MENUTuning Feature: Nissan YD25DDTi Modified
"Comprehensive guide to tuning the Nissan YD25DDTi engine!"
We are frequently getting messages requesting info on the best YD25DDTi power upgrades. So let us look into Nissan YD25DDTi tuning mods and outline the best modifications on this great engine and point out some problems along the way.
The Nissan YD25DDTi really good project engines and with carefully chosen modified modifications like remapping, turbo upgrades and camshafts you will greatly maximise your driving pleasure.
Here we review YD25DDTi tuning and summarise the best upgrades.
When talking about the optimum parts for your YD25DDTi engine, we are going to concentrate on the upgrades that give the best power gain for you spend.
Altering your YD25DDTi camshaft will usually make a dramatic difference to your engines bhp. Choosing a higher performance camshaft profile raises the bhp accordingly
NB: Fast road cams commonly increase the bhp through the rev band, you may lose a little bottom end torque but top end will be higher.
Race cams, increase the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.
On a daily driver one, ideally, must carefully try to optimize your bhp range to your cars usage.
You will never find a YD25DDTi Motorsport cam is a pleasure to live with when in heavy traffic.
Some YD25DDTi engines respond better to extreme cam durations than others.
The ecu map and injectors and fuel pump also have an effect on the torque gains you'll get.
Longer valve durations 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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Guide to the best TD25DDTi tuning mods & Upgrades
- ECU Map Tuning & Remaps
Some cars may require a piggyback ECU's or aftermarket ECU's to change the OEM map, but remapping is the most vital step of your tuning project to fully maximise your mods. Expect 10-20% on NASP engines and 30-40% on turbocharged units.
- Strengthen Your Engine
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.
- Mods that Remove a Restriction
A restricted intake or exhaust will have an impact on your performance, so use a better flowing air filter/induction kit and better flowing exhaust (sports cats where legal are a good option) whenever your tuning creates a flow restriction. Turbo engines also benefit from intercooler upgrades as these resist heat soak for longer periods of time.
- Mods that Improve Fuelling
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, a fuel pump and injector upgrade are usual mods, but also in many cases the fuel regulator will need improvement.
- Mods to Provide better Airflow
Increasing the air supply is just as essential as improving fuelling, we suggest you look at head mods (flowing and porting, 5 angle valve jobs), fit bigger valves, fast road cams and forced induction upgrades (adding a better flowing turbo) to improve air intake.
YD25DDTi Tuning Stages
Stage 1 YD25DDTi modifications: Remaps/piggy back ECU, Intake headers, Sports exhaust manifold, Panel air filters, Fast road camshaft, Drilled & smoothed airbox.
Stage 2 YD25DDTi modifications: induction kit, Sports catalyst & performance exhaust, Fast road cam, high flow fuel injectors, fuel pump upgrades, Ported and polished head.
Stage 3 YD25DDTi modifications: Twin charging conversions, Crank and Piston upgrades to alter compression, Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Adding or Upgrading forced induction (turbo/supercharger), Competition cam.
A remap helps release the full potential of all the parts you've done to your YD25DDTi.
It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but the end result usually rely on the parts you've applied and the condition of your engine.
It is the main goal to any engine modification task to feed fuel and air into your YD25DDTi
Intake flow the air during the suck phase from the air cleaner and allow it to be fed into the engine cylinders with fuel for the squish phase.
Shape and flow rate of the Intake headers can make a big improvement to fuel delivery on the YD25DDTi.
It's not uncommon that intake manifold are crying out for an upgrade, although a few manufacturers provide decently flowing intake manifold.
Big valve conversions on the YD25DDTi, carrying out port work and head flowing will also raise performance, and as an added benefit will give you raising the performance increase on other parts.
Turbo upgrades for the YD25DDTi
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 YD25DDTi
The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes impressive power gains.
If your car has a turbo already fitted tuning parts are giving better power gains and turbo engines are built with harder and stronger components.
There are reliable limits for every engine, with some being extremely strong and some only just able to handle stock power
We recommend you find these limits and fit forged components to handle the power.
There are many mechanics spending a a stack of money on turbo charger upgrades on the YD25DDTi only to suffer the indignity of watching the engine block literally blow up just after it's been enthusiastically driven.
Big turbo chargers commonly experience no power at low rpm, and low capacity turbo chargers spool up really quickly but don't have the peak rpm engines power gains.
We are pleased that the world of turbo chargers is always increasing and we are seeing variable vane turbo chargers, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.
Twin scroll turbo chargers divert the exhaust gases into two channels and direct these at differently profiled vanes in the turbo. They also boost the scavenging effect of the engine.
It is common that there is a limit in the air flow sensor MAP/MAF/AFM on the YD25DDTi when loads more air is being sucked into the engine.
Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited power at a much lower level.
Adding a supercharger or additional turbo will make large bhp and torque gains, although more complex to get working. We have this guide to twinchargers if you want to read more.
Uprating YD25DDTi fuel injectors
You will need to ensure that the engine is not starved of fuel so will need to pay attention to the fuelling when you start exceeding 20% of a bhp and torque increase.
Don't forget to be generous with your injectors flow rate.
As a rule of thumb add another 20% when buying an injector, this takes into account 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.
Best YD25DDTi performance exhausts
You only need to to replace your exhaust if the existing exhaust is creating a restriction in flow.
On most factory exhausts you'll find your 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 generally help improve air flow from the engine but avoid an exhaust that is too large or you may end up reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.
Usual exhaust restrictions come around the catalyst installed, so adding a freer flowing high performance alternative will help avoid this restriction.
Problems and issues to look out for on the YD25DDTi
The YD25DDTi 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 YD25DDTi, particularly when the engine has been modified and is putting down more power than the manufacturer intended.
For more information on Tuning your YD25DDTi engine please join us in our friendly forum where you can discuss tuning options in more detail with our YD25DDTi 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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