Modding upgrading and tuning the Nissan MR18DE engine!

Modifying and improving: "MR18DE Modifications"

MR18DE Modifications Guide

How to modify and upgrade the Nissan MR18DE

"Comprehensive guide to tuning the Nissan MR18DE engine!"

Our friends at TorqueCars are regularly getting emails asking how to improve the MR18DE from people inquiring about getting more power from the MR18DE and wanting to know what are the premier MR18DE modifications. So let us look into Nissan MR18DE upgrades and outline the best modifications on this great engine and point out some common pitfalls along the way.

Therefore we provide a guide to MR18DE tuning and provide tips on the premier mods that work. Nissan MR18DE are good project engines and with a few sensible motorsport upgrades like a remap, turbo kits and camshafts you will improve your driving enjoyment.

Just because particular tuning mods are are common on MR18DE it doesn't mean you should fit it, instead we'll focus on the ultimate tuning mods that will give your MR18DE the biggest power gain return for your cash.

Without us subscribing to the common myth of 'if it's shiny and makes more noise it must be good' you seem to get in many tuning magazines and on car forums'.

MR18DE induction kits

Improving air intake on the MR18DE

You need fuel and air for an engine to work. If there is not enough fuel then it will run lean, if there is little flow of air it runs rich resulting in lost 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 fundamental goal to any engine modification task to get air and fuel into each cylinder but this has a knock on effect with the air flow sensor.

It is common that there is a limit in the air flow sensor AFM/MAP on the MR18DE when loads 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 limited torque at a much lower level.

Intake headers carry the during the engines suck phase from the filter and allow it to be fed into the engine and mixed with fuel.

Shape and flow rate of the air Intake manifold can make a big difference to to fuel atomisation and engine efficiency on the MR18DE.

Many mass produced engine intake manifold are in dire need of a performance upgrade, although some car makers provide reasonably good intake manifold.

Big valve conversions on the MR18DE, doing some 3 or 5 angle valve jobs and porting and head flowing will also boost power, & importantly will raise potential for raising the power increase on other parts.

MR18DE performance cam tips.

Different MR18DE engines respond better to mild camshaft durations so set your engine up on a rolling road.

The map and injectors and fuel pump also will say much on the bhp gains you'll hit.

Extending exhaust or intake durations 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.

Significant air intake, and exhaust improvements on the MR18DE can be made from cam upgrades. Changing the cam profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams normally push up the power throughout the rev band, you could sacrifice a little low down power but high end rpm power will be lifted.

Motorsport cams, push up the high end rpm power 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 optimize your engines power to your usage of the car so for a typical daily driver stick with a mild fast road MR18DE camshaft

Stage 1, 2 and 3 mods for the MR18DE

Stage 1 MR18DE parts:

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

Stage 2 MR18DE parts:

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

Stage 3 MR18DE parts:

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

The MR18DE units are great to work on and we see that there is a growing number of parts and tuning parts out there.
Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Remapping will help unlock the full potential of all the mods 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 power output often rely on the mods you've applied 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 significant power gains.

If your car has forced induction parts are relatively easy and you will discover turbo engines will have stronger components.

There are reliable limits for every engine, with some being very over engineered and some only just able to handle stock power

See where you'll find these restrictions and install better quality crank and pistons to survive the power.

There are many tuners spending a lots of money on turbo charger upgrades on the MR18DE only to have the car throw a rod when it's used in anger.

Big upgraded turbo chargers commonly experience no power at low rpm, and small turbo chargers spool up more quickly but do not have the high rpm torque gains.

Thanks to progress the range of turbo chargers is always developing and we commonly find variable vane turbo chargers, allowing 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 feed these at differently profiled vanes in the turbocharger. They also increase 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 get working. We have this guide to twinchargers if you want to read more.

Tips about fuel supply on the MR18DE

When you lift the bhp and torque you will need to look at to the fuelling.

More bhp and torque needs more fuel. At this point we flag up the need to be generous with your injector capacity.

As a rule of thumb add 20% to the flow rate when fitting an injector, this takes into account injector deterioration and provides you some spare capacity should the engine require 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 boost your exhaust system with an upgraded one is if the current exhaust is actually creating a flow problem.

On most factory exhausts you should find that the flow rate is fine 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.

Sports exhausts equal out the flow of gases through the engine.

But if the exhaust pipe is too big, ie: it's over two and a half inches diameter, you will lose much of the exhaust flow rate and end up losing power and torque.

The usual suspects causing problems in your exhaust flow rate can be located the filters installed, so adding a faster flowing performance alternative will help avoid this restriction.

Cat bypassing (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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