Modding and performance tuning parts for the Subaru EZ36 engine!

Fully Explore "EZ36 Modifications"

How to modify and upgrade the Subaru EZ36

"Comprehensive guide to performance tuning the Subaru EZ36 engine!"

Our friends at TorqueCars often are seeing threads asking about how to improve the EZ36 from people wanting to know what are the best tips for EZ36 upgrades. So let us look into Subaru EZ36 modifications and outline the best modifications on this great engine and point out some common pitfalls along the way.

The Subaru EZ36 are awesome to work on and with the right modified upgrades like remapping, turbo improvements and camshafts you will positively enhance your driving opportunities.

Here we outline options for your EZ36 tuning and highlight the best modifications for your car.

When talking about the ultimate parts for your EZ36 engine, we are going to focus on the upgrades that give the best power gain for you spend.

EZ36 induction kits

Improving air intake on the EZ36

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

So the aim to any tuning job to feed more fuel and air into your EZ36 but this has a knock on effect with the air flow sensor.

You'll commonly see there's a limit in the air flow sensor MAF/MAP on the EZ36 when a lot more air is being sucked into the engine.

When tuning you may well find you need to get an air sensor or flow meter capable of upto 4 bars to cope with quite large power gains, whereas the OEM air sensor was restricting torque at a much lower level.

Intake flow the air from the intake filter and allow it to be fed into the engine cylinders.

The shape and rate of flow of the Plenum can make a noticeable change to fuel mixing and power on the EZ36.

Many mass produced engine intake headers are ripe for aftermarket tuning parts, although some makers provide decently flowing intake headers.

Big valve conversions on the EZ36, carrying out 3 or 5 angle valve jobs and porting and head flowing will also increase performance, & importantly will give you a better performance increase on other parts.

EZ36 performance cam tips.

Each engine responds better to mild camshaft durations so view each engine as unique.

The ECU mapping and fuelling also have a large bearing on the power gains you'll get.

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.

Altering your EZ36 cam will make a dramatic difference to the engine engines power. Choosing a higher performance cam profile raises the engines power accordingly.

NB: Fast road camshafts commonly increase the torque over the rpm range, you may sacrifice a little bottom end torque but top end will improve.

Race camshafts, increase the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a car used daily you need to optimize your engines power to your preferences.

I'd be shocked if you have found a EZ36 Race camshaft is a pleasure to live with when driving in heavy traffic.

Stage 1, 2 and 3 mods for the EZ36

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 EZ36 parts:

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

Stage 2 EZ36 parts:

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

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

Stage 3 EZ36 parts:

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

Carefully think through your options and then buy your parts and set yourself a power target to avoid disappointment.

ECU flashing helps release the full potential of all the parts you've done to your EZ36.

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 the outcome usually differs on the parts you've fitted and the condition of your engine.

Turbo modifications on the EZ36

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 EZ36.

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 a car is turbocharged, mods are giving better power gains and turbo charged engines are built using strengthened components.

However most engines have limits

We recommend you find these limitations and install better pistons and crank to handle the power.

It's not unheard of tuners spending a loads on turbo charger upgrades on the EZ36 only to experience the engine literally blow up when it's used in anger.

Bigger turbos commonly suffer no power at low rpm, and smaller turbos spool up more quickly but don't have the top end bhp gains.

In the last 10 years the selection of turbo units is always moving on and we are seeing variable vane turbo units, permitting the vane profile is altered according to speed to lower lag and increase top end bhp.

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

Tips about fuel supply on the EZ36

Don't dismiss the need ramp up the fuel system when you are increasing the performance - it makes the car more thirsty. Don't forget to over specify your injector capacity.

As a rule of thumb add 20% capacity when specifying an injector, this accounts for injector deterioration and allows 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 EZ36 performance exhaust upgrades

You only need to to upgrade your exhaust system with an upgraded one is if the existing exhaust is actually creating a restriction in flow.

On most factory exhausts you'll find your 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.

Sports exhausts can help increase the flow of air through the engine.

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

Typically exhaust restrictions are in the catalysts installed, so adding a higher flowing sports 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 EZ36

Like most engines an EZ36, 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 EZ36, failure to do this will exacerbate engine wear, on a tuned EZ36 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 EZ36 why not pop over to the forums at TorqueCars where you can chat about EZ36 tuning options and read about others projects who may be planning to do similar modifications on their EZ36.

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