Everything We Know About Toyota's Rad New 4.0-Liter Twin-Turbo V-8

With its new GR GT, Toyota is getting back into the halo supercar game, in much the same way it did in 1967 with the Jag E-Type-like 2000GT and in 2010 with the Lexus LFA. Only this time, instead of naturally aspirated inline-six or V-10 engines, it's going for the supercar-standard 4.0-liter twin-turbo V-8—albeit enhanced with Toyota's hallmark hybridization. We've been warned to expect detailed information to be dribbled out over the next few months, but here's everything Toyota has admitted so far, along with what we've been able to dig up or observe from photos.

Oversquare, Not Based on G20E

BMW and Mercedes essentially team a couple of their ubiquitous 2.0-liter fours on a common crankshaft to create their V-8s, but Toyota's aluminum-block 4.0-liter won't be based on the new G20E engine family of 1.5-2.0-liter engines. Instead, it's derived from an engine developed for the canceled Lexus LC F. The 90-degree V-8's deck height is lowered by reducing the stroke from the 2.0-liter G20E's 97.6 mm to just 83.1, which balloons the bore from 80.5 to 87.5. This oversquare design portends higher revving capability and represents a strategy shared with engines like the McLaren M840T (93.0 x 73.5), while other competitors go for undersquare, including Mercedes (83.0 x 92.0) and VW Group (84.5 x 89.0). We've also been told the Toyota engine will use forged internals, including the rods, pistons, and cross-plane crankshaft.

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Power and Torque

Toyota claims its targeted total-system output for the twin-turbo V-8 engine and electric motor is 641 hp and 627 lb-ft. We expect those figures to represent a conservative estimate or a Lexus state of tune, as peak output of Toyota's four-cylinders is said to be around 400 hp and 400 lb-ft of torque in street tune and this engine has doubles the cylinders plus an electric motor.

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Hot Vee

All the cool car companies are going for the hot-vee arrangement, where exhaust exits in the valley of the vee, straight into the turbochargers, which pressurize intake air that then gets cooled and plumbed into the engine where you'd find the exhaust manifold on a Small Block Chevy V-8. The pictures indicate no orange wires leading to either turbocharger, so we're presuming these turbos are not electrified as on the Porsche Panamera Turbo E-Hybrid.

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D-4 Port- and Direct-Injection

Cutaway shots confirm use of Toyota's D-4 injection, which places injectors both inside the combustion chamber and in the intake tract, using either or both to optimize combustion under varying engine load and speed conditions. From these cutaways we can also conclude that Toyota is not utilizing its own patents for a prechamber ignition system like we've seen on the Maserati Nettuno engine and others.

Dry-Sump Lubrication

Another trick helping limbo this big honking V-8 under that slinky low hood, is dry-sump lubrication. In addition to removing the oil reservoir from beneath the engine (as well as fitting "an oil pan that has been made thinner than usual"), dry-sump lubrication allows for larger oil capacity and hence is better for high-performance track use.

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Transaxle-Mounted Hybrid Motor

To achieve a 45/55 front/rear weight balance, the eight-speed planetary automatic transmission is mounted at the rear, connected rigidly to the engine via a carbon-fiber torque tube. In place of a torque converter is a wet-clutch launch device (as many AMGs use), with the hybrid system's electric motor located just behind it, ahead of the transmission gearing. No word yet on the battery chemistry or capacity.

Keep it tuned right here and we'll share all the drip-drip-drip of information as we receive it.