Supercharger or turbocharger? Which way will a hotter GT 86 / FR-S / BRZ go?

The Subaru BRZ and its Toyota sibling (badged Scion FR-S in North America, Toyota 86 in Japan and Toyota GT 86 elsewhere) have finally been officially launched and, in spite of its light for our era curb weight, the respectable 100 hp-per-liter power density of its FA20 2-liter naturally aspirated direct+port injection flat four and a power-to-weight ratio that betters that of the current Mazda MX-5 Miata, there is a rising clamor for more power via turbo. Never mind that such a power increase begs for larger, stickier tires, bigger brakes to slow things down and a concomitant increase in unsprung and curb weight, some people just value pin-you-to-your-seat acceleration over the finesse required to maintain momentum (i.e., don’t slow down that much when you hit a curve) in a lightweight, naturally aspirated fun-to-drive car. Yet, even GT 86 / FR-S Chief Engineer Tetsuya Tada unwittingly added fuel to the fire when, back in August he admitted to Bertel Schmitt of The Truth About Cars that the FA20 flat four shares its mounting points with Subaru’s older EJ assortment of flat fours. This would, of course, make it relatively easy to swap in, say, an EJ257, the most powerful (think North America’s WRX STI) iteration of Subaru’s 2.5-liter turbo boxer 4. Yet, perhaps, Toyota isn’t thinking turbo when it comes to a possible faster future GT 86 or FR-S…

A supercharger?!
Given all the Subaru componentry inside GT 86/FR-S/BRZ and the Pleiades-logoed carmaker’s long history of turbocharged rally-inspired go-fast sedans, coupes and wagons, it’s hardly surprising that everyone expects a turbo version as a future variant of the Toyobaru sports coupe. Yet, England’s Autocar, in an article by Andrew Frankel, reports that

Chief engineer Tetsuo (sic) Tada says that not only is a supercharged GT 86 envisaged, test cars have already been made and are being evaluated by Toyota Racing Developments (sic), the Japanese giant’s in house tuning division.

Tada-san favours the supercharger approach because it is simpler to achieve than increasing engine size and doesn’t wreck throttle response as turbocharging might. Indeed Toyota says that turbocharging along with four-wheel drive and wide tyres are what make sports cars boring to drive.

Supercharging is also a key competence for TRD which has been offering this kind of forced induction as an aftermarket kit for Toyotas since 1998. He would not be drawn on what kind of power a supercharged GT 86 might develop but Toyota is known to consider the car’s chassis could easily handle an additional 50bhp to go with the 197bhp already generated by its Subaru 2-litre flat four motor

TRD’s most popular supercharger conversion is applied to the American market Tacoma pick up, boosting its 4-litre V6 engine from 233bhp to 301bhp suggesting that a 280bhp GT 86 with, critically, a massive boost in the low down torque the car currently lacks would be easily achieved. Even in the unlikely event that all the modifications added 100kg to the weight of the car, its power to weight ratio would still at least equal that of the 326bhp Nissan 370Z, a car capable of hitting 62mph from rest in 5.3sec and recording a top speed of 155mph. The standard GT 86 needs around 6.8sec and does 143mph. It is not yet known whether, if approved, the supercharged GT 86 would be offered as an aftermarket pack or as a model in its own right.

Although this all sounds feasible and true enough, we should note the Autocar isn’t the most credible of sources, ranking just a bit above their compatriots Auto Express and the Japanese rendering mags such as Best Car in their rumormongering sensibilities. And, please note, Mr. Frankel, that Tada-san’s first name is Tetsuya, not Tetsuo. Also, the “D” in TRD stands for Development in singular, not in plural.

Toyota’s checkered history with supercharging
When looking back at Toyota’s boosted gasoline powerplants, the company’s history is akin to Audi’s, with a mix of turbocharging (Supra, 2nd-generation MR2, Toyota Celica All-Trac Turbo/GT-Four) and supercharging (1st-generation MR2, TRD aftermarket kits and Australia’s Aurion TRD). The new millennium, however, has seen nothing but superchargers. Besides the aforementioned blower for the Tacoma’s 1GR-FE 4-liter V6 (that also fits the 2007-09, single VVT-i FJ Cruiser), TRD offers superchargers for the older 1FZ-FE 4.5-liter inline 6 and 5VZ-FE 3.4-liter V6 truck engines, as well as a state-of-the-art Eaton TVS (Twin Vortices Series) blower for the 3UR-FE 5.7-liter V8 that is currently the most powerful engine offered in the Tundra and Sequoia.

The moderate, niche success of those truck applications, however, stands in stark contrast to Toyota’s luck with car superchargers. The first-ever application of the Eaton TVS blower was atop the 2GR-FE 3.5-liter V6 which, thus boosted, received the 2GR-FZE moniker. As installed in Australia’s Aurion TRD, an upmarket sports Camry V6 variant, it produced 323 hp, making it, by some accounts, the world’s most powerful front-wheel-drive car. That’s nothing to brag about, though, as prodigious torque steer, early blown engines and the worldwide economic meltdown saw Toyota shut down Aurion TRD production after selling barely 537 units in a 15-month period between August 2007 and November 2008. Similarly discontinued is Scion’s TRD supercharger for the 1st-gen tC and 2nd-gen xB’s 2AZ-FE 2.4-liter 4-cylinder engine, a victim of claims of questionable quality and reliability. And long-time 1st-gen Lexus IS and 2JZ-GE 3-liter inline 6 fans may recall rumors of a TRD supercharger for that engine that ultimately turned out to be vaporware, and current rumors of a blower for the current IS and GS’s GR-FSE V6 may well meet a similar fate.

A 2-pronged approach, with each brand going its own way on boost?
Even though the latest rumors on FT-86 pointed towards the barest of differentiation between the Toyota/Scion and Subaru variants, some were still surprised to see that the front bumper/grille unit, side vent inserts and wheels are the most overt differences between the two companies’ versions. Even the head and taillight insert variances are barely perceptible. Whether this was by deliberate design or financial cost-cutting needed to make the project happen in the first place is unclear, but we suspect that the two carmakers are banking on its success to allow for more differentiation in the future. It’s certainly difficult to envision Subaru giving in on its long history of turbocharging its boxer engines, while, if the Autocar account is true, Toyota prefers supercharging. Might this become an all-important point of distinction between the two marques?

Our thanks to the my.IS community, which inspired and informed our story via this thread.

Photo Credit: Autoblog still from a Toyota YouTube video.