Preliminary data for model year 2021 show that the average horsepower (hp) reached 252, an increase of more than 6 hp over the 2020 model year. This is especially impressive given that the average engine displacement remains near historic lows. In the late 1970s, following an oil embargo and energy crisis, there was a dramatic shift toward engines with smaller displacement which consumed less fuel but also had lower horsepower. Traditionally, greater horsepower required larger displacement engines. As engine technologies have improved, however, manufacturers have increased the specific power of their engines, generating more horsepower from smaller displacement engines. This allows for increased performance without sacrificing fuel economy. From 1975 to 2021, horsepower has increased by about 84% while engine displacement has decreased by 40%.
Note: Data for 2021 are preliminary.
Source: U.S. Environmental Protection Agency, 2021 EPA Automotive Trends Report, EPA-420-R-21-023, November 2021.