Why does ethanol produce more horsepower despite having lower energy density than gasoline?

Ethanol is less energy-dense than gasoline, yet it consistently generates more power in engines. This video breaks down the technical reasons, including air-fuel ratios, octane ratings, and the cooling properties of ethanol that allow for higher performance.

While ethanol contains less energy per unit than gasoline, its chemical composition and cooling effect provide significant performance advantages. The video examines how these factors influence power output, comparing E85 ethanol blends against E10 gasoline. It also addresses the paradox of why ethanol can be more efficient while simultaneously resulting in lower fuel economy for the driver.

The naming convention for these fuels, such as E10 or E85, refers to the percentage of ethanol by volume. By analyzing air-fuel ratios and octane numbers, the presentation clarifies how ethanol's unique properties enable engines to achieve higher horsepower, despite the inherent energy density differences between the two fuel types.

Source: Why Does Ethanol Make So Much Power? (Versus Gasoline)