Skip to main content

The End Of The EJ25 - A New Subaru WRX STI Era Begins Now

The Subaru WRX STI 2.5-liter Boxer was a good engine, but its days are coming to an end. See why the next-generation STI with a 2.4-liter powerplant will be just what performance fans want.

Join us...    

The next-generation 2023 Subaru WRX STI won't have the EJ25 Boxer engine when it arrives next year. It's the end of an era, and it's a new beginning for the performance car. The EJ25 had its share of problems, and after a failed lawsuit, Subaru is cutting ties with a 2.5-liter engine forever. It's being put on the shelf, and it's not coming back, but that's a good thing for performance enthusiasts.

The EJ25 is out; the FA24 is in

The all-new FA24 2.4-liter turbocharged Boxer will take its place, and a new era of performance will begin. Reports say the all-new next-generation Subaru WRX STI engine will produce around 345 horsepower, which is considerably more than the 2022 WRX's 271 horsepower. That's just speculation, and Subaru, as usual, is being tight-lipped about the next-generation sports car.

2023 Subaru WRX STI, next-generation Subaru STI
The EJ25 Final Edition WRX STI

If Subaru gives the new STI only a three-horsepower increase like the WRX, performance fans will be disappointed. The 2021 Subaru WRX STI's current 310 horsepower is five horsepower behind the Volkswagen Golf R's turbocharged 2.0-liter four-cylinder engine that makes 315 horsepower and 310 lb-ft of torque, up from 288 horsepower and 280 lb-ft in the last generation R.

How does the 2022 Subaru WRX compare with the competition?

The 2022 WRX has 271 horsepower, the Volkswagen Golf GTI is rated at 241 horsepower, Hyundai Elantra N produces 276 horsepower, and the Volkswagen Jetta GLI has a 228-hp engine. Against that lineup, the 2022 WRX compares favorably, and the 2022 Civic Si looks like it is woefully underpowered.

2023 Subaru WRX STI, next-generation Subaru STI
2022 Subaru WRX 2.4-liter Boxer engine

What the STI needs to be the leader

The 2023 STI should set the bar for compact sports cars and be the leader in performance. If a new generation era begins with anything less than the 2023 Subaru WRX STI's new 2.4-liter turbocharged flat-four producing less than 320 horsepower, it will not start well.

Why the FA24 is a good move for the next-generation STI

Subaru made upgrades to the FA24 that powers the Ascent and Outback. The engine block and internals are beefed up to handle the increase in horsepower. In a performance engine, it's even more critical because of the extra boost from the turbocharger. Subaru increased the thickness of the cylinder walls and added larger connecting rods, which are twice as thick as the EJ25 2.5-liter turbocharged engine in the previous generation STI.

Subaru also upgraded the valve springs. The FA24 comes with new" Beehive" valve springs that are smaller at the top and broader in the middle, making them stronger and can handle more pressure and higher revs (500-700) than a typical spring.

For more information on the 2023 Subaru WRX STI FA24 2.4-liter Boxer upgrades, check out the report below. The EJ25 is out; the FA24 is in to begin a new performance era.

You Might Also Like: Will The New Subaru STI 2.4L Engine Be Reliable With Power Upgrades? Why It's The Best Yet For Tuners

Denis Flierl has invested over 30 years in the automotive industry in a consulting role working with every major car brand. He is an accredited member of the Rocky Mountain Automotive Press. Check out Subaru Report where he covers all of the Japanese automaker's models. More stories can be found on the Torque News Subaru page. Follow Denis on Facebook, Twitter, and Instagram.

Subaru Report - We’ve got you covered! Check back tomorrow for more unique, informative SUBARU news, reviews, and previews you can trust.

Leave your comments below, share the article with friends and tweet it out to your followers!

Photo credit: Subaru

Join us...    


Jon (not verified)    November 3, 2021 - 1:01PM

This is the second article I've seen that is supposed to talk about the 2022 STI and suddenly, unexpectedly, jumps to 2023. Are they interchangeable? Why not stick with 2022?

Bob (not verified)    November 3, 2021 - 2:23PM

It's long past due. The STI has had the same motor since 2004, nearly 20 years and only gained 10hp in all that time.

Jason (not verified)    November 4, 2021 - 6:04PM

In reply to by Bob (not verified)

If you look at dyno runs over the years, the STI has actually gained about 40 crank hp since 2004, just not on their spec sheet. But, I don't expect many people to know that. Though, that's been offset with extra weight (especially rotating weight) over the years to keep them from being faster in a straight line. Quite a few vehicles power figures are under-rated these days, just look at any German performance vehicle.

Richard Ruilova (not verified)    November 4, 2021 - 6:19AM

Civic si does not compete with the sti or wrx it never has really unfair comparison two different levels of sports cars si traditionally competes with brz, fiesta ST, etc