Mercedes crossed 50% thermal efficiency in 2018 with their F1 engine: https://www.roadandtrack.com/motorsports/a15049580/mercedes-f1-engine-efficiency/ https://

Mercedes crossed 50% thermal efficiency in 2018 with their F1 engine: https://www.roadandtrack.com/motorsports/a15049580/mercedes-f1-engine-efficiency/ https://www.roadandtrack.com/motorsports/a15049580/mercedes-... Their recent interviews suggest they are up by 2 to 3% on that Honda did too but they never marketed the explicit number.