MENUNissan QR25DD Tuning
"All you need to know about tuning the Nissan QR25DD engine!"
The Nissan QR25DD are fantastic to work on and with the ultimate tuning modifications like remaps, turbo improvements and camshafts you will positively increase your driving opportunities.
TorqueCars will consider QR25DD tuning and provide tips on the best upgrades.
History, Power & Specs of the QR25DD Engine
- QR25DD 168 hp at 5600 rpm 181 lbft at 4000 rpm
Tuning the Nissan QR25DD and best QR25DD performance parts.
Best QR25DD mods
Just because particular upgrades are are common on QR25DD it doesn't mean it is good, instead we'll focus on the best upgrades that will give your QR25DD the best power gain for you spend.
Significant gains on the QR25DD can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.
Fast road cams tend to bump the bhp over the rev range, you may lose a little low down bhp but your top end will be higher.
Race cams, bump the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.
QR25 cam specs
- Stock: 244 intake 232 exhaust
- Typical stage 1 cams: 262-264 intake 242-256 exhaust
- Race cams: 264-272 intake 257-264 exhaust
In a typical daily driver you need to match your bhp range to your usage of the car.
You'll never think that a QR25DD Motorsport camshaft is a pleasure to live with when driving around busy urban areas. This is because a competition cam causes a very lumpy idle, and makes the car more prone to stall or jerk along in stop start traffic, sadly though many ignore this and end up ruining a perfectly good car and having to revert back to a fast road, or OEM cam profile.
Some QR25DD engines respond better to more aggressive cam durations check your engine on a rolling road.
The ECU mapping and fuelling also have an effect on the torque gains you'll make.
A longer valve duration can alter the torque 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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Best Engine Mods for your car
- Engine Tunes - engine tuning/remapping provides the most advantage in terms of cost savings, aftermarket ECUs, and piggyback ECUs are all alternatives.
- Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
- Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
- Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
- Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.
- 58 PSI 340cc/min 200hp
- 58 PSI 511cc/min 300hp
- 58 PSI 285cc/min 200hp
- 58 PSI 426cc/min 300hp
- 58 PSI 312cc/min 200hp
- 58 PSI 468cc/min 300hp
Typical stage 1 mods often include:
Panel air filters, Sports exhaust header/manifold, Fast road camshaft, Intake manifolds, Remaps/piggy back ECU, drilled & smoothed airbox.
Typical stage 2 mods often include:
high flow fuel injectors, Sports catalyst & performance exhaust, fuel pump upgrades, induction kit, Fast road cam, Ported and polished head.
Typical stage 3 mods often include:
Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Internal engine upgrades (head flowing porting/bigger valves), Twin charging conversions, Competition cam, Engine balancing & blueprinting.
ECU flashing allows a tuner to establish the full potential of all the parts you've done to your QR25DD.
(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)
It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but the outcome usually depend much on the parts you've carried out and the condition of your engine.
It is the main goal to any engine modification project to feed air into the QR25DD engine
Intake manifolds carry the air during the suck phase from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.
Structure and flow characteristics of the Plenum can make a large change to fuel mixing and power on the QR25DD.
On popular production engines intake manifolds are ripe for aftermarket parts, although a few car makers provide reasonably good intake manifolds.
Adding a QR25DD larger valve kit, getting port matching and head flowing will also raise performance, and more importantly will afford you increasing the performance increase on other mods.
QR25DD Turbo upgrades
NA (naturally aspirated) 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 QR25DD
The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes major power gains.
When the engine is fitted with a turbo upgrades are going to make more power and we find turbocharged engines are made using better components.
There are practical limits for every engine, with some being incredibly solid and some only able to handle stock powerSee where you'll find these limits and install better pistons and crank to cope with the power.
We've seen tuners spending a lot of money on turbo charger upgrades on the QR25DD only to suffer the humiliation of seeing the engine block catastrophically fail just after it's been enthusiastically driven.
Large turbos often suffer low end lag, and low capacity turbos spool up much more quickly but don't have the peak end power band gains.
In recent times the range of turbochargers is always increasing and we are seeing variable vane turbochargers, permitting the vane angle is altered according to speed to lower lag and increase top end torque.
Twin scroll turbochargers divert the exhaust gases into a couple of channels and direct these at differently designed vanes in the turbo. They also increase the scavenging effect of the engine.
It is not unusual that there is a limitation in the air flow sensor MAP/MAF/AFM on the QR25DD when considerably more air is being sucked into the engine.
You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp at a much lower level.
Adding a supercharger or additional turbo will make large bhp gains, although more difficult to setup. We have this guide to twinchargers if you want to read more.
Fuelling
Don't forget to look at the fuel system when you are increasing the torque - it makes the car more thirsty. 
We would recommend you to over specify your injector capacity.
As a rule of thumb add 20% capacity when specifying an injector, this allows for injector deterioration and gives some spare capacity should the engine need 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.
All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.
4 Cylinder turbocharged engines
4 Cylinder NA (naturally aspirated) engines
4 Cylinder supercharged engines
QR25DD Performance Exhausts
You may need to uprate your exhaust if the existing exhaust is creating a restriction.
On most factory exhausts you'll find your flow rate is fine 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 largest exhaust you can get you'll 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.
Typically exhaust restrictions can be traced to the catalyst installed, so adding a higher flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.
Weak spots, Issues & problem areas on the QR25DD
The QR25DD engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oil to ensure longevity. Few problems should happen as long as they are regularly serviced and maintained.
Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.
Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.
Regular oil changes are vital on the QR25DD, especially when tuned and will help extend the life and reliability of the engine.
If you would like to know more, or just get some friendly advice on Tuning your QR25DD engine please join us in our car forums where you can discuss QR25DD tuning options in more detail with our QR25DD owners. It would also be worth reading our unbiased Nissan tuning articles to get insights into each modification and how effective they will be for your car.
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