Light-vehicle Horsepower Hits Historic High in 2021

The U.S. EPA data say engine horsepower is the highest ever, while average displacement remains near an all-time low.

March 1, 2022

Bill Visnic

Figures compiled by the U.S. EPA indicate average horsepower continues to increase. (U.S. EPA)

Full-electric propulsion for the U.S.’s light-vehicle market segments is gaining momentum, but developers of the internal-combustion engine aren’t throwing in the towel just yet. Figures recently compiled by the U.S. EPA to include the 2021 model year indicate average horsepower for light-vehicle engines reached a historic high of 252.2 hp in 2021.

Light-vehicle average engine displacement and horsepower by model year. (U.S. EPA)

The highest-ever horsepower figure came, said the EPA, despite average engine displacement remaining at a near-historic low. Average light-vehicle engine displacement in 2021 was 2.9L and has been less than 3.0L since 2014. The lowest-ever average displacement is 2.8L, which was recorded in several years since 2014.

Average light-vehicle horsepower hit an all-time high in 2021, despite average engine displacement near a historic low of 2.8L. (U.S. EPA)

The EPA’s light-vehicle dataset, dating to 1975, is nearing 50 years of scope. In 1975, average horsepower was 137.3 and the lowest-ever average was 102.1 hp in 1981 – despite an average displacement that year of 3.2L. Average displacement was 3.0L or larger for nearly a quarter-century from 1988 to 2013 and after 2014 has never again exceeded 3.0L. The years 1975 and 1976 had the highest average displacement, 4.8L, in the near half-century of the U.S. Dept. of Energy (DOE)/EPA’s records.

The DOE’s Vehicle Technologies Office summarized the marked increase in engine specific output by summarizing, “From 1975 to 2021, horsepower has increased by about 84% while engine displacement has decreased by 40%.” The information was derived from the EPA’s 2021 Automotive Trends Report .