https://www.autonews.com/article/20150428/BLOG06/304299998/the-knock-on-higher-octane
Octane is a measurement of gasoline’s resistance to ignite when compressed in an engine’s cylinder. High octane can make a small engine produce more power. For example, if you fill the tank of a 2015 Ford Mustang equipped with the turbo four-cylinder engine with 93 octane premium, the horsepower is 310. But switch to 87 octane regular and the horsepower level drops. Ford won’t say by how much, but a Ford Fusion loses 9 hp running on regular vs. premium.