Subaru EZ36 Tuning

"All you need to know about tuning the Subaru EZ36 engine!"

The first thing an EZ36 engine owner asks us is how to get more power from my engine.

It is a great reliable solid block, probably more designed for reliability than performance, which means there is a lot of headroom to work in.

Our aim here is to review and look at EZ36 tuning and summarise the ultimate modifications.

Subaru EZ36's make awesome project engines and with the ultimate performance tuning mods like remaps, turbo kits and camshafts you will dramatically improve your driving fun.

History, Power & Specs of the EZ36 Engine

EZ36

191 kW 260 PS 256 hp @6,000 RPM 335 Nm 247 lbft @4,400 RPM

  • ¬†Tribeca 2008
  • ¬†Legacy 2010
  • Outback 2010

Tuning the Subaru EZ36 and best EZ36 performance parts.

Best EZ36 tuning parts

The best EZ36 upgrades on an engine are typically the ones that give the best value for money.

We won't be swayed by popular EZ36 upgrades, they need to be cost effective.

Significant gains on the EZ36 can be made from camshaft upgrades. Altering the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the torque and power output.

Fast road camshafts tend to raise the torque throughout the rev range, you might lose a little low end torque but the higher rpm power will be higher.

Motorsport camshafts, raise the higher 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 because low end power will be very lumpy. Competition cams are designed for maximum power at the top end of the RPM range, a place that most daily commutes will not permit!

You should ideally optimize your bhp range to your preferences so for a typical daily driver stick with a shorter duration EZ36 camshaft

Some EZ36 engines respond better to mild cam durations so set your engine up on a rolling road.

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

Altering valve 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.

Typical stage 1 mods often include: Panel air filters, Remaps/piggy back ECU, Fast road camshaft, drilled & smoothed airbox, Sports exhaust manifold, Intake headers.

Typical stage 2 mods often include: Ported and polished head, induction kit, fuel pump upgrades, high flow fuel injectors, Fast road cam, Sports catalyst & performance exhaust.

Typical stage 3 mods often include: Competition cam, Adding or Upgrading forced induction (turbo/supercharger), Internal engine upgrades (head flowing porting/bigger valves), Crank and Piston upgrades to alter compression, Twin charging conversions, Engine balancing & blueprinting.

Carefully think through your options and then find your mods and set yourself a power target to avoid wasting your time and money.

A remap should help to fully realize the full potential of all the parts you've done to your EZ36.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage may differs on the parts you've fitted and the condition of your engine.

Forcing fuel and air into the EZ36 engine is the main goal to any engine tuning task.

Intake carry the air from the air cleaner and allow it to be sucked into the engine and mixed with fuel.

The size of bore and shape and flow rate of the Intake headers can make a substantial difference to to fuel delivery on the EZ36.

It's not uncommon that plenum chambers are in dire need of motorsport parts, although a few manufacturers provide reasonably good plenum chambers.

Adding a EZ36 larger valve kit, doing some EZ36 port enlargement and head flowing will also improve torque, this will make space for a better torque increase on other upgrades.

EZ36 Turbo upgrades

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your 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 excellent power gains.

If the engine is turbocharged, mods are relatively easy and you will discover turbo engines are made with better components.

However engines will have power limits.See where you'll find these limits and install higher quality crank and pistons to handle the power.

There are many people spending a lot of money on turbo upgrades on the EZ36 only to have the whole thing go up in smoke on it's first outing after it's first rolling road session.

Larger capacity turbochargers commonly experience a bottom end lag, and low capacity turbochargers spool up quickly but won't have the peak end torque gains.

We are pleased that the choice of turbo chargers is always developing and we commonly find variable vane turbo chargers, permitting the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbo chargers divert the exhaust flow into a couple of channels and flow these at differently designed vanes in the turbocharger. They also help the scavenging effect of the engine.

It is common that there is a limit in the air flow sensor MAF/MAP on the EZ36 when considerably more air is being sucked into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting torque at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although harder to get working. We have this article on twincharging if you want to read more.

Fuelling

You will need to ensure that the engine is not starved of fuel so should look at the fuelling when you start going beyond 20% of a bhp increase.Don't forget to over specify your flow rate on the injectors.

As a rule of thumb add another 20% when fitting an injector, this accounts for injector deterioration and affords a bit of spare capacity should the engine need more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

EZ36 Performance Exhausts

You should look to upgrade your exhaust if the current exhaust is creating a restriction.

On most factory exhausts you should find that your flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will 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 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Typically exhaust restrictions can be located the catalysts installed, so adding a freer flowing performance catalyst removes the restriction. We note that performance cats perform similarly to decats and have the added benefit of keeping your car street legal, as decats or catalyst removal is illegal in most territories for road going cars.

Weak spots, Issues & problem areas on the EZ36

The EZ36 engines are generally reliable and solid as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the EZ36, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your EZ36 engine please join us in our friendly forum where you can discuss EZ36 tuning options in more detail with our EZ36 owners. It would also be worth reading our unbiased Subaru tuning articles to get a full grasp of the benefits and drawbacks of each modification.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which parts work best for them on each model of car. Comments are used to improve the accuracy of these EZ36 articles which are continually updated.

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