In 1969, some Formula 1 teams discovered that running their engines with deliberately lean fuel mixtures during qualifying would produce a leaner, hotter burn that artificially elevated horsepower readings on the dyno, but then richening the mixture for race day would provide better throttle response and reliability without triggering post-race fuel inspections—a loophole so elegant that it remained completely legal because no rule specified that qualifying and race fuel maps had to be identical.
Car Fact #44 — July 30, 2026
