MENUTuning Feature: Nissan HR12DE Modified
"Comprehensive guide to performance parts and tuning the Nissan HR12DE engine!"
We are frequently getting messages requesting info on the best HR12DE mods that work. So let us look into Nissan HR12DE mods and outline the best upgrades on this great engine and point out some problems along the way.
Our aim here is to review HR12DE tuning and outline the premier modifications. Nissan HR12DE great bases for a tuning project and with the best performance upgrades like remapping, turbo upgrades and camshafts you will greatly improve the drivers enjoyment of your car.
When talking about the top parts for your HR12DE engine, we are going to focus on the ones that give the best power gain for you spend.
Significant power gains can be made on engines, and the HR12DE is no exception, from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.
NB: Fast road camshafts commonly increase the bhp through the rpm band, you could sacrifice a little bottom end torque but your higher rpm power will be higher.
Motorsport camshafts, increase the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.
For a road car one, ideally, need to match your torque band to your cars usage.
I'd be amazed if you find a HR12DE Competition cam is a pleasure to live with when driving around busy urban areas.
Different HR12DE engines respond better to more aggressive cam durations than others.
The map and fuelling also have a large bearing on the power gains you'll hit.
Longer 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.
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Guide to the Best HR12 DE Tuning Mods & Upgrades
- Mods that Remove a Restriction
If the intake or exhaust are restricted in any way this will have an impact on your car's performance, so use an induction kit/filter upgrade and better flowing exhaust whenever your tuning creates a flow restriction.
- Mods that Improve Handling
Braking, Suspension, and general alignment of the suspension components are vital for any tuning project even before you start increasing power.
- Fit Stronger Parts
Tuned cars will show up weaknesses, typically in the turbochargers, clutch, and internal engine components. Whilst most engines can cope with mild tuning mods, TorqueCars recommend that you upgrade the internal components before these weak spots manifest themselves.
- ECU Tunes & Remapping
While some cars can be easily remapped, others may require piggyback ECU's or aftermarket ECU's but this is the most vital step of your tuning project as it fully releases the power from all of your mods and upgrades. Expect 10-20% on NASP engines and 30-40% on turbocharged units.
- More Power Needs More Fuel & Air
Every tuning project will aim to increase the air supply, but fuel supply is just as vital and will need to match the air the engine can utilise. Fuel to Air ratio is vital so upgrade the fuel pump & injectors. Also, you can look to perform head mods (flowing and porting), bigger valves, fast road cams, and forced induction upgrades to improve fuel.
HR12DE Tuning Stages
Stage 1 HR12DE modifications: Fast road camshaft, Sports exhaust manifold, Drilled & smoothed airbox, Remaps/piggy back ECU, Intake headers, Panel air filters.
Stage 2 HR12DE modifications: high flow fuel injectors, Fast road cam, Ported and polished head, induction kit, fuel pump upgrades, Sports catalyst & performance exhaust.
Stage 3 HR12DE modifications: Internal engine upgrades (head flowing porting/bigger valves), Crank and Piston upgrades to alter compression, Twin charging conversions, Competition cam, Adding or Upgrading forced induction (turbo/supercharger), Engine balancing & blueprinting.
A remap helps release the full potential of all the tuning parts you've done to your HR12DE.
It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output may depend much on the tuning parts you've carried out and the condition of your engine.
Forcing fuel and air into the HR12DE engine is the aim to any engine modification job.
The intake plenum flow the air from the intake filter and allow it to be fed into the engine cylinders.
Structure and rate of flow of the Intake can make a big difference to to fuel atomisation on the HR12DE.
On popular production engines plenum chambers are crying out for an upgrade, although some car makers provide reasonably good plenum chambers.
Fitting big valve kits, getting port matching and head flowing will also increase power, this will allow you to get an improved power increase on other parts.
Turbo upgrades for the HR12DE
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 HR12DE
The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.
When your motor is turbo charged parts are more reliable and you'll see that turbocharged engines are made using more solid components.
However most engines have limits
Discover these restrictions and install better quality components to handle the power.
We see many car owners spending a lot of money on turbocharger upgrades on the HR12DE only to watch the HR12DE explode when it's been finished.
Large capacity turbochargers often experience low end lag, and small turbochargers spool up quickly but do not have the top end torque gains.
In the last 10 years the selection of turbos is always increasing and we commonly find variable vane turbos, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.
Twin scroll turbos divert the exhaust flow into 2 channels and direct these at differently designed vanes in the turbo. They also increase the scavenging effect of the engine.
It is common that there is a restriction in the air flow sensor MAF/MAP on the HR12DE when loads more air is being fed into the engine.
Going up you'll find 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 bhp gains, although harder to install. We have this article covering twinchargers if you want to read more.
Uprating HR12DE fuel injectors
When you increase the torque you will need to ramp up to the fuel delivery.
More torque needs more fuel. 
It makes sense to over specify your flow rate on the injectors.
As a rule of thumb add 20% to the flow rate when specifying an injector, helps cope with injector deterioration and provides 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 HR12DE performance exhausts
You may need to uprate your exhaust if the existing exhaust is creating a restriction.
On most factory exhausts you'll see your flow rate is good 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 increase the flow of air through the engine.
But if your exhaust is too big, ie: over 2.5 inches bore, you will lose a lot of your flow rate and end up lacking power and torque.
Typically exhaust restrictions come around the catalysts installed, so adding a better flowing race alternative will help avoid this restriction.
Problems and issues to look out for on the HR12DE
The HR12DE 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 HR12DE, particularly when the engine has been modified and is putting down more power than the manufacturer intended.
For more information on Tuning your HR12DE engine please join us in our friendly forum where you can discuss tuning options in more detail with our HR12DE 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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We really like hearing from our readers, and hearing about which modifications were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our HR12DE guides and tips are kept up to date.
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