Modding uprating the Subaru EJ16 engine!

All you need to know about "EJ16 Modifications"

EJ16 Modifications Guide

How to modify and upgrade the Subaru EJ16

"Comprehensive guide to tuning the Subaru EJ16 engine!"

Sites like TorqueCars are frequently getting messages requesting info on how to improve the EJ16 from people wanting to know what are the best tips for EJ16 modifications. So let us look into Subaru EJ16 parts and outline the best mods that work on this great engine and point out some common pitfalls along the way.

The Subaru EJ16 provide a fun base for your project and with carefully chosen motorsport modifications like remapping, turbo improvements and camshafts you will positively maximise your driving fun.

Let us look at EJ16 tuning and point out the best modifications for your car.

When talking about the ultimate parts for your EJ16 engine, we are going to focus on the tuning parts that give the best value for money.

EJ16 induction kits

Improving air intake on the EJ16

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

So Pulling fuel and air into the EJ16 engine is vital to any engine performance tuning task.

It is common that there is a restriction in the air flow sensor AFM/MAF on the EJ16 when considerably more air is being drawn into the engine.

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

Intake manifolds carry the air flow during the suck phase from the filter and allow it to be drawn into the engine cylinders.

Structure and flow characteristics of the Plenum can make a substantial effect on to fuel delivery on the EJ16.

I usually find intake are ripe for an upgrade, although some OEM provide fairly well optimized intake.

Larger EJ16 valves, getting port work and head flowing will also lift bhp and torque, this will afford you increasing the bhp and torque increase on other upgrades.

EJ16 performance cam tips.

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

The ecu map and fuelling also have an effect on the bhp gains you'll achieve.

Altering valve 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 EJ16 can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the engines power and power output.

NB: Fast road cams normally raise the power across the rev band, you might lose a little low down power but your higher rpm power will be lifted.

Competition cams, raise the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Race cam is not great driving around busy urban areas.

You should ideally optimize your bhp range to your usage of the car so for a daily driver stick with a fast road EJ16 cam

Stage 1, 2 and 3 mods for the EJ16

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 EJ16 parts:

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

Stage 2 EJ16 parts:

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

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

Stage 3 EJ16 parts:

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

The EJ16 units respond well to upgrades and thankfully there are quite a few choices of upgrades and tuning parts out there.

Remapping will help unlock the full potential of all the tuning mods you've done to your EJ16.

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 often rely on the tuning mods you've carried out and the condition of your engine.

Turbo modifications on the EJ16

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 EJ16.

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 is fitted with a turbocharger upgrades are going to make more power and you'll see that turbo charged engines are made using harder and stronger components.

However you will find an engines have weakspots

Research these limitations and upgrade to higher quality crank and pistons to cope with the power.

There are many guys spending a fortune on turbo upgrades on the EJ16 only to suffer the indignity of watching the motor go up in smoke just after it's used on the roads.

Big upgraded turbo units tend to suffer no power at low rpm, and small turbo units spool up more quickly but don't have the high rpm torque gains.

Thanks to progress the world of turbos is always increasing and we commonly find variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end torque.

Twin scroll turbos divert the exhaust gases into a couple of channels and feed these at differently angled vanes in the turbo charger. They also help 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 gains, although more difficult to setup. We have this feature on twinchargers if you want to read more.

Tips about fuel supply on the EJ16

When you raise the bhp you will need to increase to the fuelling.

More bhp needs more fuel. We would recommend you to over specify your injectors flow rate.

As a rule of thumb add another 20% when buying an injector, this accounts for injector deterioration and provides a bit of 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 EJ16 performance exhaust upgrades

The only time you should look to increase your exhaust system with an upgraded one is if your current exhaust is actually creating a restriction in flow.

On most factory exhausts you'll find your 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.

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

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

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

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

Faults issues and things to look out for on the EJ16

Like most engines an EJ16, 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 EJ16, failure to do this will exacerbate engine wear, on a tuned EJ16 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 EJ16 why not pop over to the forums at TorqueCars where you can chat about EJ16 tuning options and read about others projects who may be planning to do similar modifications on their EJ16.

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