Everything You Need To Know About "MR18DE Modifications"

How to modify and upgrade the Nissan MR18DE

"Comprehensive guide to tuning the Nissan MR18DE engine!"

Forums like the one at TorqueCars are always getting messages asking about how to improve the MR18DE from people inquiring about getting more power from the MR18DE and wanting to know what are the things tuners recommend when it comes to MR18DE modifications. So let us look into Nissan MR18DE parts and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Nissan MR18DE are popular engines and with the best modified parts like ECU maps, turbo upgrades and camshafts you will certainly maximize your driving pleasure.

Here we provide a guide to MR18DE tuning and summarise the premier modifications.

The optimum MR18DE modifications on an engine are obviously the ones that give the best power gain for your hard earned cash.

We won't be swayed by popular MR18DE modifications, they need to be cost effective.

Improving air intake on the MR18DE

You need air matched to fuel for an engine to work. If there is too little fuel then it will run lean, if there is insufficient air it runs rich sapping power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So the goal to any engine performance tuning job to get fuel and air into your MR18DE but this has a knock on effect with the air flow sensor.

You'll commonly see there's a limitation in the air flow sensor AFM/MAF on the MR18DE when a lot more air is being sucked into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting power at a much lower level.

Engine intake manifolds flow the on the suck phase from the filter and allow it to be drawn into the engine cylinders with fuel for the squish phase.

The size of bore and shape and flow characteristics of the Plenum can make a substantial effect on to fuel engine efficiency on the MR18DE.

We often see intake headers are in dire need of motorsport parts, although some OEM provide fairly well optimized intake headers.

Increasing the MR18DE valve size, getting port matching and head flowing will also raise bhp and torque, & importantly will allow you to get raising the bhp and torque increase on other upgrades.

MR18DE performance cam tips.

Different MR18DE engines respond better to mild cam durations than others.

The ECU mapping and fuel pump and injectors also will make differences on the power gains you'll make.

Extending exhaust or intake 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.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large bhp gains are on offer for cam upgrades.

NB: Fast road cams normally increase the torque across the rpm band, you could drop a little low end torque but your top end will be higher.

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 Motorsport and race camshaft makes it harder when in heavy traffic.

You should ideally match your engines power to your preferences so for a car used daily stick with a fast road MR18DE camshaft

Stage 1, 2 and 3 mods for the MR18DE

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 MR18DE parts:

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

Stage 2 MR18DE parts:

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

Stage 3 MR18DE parts:

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, Twin charging conversions.

Mapping helps to establish the full potential of all the upgrades you've done to your MR18DE.

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 differs on the upgrades you've fitted and the condition of your engine.

Turbo modifications on the MR18DE

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 MR18DE.

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.

When the engine is turbocharged, tuning mods are going to make more power and you will discover turbo engines are made with more solid components.

However engines will have power limits

Research these restrictions and install stronger pistons, crank and engine components to handle the power.

We see many guys spending a lots of money on turbo charger upgrades on the MR18DE only to experience the MR18DE catastrophically fail soon after it's finished.

Large capacity turbo units commonly suffer no power at low rpm, and small turbo units spool up really quickly but do not have the top end bhp gains.

Thanks to new tech the world of turbo units is always developing and we now see variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo units divert the exhaust flow into two channels and flow these at differently designed vanes in the turbo. 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 performance gains, although harder to setup. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the MR18DE

You will need to ensure that the engine is not starved of fuel so need to increase the fuelling when you start going beyond 20% of a torque hike. We would recommend you to be generous with your injectors flow rate.

The accepted safe increase is to add 15% to the flow rate when specifying an injector, helps cope with injector deterioration and allows 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 MR18DE performance exhaust upgrades

You should look to improve your exhaust system with an upgraded one is if the existing exhaust is actually causing a flow problem.

On most factory exhausts you'll find 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.

Note that with the widest exhaust you can get this will slow the exhaust rate - the best exhausts 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.

Typically exhaust restrictions are in the catalysts installed, so adding a freer flowing performance alternative will help avoid this restriction.

Decat pipes (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the MR18DE

Like most engines an MR18DE, 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 MR18DE, failure to do this will exacerbate engine wear, on a tuned MR18DE 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 MR18DE why not pop over to the forums at TorqueCars where you can chat about MR18DE tuning options and read about others projects who may be planning to do similar modifications on their MR18DE.

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