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Rumor Mill; Next-Gen Subaru WRX STI Might Get New 2.4-L Turbo

The next-generation 2020 Subaru WRX STI could get a new mill. See what rumors are swirling.

The next-generation Subaru WRX STI could be coming with a new 2.4-liter engine if rumors are correct. According to a report from Road & Track, Subaru could use the new Ascent 2.4-liter turbo Boxer in the fourth-generation Subaru WRX STI replacing the aging EJ25 2.5-liter used in the current model when it arrives sometime in 2020. It’s reported the 2.4-liter turbo could make 330 plus horsepower in the new STI.

Subaru engineers developed the 2.4-liter powerplant for the Ascent 3-Row family hauler. The new FA24 Boxer engine comes with the latest direct injection and other internal upgrades for the best power and towing vs fuel efficiency. Could Subaru drop it in the fourth-generation WRX STI?

It features all-aluminum heads and block, to reduce weight and allows for more rapid warm-up. The internals include heads with dual overhead cams, driven by a timing chain rather than a belt, actuating 16 valves with variable timing.

It has a total engine displacement of 2,387cc with a 94-millimeter bore and an 86-millimeter stroke. The compression ratio is 10.6:1 which keeps cylinder pressures high for efficiency. It also features a twin-scroll turbocharger.

In the Ascent, the new FA24 engine develops 260-horsepower at 5,600 rpm and has a broad peak torque band of 277 lb-ft between 2,000 and 4,800 rpm. Subaru Technica International would rework the internals and bump up horsepower and torque considerably if they use it in the new WRX STI. Subaru could also use it mated with new hybrid technology being developed now.

Of course, this is all speculation and has not been confirmed by Subaru who declined to comment. Subaru needs to replace the aging 2.5-liter EJ25 Boxer in the fourth-generation 2020 Subaru WRX STI and the newest Subaru engine may get the nod. Stay tuned.

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Photo credit: Subaru Global

Comments

Big Engines (not verified)    April 30, 2018 - 1:45AM

Thanks Denis for this report

I think maybe this engine only for WRX STI but WRX may have another engine maybe smaller than 2.4-liter, is that right?

Do you think the next generation for Subaru Legacy 2020 will have the same engine from Ascent? cause they will drop 6 cylinder engine in 2020

SubaStar (not verified)    May 2, 2018 - 9:53AM

330 hp in 2020 when competitors offer 350 to 400 in 2018? Come on Subaru! Should I say: come back at the top of the niche you've created: a rally car barely legal on the road and make your loyal customers happy, the ones who forged your good, reliable and sporty image!

marc a bionda (not verified)    December 2, 2018 - 5:01PM

In reply to by SubaStar (not verified)

What competitors offer 400 hp in a 4 banger? Mercedes? 330 in a 2.4 dit would get you 400 with just a tune...The focus rs had 350 and got beat by the sti with 305hp I do believe...

Drew (not verified)    May 22, 2018 - 6:57PM

Your knocking the company who just won the Nuremberg yet again with its 2.5.
Also, competitors may be making 350-400 but they still barely run with a car that puts down 300hp because of awd and gearing. And weight... And a lot of variables other than just HP alone. 330 is still more hp than an STI at present, and not to mention with such a high compression ratio allowed with direct injection you'll get that 330hp SOONER and for a far longer period of time... and we all know time is money. No pun intended.

SubaStar (not verified)    May 23, 2018 - 5:02AM

In reply to by Drew (not verified)

Hi Drew,
Subaru and STI won their 5th SP3T-class tilte at the 2018 24H Race at Nürburgring with the EJ20 of 340 HP and not the EJ25 : it confirms Subaru is able to deliver a great output of its 2.0 mill with maximum reliability, we all know that.
I know the power is not everything in a good sport car.
I pretty share the Colin McRae's words: "Straight lines are for fast cars, corners are for fast pilots" and I really think that Subaru's philosophy has integrated that.
But no matter which 2.0, 2.4 ou 2.5 power plant to come, 330 HP in such a famous sporty road car will remain too weak in 2020/2021, despite of Subaru expertise in AWD (less in gearboxes).
In the 90's, the WRX and WRX STI were standing alone in their market segment.
It's not the case anymore, and will be even less in the future : Subaru must react and I'm pretty nosy to discover how they'll manage the hybridation on their icon.

Paul (not verified)    June 3, 2018 - 1:13PM

In reply to by SubaStar (not verified)

+1 SubaStar. I love my 2015 WRX and want to upgrade to an STI once the new gen comes out in 2020, but if Subaru neuter it with under 350 HP, I will likely be giving my $$$ to another manufacturer. The next gen Golf R, also due 2020, should come with around 400 HP and may sport hybrid tech as well. Subaru has better AWD but in a sports car, power is important too. A next gen Civic Type R may also get a nice power bump. It's a shame Ford will not offer the next gen Focus RS in North America, that will likely sport 400 plus HP as well.

Al Schneider (not verified)    August 21, 2018 - 2:39PM

In reply to by SubaStar (not verified)

These are great responses to which I hope the folks @ Subaru are taking seriously. The current edition took last place in a recent Motor Trend mag and first place was a civic type r. Come on Subaru even VW’s next R will be bigger with better awd, 400hp a (hatch) and an automatic. So subie how bout the visit concept 4 real, in a hatch, with amazing awd - an automatic - a hatch and fast - if u don’t I’ll buy a VW ....

marc a bionda (not verified)    December 2, 2018 - 5:09PM

In reply to by Al Schneider (not verified)

The next gen sti will destroy the civic type r that honda had 100 years to design...My stage 2 fa20 wrx will destroy that civic type r...VW? whole other nightmare! Over engineered unreliable garbage anymore...Trust me, I've owned plenty of them..Last real car they made was the Audi b5 s4..To suggest ditching the boxer engine? Thats blasphemy!

Brandon (not verified)    July 16, 2018 - 3:11PM

man I would love to see an inline 4-cylinder in a Subaru. they could squeeze it down a little by putting it into a w formation like Volkswagen. The boxer engine seems like they are a more complicated heavier design. it's hard to do a valve cover gasket on those and some you have to unbolt the engine mount and Jack the engine up just to get at them . And the exhaust is just a crying shame to look at from underneath. head gaskets I think have improved but are still a worrying issue to me to leak. There was a cam cover seal that was leaking on a 2011 and it dripped right onto the bank 1 O2 sensor and the engine had to be pulled to get that seal done which is ridiculous. I just think they need to go back to the drawing board on that engine. I love everything else about Subarus though.

Todd (not verified)    July 17, 2018 - 10:56AM

I’ve been a loyal die-hard Subaru guy for 10+ years until recently. I sold my high mileage 2007 WRX reluctantly, and got into a BMW M235i only because there isn’t anything exciting about the WRX or STI at this time.
I’m waiting to see what the next generation brings, but if styling isn’t more aggressive and performance numbers aren’t up there pushing the competitors I’m extremely disappointed in Subaru’s ability to keep up with incredible performance push from other manufacturers.

COME ON SUBARU!!!

Jack (not verified)    January 11, 2020 - 5:40AM

I’ve been involved with fast cars and making cars faster for nearly 60 years. I’ve heard (and at one stage used) the same old agrguments in every generation about ‘overtaking power’ and all that crap. “Blogs’ abound with the narcissistic eroticism and ‘big talk’…about how they are going to run huge HP this gear box and that and so on and on. …with not a clue about using it or the risks they run. Priodically on sees a run of some 350-800Hp ‘stage whatever’ cars being sold at huge losses. The Cosworth AWD…I own one of those also …Sapphire set the same pattern as suburu but with a different engine…get to 350Hp and goodbye transfercase….Only the 2wd (sensibly rear drive like all great mid-price range cars , not the abomination of F(romt) wd we had thrust upon us…) could handle higher Hp. Subaru has one outstanding feature..AWD. Were it F(ront) WD I wouldn’t give it the time of day.
The question is ‘who needs 350Hp or 300plus ftlbs torque. Sure you can fantasise away and create excuses yet I’m experienced enough to say probably not a person on the planet (unless racing competitively) in reality NEEDS 300+ hp….If you have it available, in sensible driving ….setting aside the lunatic fringe of ‘drifters’ and other tyre-smoking meatheads you’ll never use it, nor the torque unless towing a caravan up Mount Everest. You seek it because you want it…there’s a narcissim in there…and a need to be recognised by ‘peers’ and low-life aswell and for many, trying to use it kills you. The argument that Subaru id deficient, lagging, slacko or whatever because it isn’t meeting the same Hp (at some peak point in time) is quite immature, but woirse, destructive….Do we not want Subaru to be adventurous yet be safe, sound, reliable, tractible THE fast point-to-point but safest car to own for the working class as well as the rich? What makes a car fast point to point on the roads we have?...suspension and gearing. Thus whilst the SAAB Aero had some Hp over the SAAB Carlsson, the Carlsson was faster point to point in say mountain country. I sold my beautiful Aero and kept my Carlsson..as only 329 were built…I doubt 100 are left alive but certainly the far more profuse 2L Carlsson is dying away…the 1991 2.3 is/was ‘the’ car, much to the chagrin of Porsche and Ferrari. Today ‘quality ‘ is about looks and sound systems….read the reseller adverts.
Putting it together…press Subaru’s reseller and Fuji itsellf to get back to its Japanese roots.Get rid of the yanquis, italian…whatever…require them to respond to us, not try to lead us…or look at us as a dying breed. Ask them to bring ack the ‘pink’ gear, bring back tradition and build so that every model has at least 20 improvements of value to us and as well, introduce improvements to our early models…become a car provider to the client, not searching for some means to pull buyers away from opposition…let them buy the opposition whilst Subaru just keeps working away at maitaining a legend and an adventure…and none of that requires more than 300Hp or 300ftlbs torque.Take those figures as ‘hot enough’ and improve the rest of the car for the client…the driver. I’d take a punt and say if Subaru weakens under this Hp competition humbug it will be out of business in ten years,…and who will be to blame?...we will....we the pied-pipers.

Jack (not verified)    January 11, 2020 - 5:42AM

I’ve been involved with fast cars and making cars faster for nearly 60 years. I’ve heard (and at one stage used) the same old agrguments in every generation about ‘overtaking power’ and all that crap. “Blogs’ abound with the narcissistic eroticism and ‘big talk’…about how they are going to run huge HP this gear box and that and so on and on. …with not a clue about using it or the risks they run. Priodically on sees a run of some 350-800Hp ‘stage whatever’ cars being sold at huge losses. The Cosworth AWD…I own one of those also …Sapphire set the same pattern as suburu but with a different engine…get to 350Hp and goodbye transfercase….Only the 2wd (sensibly rear drive like all great mid-price range cars , not the abomination of F(romt) wd we had thrust upon us…) could handle higher Hp. Subaru has one outstanding feature..AWD. Were it F(ront) WD I wouldn’t give it the time of day.
The question is ‘who needs 350Hp or 300plus ftlbs torque. Sure you can fantasise away and create excuses yet I’m experienced enough to say probably not a person on the planet (unless racing competitively) in reality NEEDS 300+ hp….If you have it available, in sensible driving ….setting aside the lunatic fringe of ‘drifters’ and other tyre-smoking meatheads you’ll never use it, nor the torque unless towing a caravan up Mount Everest. You seek it because you want it…there’s a narcissim in there…and a need to be recognised by ‘peers’ and low-life aswell and for many, trying to use it kills you. The argument that Subaru id deficient, lagging, slacko or whatever because it isn’t meeting the same Hp (at some peak point in time) is quite immature, but woirse, destructive….Do we not want Subaru to be adventurous yet be safe, sound, reliable, tractible THE fast point-to-point but safest car to own for the working class as well as the rich? What makes a car fast point to point on the roads we have?...suspension and gearing. Thus whilst the SAAB Aero had some Hp over the SAAB Carlsson, the Carlsson was faster point to point in say mountain country. I sold my beautiful Aero and kept my Carlsson..as only 329 were built…I doubt 100 are left alive but certainly the far more profuse 2L Carlsson is dying away…the 1991 2.3 is/was ‘the’ car, much to the chagrin of Porsche and Ferrari. Today ‘quality ‘ is about looks and sound systems….read the reseller adverts.
Putting it together…press Subaru’s reseller and Fuji itsellf to get back to its Japanese roots.Get rid of the yanquis, italian…whatever…require them to respond to us, not try to lead us…or look at us as a dying breed. Ask them to bring ack the ‘pink’ gear, bring back tradition and build so that every model has at least 20 improvements of value to us and as well, introduce improvements to our early models…become a car provider to the client, not searching for some means to pull buyers away from opposition…let them buy the opposition whilst Subaru just keeps working away at maitaining a legend and an adventure…and none of that requires more than 300Hp or 300ftlbs torque.Take those figures as ‘hot enough’ and improve the rest of the car for the client…the driver. I’d take a punt and say if Subaru weakens under this Hp competition humbug it will be out of business in ten years,…and who will be to blame?...we will....