The FA20 and the FA24 are both Subaru FA-series boxer four-cylinder engines; the FA20 displaces 2.0 liters and the FA24 2.4 liters. The naturally aspirated FA20 powered the 2013-2020 Subaru BRZ and its Toyota twins, and a turbocharged FA20 powered the 2015-2021 WRX. The FA24 replaced them: naturally aspirated in the 2022-on BRZ and Toyota GR86, and turbocharged in the 2022-on WRX. Blocks are not interchangeable between the two, so match the engine code to your car.
FA20: BRZ, 86 and the 2015-2021 WRX
The naturally aspirated FA20 was used in the first-generation Subaru BRZ, Scion FR-S and Toyota 86. The turbocharged, direct-injected FA20 (often written FA20DIT) powered the 2015-2021 WRX.
FA24: the 2.4-liter successor
The FA24 increased displacement to 2.4 liters. The naturally aspirated FA24 powers the second-generation BRZ and the Toyota GR86 from 2022, and a turbocharged FA24 powers the WRX from the 2022 model year.
FA20 vs FA24 at a glance
| Factor | FA20 | FA24 |
|---|---|---|
| Displacement | 2.0 liters | 2.4 liters |
| Naturally aspirated use | 2013-2020 BRZ, FR-S and 86 | 2022-on BRZ and GR86 |
| Turbocharged use | 2015-2021 WRX | 2022-on WRX |
Are FA20 and FA24 parts interchangeable?
Not as a rule. The FA24 is a larger-displacement engine, so its block, crankshaft, pistons and many related parts are specific to it, and the naturally aspirated and turbocharged versions of each engine differ too, from the intake and fuel system to the engine calibration. Treat each combination of engine code and model year as its own part number, and confirm fitment before ordering rather than assuming a part carries over.
Naturally aspirated or turbocharged block?
A block for a turbocharged WRX and a block for a naturally aspirated BRZ or 86 are built for different jobs, even within the same engine family. Turbocharged builds aiming beyond stock boost are where closed deck blocks and forged internals come in; a naturally aspirated build usually focuses on compression and revs instead. Tell us your car, model year and goals and we will point you to the listings that fit.
Which block do you need?
Start with the model year and confirm the engine code before you order, because the two engines and their naturally aspirated and turbocharged versions use different parts. Each block we list names the cars and years it fits. Builders planning much more power than stock often choose a closed deck short block, and short block vs long block explains how complete each option is.
Examples we carry include the IAG 1000 Series FA20 closed deck short block for the 2015-2021 WRX. See every option on our Subaru FA20 and FA24 short blocks and long blocks page.
More guides: BRZ exhaust and the FA20 torque dip · what is a boxer engine? · WRX vs STI · FA20 problems · FA20 and FA24 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.