other parts.

HR12DDT performance cam tips.

Some HR12DDT engines respond better to extreme camshaft durations check your engine on a rolling road.

The ECU mapping and fuelling also have a large bearing on the bhp gains you'll get.

A longer valve duration 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.

Altering your HR12DDT camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

NB: Fast road camshafts normally boost the torque through the rev band, you may sacrifice a little low down bhp but the top end will be higher.

Motorsport and race camshafts, boost the top end 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 optimize your engines power to your typical driving style.

I'd be gobsmaked if you have ever thought a HR12DDT Competition camshaft is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the HR12DDT

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 HR12DDT parts:

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

Stage 2 HR12DDT parts:

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

Stage 3 HR12DDT parts:

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

A remap will help unlock the full potential of all the tuning parts you've done to your HR12DDT.

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

Turbo modifications on the HR12DDT

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 HR12DDT.

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

If a car has forced induction parts are simpler to install and most turbo charged engines are made with many forged and stronger components.

There are reliable limits for every engine, with some being incredibly solid and some only able to handle stock power

Discover these limits and upgrade to better quality crank and pistons to cope with the power.

We've seen people spending a loads of money on turbo upgrades on the HR12DDT only to suffer the humiliation of seeing the engine block explode soon after it's completed.

Big capacity turbo chargers often suffer no power at low rpm, and small turbo chargers spool up more quickly but won't have the high rpm torque gains.

Thankfully the market of turbo chargers is always evolving and we are seeing variable vane turbo chargers, permitting the vane profile is altered according to speed to lower lag and increase top end performance.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large power gains, although more challenging to install. We have this article covering twinchargers if you want to read more.

Tips about fuel supply on the HR12DDT

When you improve the torque you will need to uprate to the fuel delivery.

More torque needs more fuel. Experienced tuners recommend to over specify your flow rate on the injectors.

The rule of thumb is to add 15% to the flow rate when specifying an injector, this takes into account injector deterioration and gives 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..

Recommended HR12DDT performance exhaust upgrades

We'd only recommend you look to upgrade your exhaust system with an upgraded one is if your exhaust is actually causing a restriction in flow.

On most factory exhausts you should find that the exhaust flow rate is still ok 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.

Please dont run with the widest exhaust you can find you'll slow up the exhaust flow rate - the best 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.

Usual exhaust restrictions can be traced to the filters installed, so adding a freer flowing high 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 HR12DDT

Like most engines an HR12DDT, 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 HR12DDT, failure to do this will exacerbate engine wear, on a tuned HR12DDT 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 HR12DDT why not pop over to the forums at TorqueCars where you can chat about HR12DDT tuning options and read about others projects who may be planning to do similar modifications on their HR12DDT.

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