Tuners tips on "MR20DD Modifications"

MR20DD Modifications Guide

How to modify and upgrade the Nissan MR20DD

"Comprehensive guide to performance tuning the Nissan MR20DD engine!"

Forums like the one at TorqueCars are always getting emails asking about how to improve the MR20DD from people inquiring about getting more power from the MR20DD and wanting to know what are the best MR20DD modifications. So let us look into Nissan MR20DD modifications and outline the best mods that work on this great engine and point out some frequent tuning mistakes along the way.

Here we examine the options for your MR20DD tuning and report on the best upgrades. Nissan MR20DD make awesome project engines and with carefully picked modified modifications like remapping, turbo upgrades and camshafts you will noticeably maximize your driving opportunities.

Just because particular tuning parts are appear in lots of MR20DD projects it doesn't mean you should fit it, instead we will focus on the greatest tuning parts that will give your MR20DD the biggest power gain return for your cash.

Without us subscribing to the popular 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'.

MR20DD induction kits

Improving air intake on the MR20DD

You need fuel and air for an engine to work. If there is insufficient fuel then it will run lean, if there is little flow of air it runs rich sapping power which risks damage to the MR20DD. 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 tuning task to force more fuel and air into each cylinder but this has a knock on effect with the air flow sensor.

You'll commonly see there is a limit in the air flow sensor AFM/MAF on the MR20DD when loads more air is being pulled into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited performance at a much lower level.

Intake manifolds transmit the air during the suck phase from the air filter and allow it to be fed into the engine cylinders.

Structure and rate of flow of the Plenum can make a substantial effect on to fuel delivery on the MR20DD.

Commonly we find the plenum chambers are in dire need of aftermarket parts, although a few makers provide reasonably good plenum chambers.

Adding a MR20DD larger valve kit, getting MR20DD port enlargement and head flowing will also increase torque, & importantly will raise potential for a better torque increase on other upgrades.

MR20DD performance cam tips.

Each engine responds better to more or less aggressive camshaft durations check your engine on a rolling road.

The map and fuel pump and injectors also have an effect on the torque gains you'll hit.

Extending exhaust or intake 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.

Altering your MR20DD camshaft will make a dramatic difference to the engine bhp. Choosing a higher performance camshaft profile raises the bhp accordingly.

NB: Fast road cams usually push up the power through the rpm band, you could drop a little bottom end torque but your top end will be higher.

Motorsport cams, push up the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a road car you need to optimize your bhp range to your preferences.

I'd never find a MR20DD Race cam is a pleasure to live with when in heavy traffic.

Stage 1, 2 and 3 mods for the MR20DD

Stage 1 MR20DD parts:

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

Stage 2 MR20DD parts:

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

Stage 3 MR20DD parts:

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

The MR20DD engine blocks respond well to upgrades and we're finding that there is an increase of parts and tuning parts around.

A remap should help to release the full potential of all the modifications you've done to your MR20DD.

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 your mileage may vary depending on the modifications you've applied and the condition of your engine.

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Turbo modifications on the MR20DD

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 MR20DD.

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 an engine has forced induction tuning parts are going to net you a larger power gain and you will discover turbo engines are made with harder and stronger components.

However most engines will need better parts at higher power limits

It is important to find these limits and fit better quality components to cope with the power.

We see many car owners spending a loads on turbo upgrades on the MR20DD only to see the car catastrophically fail just after it's completed.

Big turbos will usually experience a bottom end lag, and little turbos spool up much more quickly but do not have the high rpm torque gains.

We are pleased that the range of turbo chargers is always improving and we are seeing variable vane turbo chargers, where the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo chargers divert the exhaust gases into a couple of channels and push these at differently angled vanes in the turbo charger. 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 bhp and torque gains, although more challenging to install. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the MR20DD

When you boost the torque you will need to increase to the fuel system.

More torque needs more fuel. Care modifiers usually say to over specify your injector capacity.

The accepted safe increase is to add 15% when fitting an injector, this accounts for injector deterioration and affords a bit of 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 MR20DD performance exhaust upgrades

You only need to to improve your exhaust system with an upgraded one is if the current exhaust is actually causing a flow problem.

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

Please dont run with the biggest exhaust you can buy you'll 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.

The usual suspects causing problems in your exhaust flow rate can be traced to the emissions filters installed, so adding a freer 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 MR20DD

Like most engines an MR20DD, 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 MR20DD, failure to do this will exacerbate engine wear, on a tuned MR20DD 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 MR20DD why not pop over to the forums at TorqueCars where you can chat about MR20DD tuning options and read about others projects who may be planning to do similar modifications on their MR20DD.

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