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EJ20 vs EJ25: Which Engine Should You Use?

Subaru WRX STi close of the engine with EJ20 EJ25 Motore Engine

The EJ20 and EJ25 are just a tiny part of the legendary line of Subaru engines. The models were introduced in the late 80s and early 90s but have impacted the market with their power and efficiency. So which engine should you use, an EJ20 or an EJ25?

The engine numbers on the EJ series can be confusing as there are other indicators for upgrades and fuel delivery. However, you can cut through the confusion and get the necessary information by concentrating on the number you are looking for. So read on and learn all you need about the EJ20 and EJ25 engines and which one to use.

The Differences Between the EJ20 and EJ25 Engines

When comparing a set of items, it is always best to learn what each is capable of and then see which of those capabilities fit your plans for the engine. Take your time and take notes if you need because once the third number identifiers get involved, it can be hard to decipher your engine type without a closer inspection.

The EJ20 has a Long History of Successful Engine Types.

The EJ20 is a Subaru engine produced between 1989 and 2015 and featured in several of its most legendary models. As a result, they were often given a third number or letter designation that denotes the engine’s options. Pay close attention to them, as ignoring them can make you end up with the wrong parts, and nobody wants that trouble.

A few of the most well-known EJ20 engine variants are as follows:

  • EJ 201 – The EJ 201 was placed in the Legacy and Forester between 1998 and 2005 and had a horsepower of 125 to 135, depending on the tuning. These popular engines and models are still on the road today and are still in demand.
  • EJ 202 – The sequel to the 201 ran from 98 to 09 and had an upgrade that featured a lighter engine block. You might have seen these engines in the Forester and Legacy from those years and might have owned one.
  • EJ 203 – Another tremendous EJ20 engine was the EJ 203. It was found in the second production of Forester and had an electronic throttle. In addition, EJ models can have turbochargers; these models were some of the first to reap the benefits.
  • EJ 20E – There’s always an oddball in the group; in this case, it is the EJ 20E. It was in the Impreza and Legacy from 89 to 11 and what made it so odd is that models in other countries, like Japan, have different specs and compression ratios.
  • EJ 204 – In the Forester and Impreza from 1999 until 2015, was a solid EJ20. The EJ 204 came equipped with several options over its career and even had an electronic control unit that allowed you to control the camshaft gears.

The EJ20 has been around for several years and has been in all the main offerings from Subaru. The 20 is the smaller of the two engines, but that doesn’t mean it doesn’t perform well. These engines are efficient and dependable, allowing some users to keep their 98 Foresters on the road with general maintenance alone.

The Specifications of the EJ20 are Impressive

When you dig around in the specs of the EJ20, you begin to notice why it was adapted into so many sub-models and had many options. The power and torque you get from the newer models are exciting and have increased interest in off-road and street racing. The EJ20’s strength and stability make it unique, and seeing the numbers only begins to do it justice.

Subaru WRX STI white hatchback powered by the EJ20 motor engine
Subaru WRX STI hatchback powered by the EJ20 engine

Some of the specifications of the EJ20 engine are as follows:

  • Horsepower – Four-cylinder cars don’t spring to mind when you talk about horsepower, but pound for pound, these dynamo engines can hold their own. The most powerful EJ20s is the 204, which has 190 horses at peak performance. On the low end, the European model of the 203 has a steady 115hp.
  • Torque – Another big thing people want to know about the EJ20 engines is how much torque they can produce. Torque is necessary when racing to close the cap on competitors or catch a light before it turns red. The Torque for the EJ20 ranges from 165 to 200 horsepower.
  • Odds and Ends – You wouldn’t think this type of power is available in an engine that only weighs 120 pounds, but five models have the larger engine block. The displacement is 1994cc, while the fuel systems are fuel injected. The blocks are made from aluminum which makes them light and durable.

When you look at the specifications, it isn’t hard to understand why people love driving the Subaru with the EJ20 engines. They are easy to find, and with the information on the internet, you could easily make repairs and do the maintenance yourself.

The EJ25 Models are a Powerful Engine With Endless Potential

When you think about the types of EJ engines and their codes, it is best to remember that the first two numbers are the displacement amounts, and the following number or letter is the signifier that tells you. of the variant type. No matter what type you have, there are a few model numbers you should be on the lookout for.

A few of the variant numbers of the EJ25 engine are as follows:

  • EJ 25D – The first EJ25 engine is the D series model. It came out in the 96 Subaru Legacy, and the D stands for dual overhead cams. It has been redesigned several times, and the dual overhead cam design has remained a constant.
  • EJ 251 – Another single overhead cam design model is the EJ251. This model never got much traction as the SOHC mechanism caused a laundry list of problems that were never fully corrected. The gaskets were constantly leaky, and Subaru moved on to the next model design.
  • EJ 252 – While there are rumors that the 252 was just an alternate molding of the 251, the performance would say otherwise. Released in 1999/2000, the EJ252 started in the Outback and has a bevy of electronic instruments under the hood.
  • EJ 253 – One of the most beloved EJ25 engines is the 253. It has 162hp and 167ft-lbs or torque at around 4400RPMs. The 253 debuted in late 99 and has been in some fantastic Subaru models.
  • EJ 254 – The 254 is the following design variant, with 165hp at 6K RPMs. This model was one of the first to have an active valve control system, which was only available in the EJ20 class of engines.
  • EJ 255 – An EJ 255 is a solid engine that has 261hp at max tuning. 261hp is phenomenal for an engine that is a short block; you will find these in highly sought-after Impreza and Legacy Euro editions.
  • EJ 257 – Used from 2008 to 2010, the EJ257 is one of the best high-performance engines on the market. It has an extensive turbo system and is a dual overhead cam designed engine.

The EJ25 has several variant designs that are hearty dependable engines. They come in all different styles of Subaru from the late 1990s until the mid-2010s. Some have a turbocharger that gives them more horsepower and torque than their cousins.

The Capabilities of the EJ25 Series are Impressive

Seeing what these engines can do on paper isn’t that impressive. What they can do on the track and street as an unassuming soccer mom ride makes them exceptional. By checking the specs, however, you will see that the engines are powerful for their size and critical to the Subaru’s longevity.

Black Subaru WRX STI powered by the EJ25 engine motor
Subaru WRX STI powered by the EJ25 engine

A few of the specs of the EJ25 engine are as follows:

  • Horsepower – The EJ25s strongest motor produces 341hp at 6400RPMs. That’s a strong statement about the power of the engines, and the fact that it only weighs 500 lbs is jaw-dropping. The block is made from aluminum which makes it strong and very light.
  • Torque – Another big thing the EJ25 can do is produce a ton of torque. It has 330 ft-lbs at 3400 RPMs. Torque is essential for climbs in your Outback or pulling a tight curve in your Impreza.
  • Odds and Ends – The engine weight could depend on whether the engine is naturally aspirated or has a turbocharger. The chargers are separate pieces but attached to the engine body like an alternator. This adds extra pounds to the entire casing, not just the engine block.

The things that an EJ25 can do are a step ahead of the EJ20s. They have more horsepower and torque and have been used for much longer. They started service in 1996, and versions of the EJ25 engine are still in use today.

Which Engine Should You Use?

Now that all the cards are on the table and you know what each engine model can do, it is time to move on to the next step, deciding which engine works best for your situation. Again, relying on the facts above, you know what the engine can do. Now you need to determine what it can do for you.

A few uses of the EJ20 and EJ25 Subaru engines are:

  • Off-Roading – The Outback is a fantastic vehicle for light off-roading. If you want to hit the deep mud, think of something much more substantial and full-bodied. The combination of torque and horsepower leans in favor of the EJ25 models if you want to hit the trails.
  • Racing – There are Imprezas out there that do street and off-road racing. If this is your niche, either of the engine models should work just fine for you. However, upgrading the EJ20 could be essential if competing against larger six-cylinder engines.
  • Hauling – Subaru owners love the outdoors. They often have pop-up campers and kayaks that require a trailer to get from home to camp. The Outback has both EJ20 and 25 models, but you should check the weight of your camper. The EJ25 has the most horsepower and torque of the pair.
  • Daily Driver – Subaru drivers love their cars. Having a Sub as a daily driver would mean you have a fuel-efficient, dependable vehicle that can summon a decent amount of power when needed. Either engine works best, but economically the EJ20 will be the engine of choice.

The uses of the EJ20 and EJ25 engines are limitless. They are dependable engines that have few flaws and are easy to work on. Knowing what you want to do with the vehicle and what it can do is sufficient evidence to make an informed decision. No matter which you choose, the ride will be enjoyable and exciting.

Frequently Asked Questions (FAQ)

Q: Do the Subaru EJ20 and EJ25 Engine Have any Major Problems?

A: The biggest problem with the pair is that they can use an excessive amount of oil. Using too much oil puts the engine in danger of overheating and locking up. Not enough oil is a recipe for disaster in any engine, even the EJ20 and 25. In addition, the oil tends to leak out of the seals and onto the driveway.

The most common problem with the engine occurs because one of the cylinders could be too far from the coolant system. As it begins to overheat, the cylinder will start tapping. It will go away once the car warms up, but once it is a constant thing, you will need to replace it. Ask a friend for a mechanic recommendation or begin an internet search in your area.


The EJ20 is a four-cylinder engine produced by Subaru in their plants in Japan. These engines came into service at the dawn of the millennium, and some model variants could be out in traffic today. It is a small but powerful engine that is economical and gas efficient.

EJ25 is larger than the EJ20 and has had a long run in the high-performance and turbocharged editions of Subaru favorites like the Outback and Impreza. They have higher horsepower and torque than the EJ20 but could use more fuel and maintenance costs. Choosing between the two is tough but if you need power, going with the EJ25 is your only option.

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Subaru EJ20 2.0L Engine Specs, Problems & Reliability

Ernest Martynyuk

An automotive enthusiast who's been tinkering with vehicles since I was 15-years old. Repairing automotive electronics has been my main job for over a decade now and have a passion for everything technical regarding cars.

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