But as M division officials have revealed to Autocar, “it is for all intents and purposes an all-new drivetrain with significant changes to the base engine that allow it to rev beyond 7000rpm and deliver a much higher specific output” than today’s S55 engine.
As well as being earmarked for the next M4 coupé and the M4 Gran Coupé, the new twin-turbocharged straight six is also planned to propel a new M4 Convertible, the upcoming sixth-generation M3 and, in a lesser-powered form, the second-generation M2. It has been launched in the new X3 M and X4 M SUVs.
An increase in power provides the new S58 engine with a higher specific output in Competition guise than the old S55 with water injection, a set-up used by the 493bhp M4 GTS.
That unit provides the outgoing M4 coupé with 425bhp in standard guise and 444bhp in Competition form.
BMW’s M division engineers have managed to raise power by more than 11% in the standard M4 and 13% in the Competition, with claimed outputs of 473bhp and 502bhp respectively.
These figures appear set to place the new model in direct competition with the 444bhp Audi RS5 and 503bhp Mercedes-Benz C63S Coupé.
Torque is also increased by 37lb ft, with the S58 engine delivering 442lb ft on a band of revs between 2600rpm and 5600rpm.