We’ve learned a lot about the next-gen Subaru BRZ and Toyota 86. We know that a deal between both companies will make Subaru an affiliate company of Toyota and that the twins will switch over to Toyota’s TNGA platform. More recently, we learned that they would both feature a turbocharged version of the Subaru Ascent’s 2.4-liter flat-four,, and that’s a bigger deal than we thought. A new report says that the 2022 Subaru WRX STI will feature the same exact engine, although it will be tuned to deliver 400 horsepower. Does that mean that, with a little extra work, the Subaru BRZ and Toyota 86 can be pumped up to that level of performance too?

When Will the New Subaru WRX STI Launch?

Forbes’ secret sources say that the current WRX will continue to be powered by the EJ25, 2.5-liter Boxer four until the next-generation model is introduced sometime after 2021. That means that, at the very earliest, the WRX could launch as a 2022 model.

Why Will the Legendary Subaru EJ25 Be Discontinued?

The current EJ25 engine is good for some 305 horsepower in the standard WRX and has been tuned to as much as 341 horsepower and 315 pound-feet of torque in the most recent 2020 WRX STI S209. Those are admirable numbers, but the strict and ever-changing emissions regulations require some change, and the EJ25 just doesn’t hold up anymore.

That changeover comes with some major benefits outside of the improved emissions output, and that’s tunability. According to Forbes, the FA24 will be capable of producing as much as 400 horsepower. Let’s just take a minute to thank the universe that it’s happening in the WRX and not a hotter version of the Ascent, am I right?

2020 Subaru WRX STI specifications

Engine

2.5-liter flat four-cylinder “boxer”

Horsepower

305 HP @ 6,000 RPM

Torque

290 LB-FT @ 4,000 RPM

0 to 60 mph

4.6 seconds

Top Speed

160 mph

Transmission

6-speed manual

Fuel economy city/highway

17/23

Curb weight

3,391 Lbs


How Will Subaru Tune the Ascent’s Engine to 400 horsepower?

Tuning the Ascent’s FA24’s 2.4-liter engine to 400 horsepower for the WRX STI isn’t going to be all that easy. Sources indicate that Subaru is going to completely rework the engine by making a number of enhancements:

-* New, reinforced crankshaft

-* New, reinforced pistons

-* Optimized timing balance (valvetrain to crank)

-* Fine-tuned valves

-* Revised intake ports

-* Tweaked boost pressure (most likely increased somewhat significantly)

-* Improved, high-pressure fuel system

On top of this, Subaru will also up the WRX STI’s brake capacity to compensate for the huge improvement in power. After all, we’re talking about an improvement of 95 horsepower over the current STI. The Symmetrical AWD system will naturally carry over, also likely returned, and there will be a whole host of other chassis modifications, too.

Will the Engine in the Subaru BRZ and Toyota 86 Be that Same as in the Next-Gen WRX STI?

This is the big question that has yet to be answered. We know that the Subaru BRZ and Toyota 86 will employ the same engine in some respect, but most recent reports indicate that their turbocharged output will only be bumped up to 255 horsepower and 200 pound-feet of torque. However, Toyota has been adamant that the next-gen 86 will surpass the Supra in terms of driving dynamics – it’s meant to be a true driver’s car, of course – but whether or not that long list of updates taking place to make the FA24 WRX STI worthy is a mystery.

However, the revised valvetrain and intake, as well as boost tuning and timing balance, probably won’t be present when it rolls off the production line. But that’s not necessarily a bad thing. If Subaru has laid the groundwork with the pistons and crankshaft, the other modifications needed to push the BRZ or 86 into high-300-pony territory won’t be that huge.

In the world of tuning, swapping out an intake manifold and cylinder head isn’t that difficult and, if they feature the same turbo, tuning the boost and fuel delivery could be as simple as modifying the ECU. So, while it won’t be impressively easy to reach the same output as the WRX STI, one could come close without doing a lot of major work. of major work.}} A bump up to, say 320 horsepower, could potentially be done by simply swapping out the turbo and doing some computer calibration. It might not be something you can do in your backyard, but you can bet aftermarket tuners will be all over it – especially if the lower-end of the engine is already primed to handle that much power.

Final Thoughts

Right now, how the FA24 engine will differ between the BRZ\86 and the WRX STI is a big mystery, but Subaru would have to go out of its way to produce the same engine with different internals (crank and pistons,) so the reinforced lower end is actually a strong possibility. I wouldn’t hold out much hope for the improved heads or intake, though. The point is that the next-gen BRZ and 86 could be very tunable if things work out right, and that’s a pretty big deal in our book.