Leaked: Toyota Supra will get 250kW, auto-only

UPDATE 13/02/2018: Just hours after this story was published, Toyota issued a short press release all but confirming the born-again Supra will make its world debut at the Geneva motor show on March 6. Here's the statement:

"The Legend Returns.

"At the 2018 Geneva Motor Show, the unveiling of a modern racing concept will signal Toyota's commitment to bring back to the market its most iconic sports car.

"Toyota's press conference is on March 6 at 9:45am in Geneva (7:45pm AEDT)."

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Top-secret technical specifications of the all-new Toyota Supra have reportedly been leaked online, claiming the new halo coupe will come with a 250kW/450Nm turbocharged 3.0-litre straight six-cylinder engine.

Controversially, according to Japan's Best Car magazine (whose pages were published by a Volkswagen enthusiasts site VW Vortex), a manual transmission will not be an option.

Instead, the Supra will come with an eight-speed automatic.

Claimed to measure in at 4380mm long, 1855mm wide and 1290mm tall, Best Car says the Supra will be 1mm longer, 54mm wider and 5mm lower than a Porsche 718 Cayman.

With a kerb weight of 1496kg, the Supra will be around 36kg heavier than a Cayman S with Porsche's PDK dual-clutch transmission fitted but could still come close to matching its German rival's 4.2-second dash to 100km/h.

That's because the Toyota's 3.0-litre turbo six is set to have an overboost function that adds an added 50Nm to the Supra's already superior 450Nm torque peak (v 420Nm).

The eight-speed auto is also expected to feature a launch control feature.

Since it's been co-developed with BMW it's likely the 3.0-litre turbo engine is the same B58 six-cylinder lump that's used in a range of BMW models -- most likely including the new Z4 on which the new Supra is based.

As well as the 3.0-litre, in some markets a smaller, less powerful 147kW/185kW version of a turbocharged 2.0-litre four-cylinder will also be offered, but it's not known if that car will also only come with the eight-speed auto.

Unusually, the Japanese magazine also suggests the Supra would ride on small 17-inch rims but it's almost guaranteed larger 18- and 19-inch rims will also be offered.

Sadly, none of Best Car's claims have been verified

Enthusiasts still hope we'll see the Toyota Supra launched at this March's Geneva motor show but, again, nothing has been confirmed by the Japanese car-maker.

Internally codenamed the J29, the Supra has been caught numerous times by spy photographers around the globe testing ahead of its global launch.

Sharing an all-new platform with the BMW's forthcoming Z4, the new Supra is expected to benefit from the German car-maker's investment in carbon-fibre, with the Toyota coupe benefitting from a structure that's both lightweight and rigid.

Inside, rumour has it the Toyota will also feature switchgear, an infotainment system and even a gearshift lever lifted directly from existing BMWs.

Originally it thought an advanced all-wheel drive hybrid powertrain would also star but the Japanese mag made no mention of it, so it's not known if those plans have been scrapped to keep development costs as low as possible.

Either way, expect Supra pricing to start north of the compact 86 coupe, which is currently priced between $30,790 and $38,790.