If you are comparing the FA20 and FA24 engines found in modern Subaru WRX models, you are not alone. With the introduction of the FA24 in the 2022 WRX, many owners are wondering how it compares to the earlier FA20, especially when it comes to reliability, tuning, and modification potential.
This guide breaks down the key differences in simple terms to help you understand what sets these engines apart and which one may better fit your goals.
FA20 Overview (2015–2021 WRX)
The FA20DIT powered the WRX from 2015 through 2021. It is a 2.0-liter turbocharged, direct-injected engine that quickly became popular thanks to its strong aftermarket support and proven tuning platforms.
Over the years, the FA20 has been extensively modified, tuned, and rebuilt by enthusiasts and shops alike, making it one of the most well-understood modern Subaru engines. You can explore supporting components under EFI Tuning and Forced Induction categories.
Why the FA20 Is Still Popular
- Large aftermarket support with proven parts
- Well-documented tuning strategies
- Wide range of short block and long block options
- Strong community knowledge around common upgrades
FA24 Overview (2022+ WRX)
The FA24DIT debuted in the 2022 WRX as a 2.4-liter turbocharged engine. While it shares the FA family name, it brings notable changes, including increased displacement and a different torque delivery compared to the FA20.
From the factory, the FA24 focuses more on low-end torque and drivability rather than peak horsepower, which changes how the car feels in everyday driving. Many early upgrades are centered around the COBB Tuning ecosystem as well as growing engine solutions from IAG Performance.
What Makes the FA24 Different
- Larger displacement for improved low-RPM torque
- Smoother power delivery in stock form
- Newer platform with growing aftermarket support
- Different tuning considerations compared to the FA20
Reliability and Daily Driving
Both the FA20 and FA24 can be reliable daily drivers when properly maintained and tuned. The key factor is not the engine itself, but how modifications are planned and executed.
The FA20 has the advantage of time. Common weak points, safe power levels, and supporting modifications are well understood. The FA24, while newer, has shown promising reliability so far, especially for lightly modified daily-driven setups.
Modding and Tuning Differences
From a modification standpoint, the FA20 offers more immediate options simply due to the depth of available parts and long-term tuning data.
That said, the FA24 is quickly catching up. Flex fuel upgrades and tuning solutions are already available, and engine build options are beginning to expand. Many builds also require supporting upgrades in Fuel Delivery systems to safely handle ethanol blends and higher boost levels.
Examples of common upgrade paths include:
- FA20 Flex Fuel Upgrades for 2015–2021 WRX models
- FA24 Flex Fuel Upgrades for 2022+ WRX models
Engine Build and Upgrade Options
When it comes to internal engine upgrades, the FA20 currently has far more established options. Built short blocks and long blocks are widely available for a range of power goals, from moderate street builds to fully built track-focused engines.
The FA24 is newer to the performance market, but high-power solutions are already emerging for owners planning more serious builds under the broader Engine Components category.
For EJ-based Subaru builds or higher horsepower conversions, closed-deck IAG short blocks are the proven upgrade path for owners targeting significantly higher horsepower levels. Our IAG short block guide for WRX and STI breaks down every option and what power level each one is built for.
These upgraded short blocks are engineered to handle higher boost pressures, increased cylinder pressure, and the additional stress created by larger turbochargers and aggressive tuning strategies.
- Browse Subaru Short Block Options
- Explore Performance Engine Mounts for WRX & STI builds
- Shop Performance Exhaust Systems
For EJ25 builds targeting serious power levels, our IAG short block guide for WRX and STI covers the full range from street-focused options up to extreme high-boost builds. FA24 owners planning a built engine will find dedicated options covered there as well.
Planning an Engine Build?
If you’re planning a higher-horsepower FA20 or FA24 build, selecting the right short block and supporting components is critical to long-term reliability and safe power delivery.
Not sure how much power your stock engine can safely handle before a build becomes necessary? Our FA20 and FA24 stock power limits guide covers safe horsepower ranges and when upgrading to a short block makes sense.
Supporting Mods for Higher Power Builds
As power levels increase through turbo upgrades, ethanol fueling, or built engines, supporting components become increasingly important. Many WRX and STI builds combine reinforced engine mounts with improved airflow components such as performance exhaust systems to support higher horsepower setups. Managing crankcase pressure with solutions like IAG oil catch cans and AOS systems also becomes critical under higher boost conditions.
For builds targeting significantly higher power levels, upgrading the turbocharger becomes a common next step. Larger units such as the Boost Lab TD06SL2 turbocharger are designed to move more air and support builds approaching the 500 horsepower range when paired with proper fueling and engine internals.
Combining proper airflow upgrades with stronger engine internals and reliable tuning helps ensure the engine can safely handle increased boost pressure and horsepower targets.
FA20 vs FA24: Frequently Asked Questions
Is the FA24 better than the FA20?
The FA24 offers more displacement, improved low-end torque, and smoother power delivery in stock form. However, the FA20 has a deeper aftermarket ecosystem and more established tuning data. Which is better depends on your goals — the FA24 is the stronger daily driver platform, while the FA20 has more proven high-performance build options.
Can the FA24 handle more power than the FA20?
The FA24 has shown promising results for moderate power builds, and IAG has released closed-deck short block options specifically for it. However, the FA20 currently has more established high-horsepower build paths due to its longer time in the aftermarket. Both engines benefit from built internals when pushing serious power levels.
Is the FA20 or FA24 more reliable?
Both engines are reliable when properly maintained and tuned conservatively. The FA20 has well-documented failure points and solutions developed over years of community use. The FA24 is newer, so long-term reliability data is still developing, but early results for lightly modified builds are positive.
What year did Subaru switch from FA20 to FA24?
Subaru introduced the FA24DIT in the 2022 WRX, replacing the FA20DIT that powered the 2015 through 2021 models. The FA24 brings increased displacement from 2.0 to 2.4 liters along with revised torque characteristics and updated engine management.
Ready to Upgrade Your WRX?
Whether you’re upgrading for flex fuel, planning a built engine, or optimizing your current setup, the right components and tuning strategy make all the difference.
If you are ready to start planning your build, our WRX performance upgrades guide covers every major modification category and how they work together from bolt-ons to full engine builds.
If you plan to increase boost or modify turbo performance, understanding how pressure is controlled becomes important. Our boost control guide explains how WRX and STI turbo systems manage airflow and power delivery.