The eagerly anticipated Toyota Supra GRMN has been spotted completing laps on the Nürburgring Nordschleife circuit. The prototype spotted features a series of high-performance upgrades which could point to more power under the hood. Key aesthetic updates to the Supra GRMN include a revamped hood featuring cooling vents, an enhanced aerodynamic front splitter, and a distinctive ‘swan neck’ rear spoiler. Upon closer inspection, one can also notice new, lighter wheels adorned with Michelin tires and an upgraded braking system.

This sharpened version of the Supra will likely benefit from significant chassis improvements and is noted to have a lower stance due to a thoroughly reworked suspension system. It will proudly bear the GRMN emblem, representing “Gazoo Racing tuned by Meisters of the Nürburgring,” indicating its enhanced performance pedigree. And that brings us to the engine under the hood. For years, it was rumored that BMW will loan their S58 3.0 liter six-cylinder.

Supra Currently Uses The B58 Engine

Currently, the GR Supra is powered by a 340 horsepower turbocharged 3.0-liter inline six-cylinder engine, known as the B58, which is shared across various BMW models, from the M340i sedan to the X7 SUV. However, there are a lot of speculations that the GRMN variant will embrace the more potent M series engine found in cars like the G87 M2, G80x M3 and M4. We asked around and, so far, no one can confirm those rumors.

If BMW M is indeed sending their S58 engine to Japan, this strategy remains a well-guarded secret. Such a decision would be intriguing, as it involves BMW supplying a high-performance engine to Toyota, a competitor yet also a partner. This move could potentially backfire, diverting sales away from BMW’s own M series products.  It’s also interesting to note that Range Rover models are powered by the “regular” BMW’s N63 4.4 liter TwinTurbo V8 engine, rather than the newer S68 M engine.

Regarding the B58 engine, it’s already established that it can exceed 380 horsepower, suggesting the possibility of this upgrade for the enhanced Supra. If Toyota does receive the S58, a Supra GRMN with over 500 horsepower would undoubtedly be an fun drive. It’s also important to acknowledge the strong partnership between BMW and Toyota, spanning fuel cell technology to the collaborative development of the Z4 and Supra models. Whether a provision for the S58 engine exists in their agreement is yet to be disclosed.