Everything You Need To Know About The Subaru EJ257
2.5L flat-four boxer engines are still in use today with the new 2004 Impreza WRX STi models and have been around for many years! The EJ257 is one such example. It made 300 to 341 horsepower when first released back then but now can make up to 50 more thanks to modifications like larger turbochargers or upgraded fuel injectors that give you more excellent performance while not sacrificing reliability at all.
We explore this guide on how to mod your car, so it has even better power than before without any problems along the way.
What Cars Use the EJ257?
The EJ257 can be found in the following cars:
- Impreza WRX STi 2004-current
- Legacy GT 2005-2009
- Forester XT 2004-2006
- Saab 9-2X Aero 2005
Subaru EJ257 Engine Specs
The EJ257 is a prevalent engine, as You can find it in many cars and applications. It has also been heavily upgraded over the years, so now it's even more capable than before. The engine's displacement is 2457 cc, with 76mm bore spacing and 86mm stroke length like most other Subaru flat-four boxer engines.
What Makes the Subaru EJ257 Engine Special?
The turbocharged nature of this engine is unique as most other cars with a forced induction system have a single turbo attached to the exhaust manifold on the opposite side of the machine. In this case, both turbos are on top of each other, which means their combined length creates a straight path for the hot exhaust gasses to flow out from each turbocharger efficiently and quickly.
The bottom line is that those high-performance EJ257 engines can produce much power and torque in a reliable package.
EJ257 Turbo Specs
Subaru produced the EJ257, and they built two variations of the engine with different turbos; one is similar to the previous EJ25D used in the GR models Impreza, while another kind has an even larger TD04-15G turbocharger. Both are good choices as the smaller EJ25D turbos will spool faster but give less total horsepower, while the larger TD04-15G unit has a high peak of power at 5,000 RPMs which is very close to redline on some applications.
Fast forward into 2018, and the boost pressure on the EJ257 has been cranked up thanks to bigger turbochargers. It can now make between 600 to 1,000 horsepower!
EJ257 Engine Block Oil Ports/Cooling
One of the few ways that Subaru engineers chose to cool down this engine is by drilling tiny holes into the top of the block near the exhaust valves. They allow the heat from the engine to slowly transfer into the coolant to properly bring down the temperature of this engine before it is pushed back out during use.
E5J257 E.ngine Head Gasket Design
The design of a Subaru EJ25 head gasket looks very similar to most other 2L four-cylinder engines from Subaru as it has a single layer of steel gaskets with a cell-type design to absorb all the heat that is created during driving.
EJ257 E.ngine Block Design
The EJ257 engine block is made out of very sturdy cast iron and built to withstand a lot of pressure before it ever breaks down. It also has many coolant ports that run along the length of it, which allows for a very even distribution of the liquid to be sent throughout the engine at all times during use.
EJ257 E.ngine H.eretical Design
The Subaru EJ257 engine is very similar to most other 2L 4-cylinder engines. It has an aluminum alloy cylinder head with combustion chambers on top and an iron block where the pistons go up and down to move the car forward or backward while underway!
How many PSI can a Subaru EJ25 hold before it will blow?
When you have a Subaru engine, there are specific rules that you should always follow when making changes to the car. This is because they are built with very durable parts that can withstand many high-performance upgrades. Still, vital components, like the head gasket, can be easily damaged if it doesn't receive enough coolant or oil when underway!
The EJ257 boxer engine was found in many applications, including the latest Subaru BRZ sports car. It came equipped in five different power levels depending on whether the vehicle has one turbo attached to the exhaust manifold or two. If you have two turbos, expect between 300 to 500 horsepower while only receiving up to 280 hp when just using one turbocharger. The important thing here is that this engine has tremendous results, which means plenty of aftermarket support exists upon its release!
How hard is it to install an EJ257 turbocharger?
Adding a turbocharger to your Subaru engine increases the horsepower, but it isn't always easy for everyone. Fortunately, aftermarket companies have created brackets that allow you to easily bolt another piece of equipment onto the car, which is what you need if you want more power!
When building this kind of motor, people often think they can push tons of air through with larger turbos and increased boost levels, but they must remember that there is an excellent line between too much and not enough when it comes to engines like this one!
Common EJ257 Engine Problems
The most common problem with an EJ257 engine is not using the correct type of oil or coolant, so always remember to check what kind of liquids your car needs for this engine to function while out on the open road correctly.
People have other issues: leaking head gaskets, warped exhaust manifolds, and blown engines due to over-boosting the turbocharger! This means all drivers should take care when underway because it can be hazardous if you do not know what you are doing behind the wheel!
How much horsepower will a Subaru EJ25 handle?
Some racers have found ways around this by making their cars lighter. Hence, they still have decent acceleration times, but this requires excellent knowledge about all aspects of suspension tuning. This is why most drivers are just looking for ways to have more fun when taking their Subaru out onto the open road!
How much horsepower will a stock Subaru EJ25 handle?
The Subaru EJ25 engine isn't potent in the car, so many racers want to find different ways to get it working hard by adding aftermarket wheels, suspensions, and turbochargers to increase the power output dramatically. Some people have managed to create over 1000hp with this engine by making more significant amounts of air go through their turbocharger and into the machine, which only makes sense since they come from Japan, where there are roads that require higher speeds than typical American freeways!
What kind of reliability can you expect from an EJ25 engine?
Subaru built the EJ25 engine to last a long time, so you should have no problems with this motor unless you are trying to get massive amounts of power out of it, compromising durability. You can get over 300 horsepower if you use stock components, but anything more than that might cause severe damage!
The performance of an EJ25 turbocharged engine is usually excellent for its price range, and you can get it to work hard if you know how you should modify a Subaru car. Having a vehicle that can handle 1000 horsepower isn't what novice drivers want, but they should keep in mind that many people have managed to get this power out of their cars, so there must be something special about Subaru's EJ25 engine!