Next Subaru WRX STI Aims to Top 400 Horsepower

Matt Posky
by Matt Posky

Subaru plans on delivering the goods in 2021 when it debuts the next incarnation of its flagship performance model. Rather than incrementally improving the WRX line as it has in the past, Subie looks to be kicking down the stable doors to drag as many horses as possible back to the factory for canning beneath the WRX STI’s hood.

A recent report from Forbes claims Subaru’s engineering team has targeted a minimum of 400 horsepower and 361 lb-ft of torque for the next STI. While the outlet initially referenced the motor as entirely new, it later clarified that it was technically the same 2.4-liter FA24 that currently powers the brand’s Ascent crossover — and was already assumed be adapted for use on the next WRX among those paying close attention. However, it’ll have to undergo quite a bit of work to deliver the figures being claimed.

In the Ascent, the turbocharged boxer produces 260 hp and 277 lb-ft; fine for taking the kids to school, but perhaps lackluster to those more concerned with quarter mile times or blazing up a mountain trail faster than anyone else. Subaru will undoubtedly have to engage in aggressive tuning and adopt stronger engine components to get there.

From Forbes:

In next-generation WRX STI spec however, that same FA24 engine will receive significant upgrades to achieve that smoking hot figure of 400 hp. According to our source, the reworked FA24 in STI spec will employ a reinforced crankshaft and pistons, optimized timing balance, fine-tuned valves and intake ports, boost pressure will be tweaked and brake capacity will be enhanced, among other modifications. And married to the brand’s tried and proven symmetrical full-time 4WD system, expect nothing less than class-leading performance and handling.

In creating the new more powerful STI engine, Subaru engineer’s apparently benchmarked the Mercedes-AMG 2.0-liter turbo — as found in the A45 and CLA45 — which pumps out 416 hp and 369 lb-ft of torque. This engine is currently recognized as the most powerful 2.0-liter series-production four-cylinder engine on the planet.

The big question for yours truly is what this means for the regular WRX. The FA24 has already migrated into other models, so it’d be surprising not to see it in the more street friendly model. Earlier rumors suggested the STI would have the mill running somewhere near 315 hp (barely more than it makes now). Those figures may have been intended for the WRX if the reporting from Forbes is true.

True to form, Subaru has been impressively cagey about any details relating to either car. We can’t really do more than speculate. Still, there’s been enough amped-up FA24 news for us to feel confident about it debuting in the STI in 2021… and lots of conflicting information before that. In 2017, UK marketing director Chris Hawken indicated a hybrid powerplant was under consideration for both WRX models; previous quotes from Subaru indicated the motor was developed to prioritize torque and efficiency over horsepower. While heaps of torque seems equally agreeable, early indications had us believing this wasn’t the unit the company had in mind for its most exciting models.

Regardless, the Japanese-spec EJ20 will be able to retire with the American-spec EJ25 remaining in service until Subaru is ready (presumably very late 2021 or early 2022). Visually, all future WRX models are supposed to take their cues from the various Viziv concepts revealed over the past few years. That procession began at the 2017 Tokyo Motor Show. Lately, we’ve seen more realistic versions earn their time in the spotlight. Considering the model’s design history, it might never have mattered what it looked like. WRX drivers aren’t known for being bastions of good taste or caring about what others think. They’re typically much more interested in math, specifically as it relates to their own car.

We imagine they’ll be pleased if Subaru starts throwing out big numbers, even if the car itself isn’t a looker.

[Images: Everyonephoto Studio/Shutterstock; Subaru]

Matt Posky
Matt Posky

A staunch consumer advocate tracking industry trends and regulation. Before joining TTAC, Matt spent a decade working for marketing and research firms based in NYC. Clients included several of the world’s largest automakers, global tire brands, and aftermarket part suppliers. Dissatisfied with the corporate world and resentful of having to wear suits everyday, he pivoted to writing about cars. Since then, that man has become an ardent supporter of the right-to-repair movement, been interviewed on the auto industry by national radio broadcasts, driven more rental cars than anyone ever should, participated in amateur rallying events, and received the requisite minimum training as sanctioned by the SCCA. Handy with a wrench, Matt grew up surrounded by Detroit auto workers and managed to get a pizza delivery job before he was legally eligible. He later found himself driving box trucks through Manhattan, guaranteeing future sympathy for actual truckers. He continues to conduct research pertaining to the automotive sector as an independent contractor and has since moved back to his native Michigan, closer to where the cars are born. A contrarian, Matt claims to prefer understeer — stating that front and all-wheel drive vehicles cater best to his driving style.

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  • Agyynkhan Agyynkhan on Feb 26, 2020

    I love numbers and always as an amusement, and more seriously than that, invented new algorithms to Standard Deviation Calculator them.

  • GregLocock GregLocock on Feb 26, 2020

    "smoking hot figure of 400 hp. According to our source, the reworked FA24 in STI spec will employ a reinforced crankshaft and pistons, optimized timing balance, fine-tuned valves and intake ports, boost pressure will be tweaked and brake capacity will be enhanced, among other modifications. " So other than dialling up the boost pressure by 15 psi (WAG), none of the other changes will be worth 15 hp.

  • Zipper69 "The worry is that vehicles could collect and share Americans' data with the Chinese government"Presumably, via your cellphone connection? Does the average Joe in the gig economy really have "data" that will change the balance of power?
  • Zipper69 Honda seem to have a comprehensive range of sedans that sell well.
  • Oberkanone How long do I have to stay in this job before I get a golden parachute?I'd lower the price of the V-Series models. Improve the quality of interiors across the entire line. I'd add a sedan larger then CT5. I'd require a financial review of Celestiq. If it's not a profit center it's gone. Styling updates in the vision of the XLR to existing models. 2+2 sports coupe woutd be added. Performance in the class of AMG GT and Porsche 911 at a price just under $100k. EV models would NOT be subsidized by ICE revenue.
  • NJRide Let Cadillac be Cadillac, but in the context of 2024. As a new XT5 owner (the Emerald Green got me to buy an old design) I would have happy preferred a Lyriq hybrid. Some who really like the Lyriq's package but don't want an EV will buy another model. Most will go elsewhere. I love the V6 and good but easy to use infotainment. But I know my next car will probably be more electrified w more tech.I don't think anyone is confusing my car for a Blazer but i agree the XT6 is too derivative. Frankly the Enclave looks more prestigious. The Escalade still has got it, though I would love to see the ESV make a comeback. I still think GM missed the boat by not making a Colorado based mini-Blazer and Escalade. I don't get the 2 sedans. I feel a slightly larger and more distinctly Cadillac sedan would sell better. They also need to advertise beyond the Lyriq. I don't feel other luxury players are exactly hitting it out of the park right now so a strengthened Cadillac could regain share.
  • CM Korecko Cadillacs traditionally have been opulent, brash and leaders in the field; the "Standard of the World".That said, here's how to fix the brand:[list=1][*]Forget German luxury cars ever existed.[/*][*]Get rid of the astromech droid names and bring back Seville, Deville, Eldorado, Fleetwood and Brougham.[/*][*]End the electric crap altogether and make huge, gas guzzling land yachts for the significant portion of the population that would fight for a chance to buy one.[/*][*]Stop making sports cars and make true luxury cars for those of us who don't give a damn about the environment and are willing to swim upstream to get what we really want.[/*][*]Stop messing around with technology and make well-made and luxurious interiors.[/*][*]Watch sales skyrocket as a truly different product distinguishes itself to the delight of the target market and the damnation of the Sierra Club. Hell, there is no such thing as bad publicity and the "bad guy" image would actually have a lot of appeal.[/*][/list=1]
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