New Subaru WRX STI to be the most powerful ever

The next-generation Subaru WRX STI is shaping up to be one of the most powerful models the Japanese car-maker has ever unleashed.

Sources close to Subaru have confirmed to carsales that a 2.4-litre turbo-petrol four-cylinder boxer engine will power the new WRX STI, which will be revealed in mid-2022 and available in Aussie showrooms later that year.

The all-new high-performance car will get a beefed-up version of Subaru’s 2.4-litre turbo flat four (FA24), which already bangs out a respectable 190kW/380Nm under the bonnet of the new Subaru Outback due here in February 2021.

We expect the next Subaru WRX STI’s new 2.4-litre turbo-boxer engine to get a bunch of upgraded components (pistons, crankshaft, intake ports, valves, etc) and higher turbo pressure to push maximum output to eye-watering levels – possibly close to 300kW/500Nm.

The current 2020 Subaru WRX STI is powered by a 2.5-litre turbo engine that bangs out 221kW/407Nm.

Subaru hasn’t officially confirmed anything other than the fact new WRX/STI models are coming, but our source says their engines have been signed off and we should “expect high power for the WRX STI”.

He said the new STI will be a “very exciting” vehicle for enthusiasts and that its new engine will continue to offer plenty of scope for tuning.

Together with what’s expected to be a tweakable version of Subaru’s symmetrical all-wheel drive system, the new WRX STI will be a welcome return to high-performance machinery for the Japanese car brand, the only recent product releases from which were hybrid versions of the XV and Forester SUVs.

It’s not yet known how closely the new WRX and STI models will resemble the Impreza vehicles with which they previously shared their DNA, but the hard-core aero package you see here on our latest STI render is reflective of what could be needed to make a circa-300kW all-paw monster stable at high speeds.

Meantime, the fifth-generation Subaru WRX will make its global debut around April 2021, before cars arrive on Australian soil later next year.

While speculation is rife the new Subaru WRX will also get a version of the 2.4-litre FA24 turbo boxer, our source wouldn’t be drawn on whether the 2.4 was locked in for the WRX.

The current Subaru WRX’s 2.0-litre turbo-boxer produces 197kW/350Nm and both those numbers would have to increase for its successor to remain competitive with the Ford Focus ST (206kW/420Nm), Hyundai i30 N (202kW/378Nm) and perhaps the upcoming Toyota Corolla GR.

The next WRX has also been rumoured to get the circa-220kW 1.8-litre turbo engine that debuted in the concept version of the next Subaru Levorg earlier this year. However, it’s understood that vehicle’s powertrain and release date are yet to be locked in.

Which gives rise to another possibility – an even more downsized, 1.6-litre turbo-petrol boxer four.

World Rally Championship involvement worked incredibly effectively for the Subaru brand in decades past and while the WRX may be too large for the current rules, it could be powered by a smaller, Euro-friendly 1.6-litre turbo four that may also be seen in another rally-capable Subaru vehicle in future.

Toyota kingpin Akio Toyoda has reportedly been pushing Subaru to rejoin the WRC and while the 2020 season has been postponed, late 2021 will see the WRC return to Japan for the first time in over a decade.

According to our source, the chances of a hybrid powertrain being available from the launch of either the WRX or WRX STI are slim.

But it’s possible that a mid-life update around mid-decade could bring an e-BOXER hybrid power boost while reducing emissions.

As it stands, it’s not known what transmissions will be offered with the next Subaru WRX and STI models.

Subaru execs have previously stated that a manual gearbox option is almost a certainty for the fifth-generation WRX/STI. However, the current (or even a new) CVT automatic transmission may not be able to withstand the WRX STI’s higher outputs.

Powertrains will be crucial to the success of the new Subaru WRX and STI, but designs will also play a pivotal role in whether customers get on board.

The Subaru WRX has polarised opinion throughout its four generations and the Mk5 model will again be scrutinised by all and sundry.

“We get to see the cars in clay and have our input in terms of design language, performance or output,” Subaru Australia managing director Colin Christie previously told carsales.

“But that doesn’t mean you get exactly what you want.”