The EJ25 and FA20 are the two turbocharged Subaru boxer engines most people compare. The 2.5-liter EJ25 powered the 2006 to 2014 WRX as the EJ255 and the STI as the EJ257 through 2021; the 2.0-liter FA20DIT replaced it in the 2015 to 2021 WRX. The FA20 is the more modern design, with direct injection and a timing chain, while the EJ25 has a huge aftermarket and a long build history. The EJ25 is known for ringland and head gasket failures; the FA20DIT for issues such as intake valve carbon buildup.
FA20 vs EJ25 at a glance
| EJ25 (EJ255 / EJ257) | FA20DIT | |
|---|---|---|
| Displacement | 2.5 L | 2.0 L |
| Cars | 2006-2014 WRX, STI through 2021 | 2015-2021 WRX |
| Fuel injection | Port | Direct |
| Cam drive | Timing belt | Timing chain |
| Known issues | Ringland failure, head gaskets, rod bearings | Intake valve carbon, other issues covered in FA20 problems |
Is the FA20 more reliable than the EJ25?
Each has its own weak points, and how the car has been driven and modified matters more than the engine code. The EJ25’s most widely reported failures are cracked ringlands under detonation, head gasket leaks and rod bearing failures; see EJ25 problems, EJ257 problems and Subaru head gasket and ringland failure. The FA20DIT’s direct injection means carbon can build up on the intake valves, among other issues; see FA20 problems.
Maintenance differences
- Timing: the EJ25’s timing belt needs replacing at the interval in the maintenance schedule; the FA20’s chain does not have a set replacement interval.
- Oil: both need the right oil and a level kept full; EJ engines in particular can starve oil when low; see Subaru oil pickup tube.
- Intake valves: the FA20DIT can need periodic carbon cleaning.
Building one
Both have strong aftermarket support, and built blocks with closed or reinforced decks are common for higher power; see closed deck vs open deck and forged vs cast pistons. Examples we list include the IAG 1150 Series EJ25 Short Block ($9,499.99), the Turn In Concepts Stage 3+2 Track Closed Deck EJ257 Short Block ($6,799.00) and the IAG Performance 1000 Series FA20 Closed Deck Short Block for the 2015-2021 WRX ($6,999.99).
Can you swap one for the other?
Not easily. Engine management, wiring, intake and turbo plumbing differ between generations, so a swap is a major project. Replacing like with like is far simpler.
Related
See FA20 vs FA24, EJ255 vs EJ257, WRX generations, FA20 specs, EJ257 specs, and the blocks on EJ25 engines and FA20 and FA24 engines.
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