The EJ255 and the EJ257 are both turbocharged 2.5-liter Subaru EJ-series boxer four-cylinder engines. In the US, the EJ255 powered the 2006-2014 WRX, the Forester XT and the Legacy GT, while the EJ257 was the higher-output version built for the WRX STI from 2004 to 2021. They share the EJ25 architecture, which is why many aftermarket EJ25 short blocks are listed for both, but they are not identical, so match the replacement to your engine code and model year.
EJ255: WRX, Forester XT and Legacy GT
The EJ255 is the turbocharged 2.5-liter used across several US Subaru models, including the 2006-2014 WRX, the Forester XT and the Legacy GT. It is set up for everyday drivability in those cars rather than for the STI’s output.
EJ257: the STI engine
The EJ257 was the engine of the US-market WRX STI for its whole EJ-powered run, from 2004 to 2021. It was developed for the STI’s higher output, so its turbocharger, engine calibration and some internal components differ from the EJ255’s. Details changed over the years, so check the specifications for your exact model year.
EJ255 vs EJ257 at a glance
| Factor | EJ255 | EJ257 |
|---|---|---|
| Layout | 2.5L turbocharged flat-four (EJ series) | 2.5L turbocharged flat-four (EJ series) |
| Main US applications | 2006-2014 WRX, Forester XT, Legacy GT | 2004-2021 WRX STI |
| Built for | Everyday turbo models | The STI’s higher output |
| Block design | Open deck from the factory | Open deck from the factory |
Can you put an EJ257 in a WRX?
Swaps between the two are common in the Subaru community because they share the EJ25 layout, but a swap is more than bolting in a block: the turbocharger, intake, fuel system, wiring and engine calibration all have to suit the engine and the car, and the work has to keep the vehicle’s emissions equipment working. Get the plan from a Subaru specialist before buying parts.
Choosing a replacement EJ25 block
- Match the application: the model years each block fits are in its listing name; many cover WRX, STI, Forester XT and Legacy GT years.
- Factory or closed deck: builds aiming well beyond stock boost often use a closed deck block. See closed deck vs open deck.
- Short block or long block: a long block adds the cylinder heads and valvetrain. See short block vs long block.
Examples we carry include the IAG 1150 Series EJ25 short block. See every option on our Subaru EJ25 short blocks and long blocks page.
More guides: timing belt · EJ257 problems · WRX exhaust sound · what is a boxer engine? · WRX vs STI · EJ25 problems · EJ257 specs · FA20 vs EJ25.
Shipping is a flat $80.00 per order to US addresses, with 15-day free returns. Questions? Ask a parts specialist.