This behavior is likely the result of aging misconceptions about fuel quality. Decades ago, fuel quality could vary greatly from refinery to refinery, and differ even further based on fuel marketer additive blends. In 1995, the EPA introduced the Minimum Gasoline Detergent Standard, which set a specific bar for cleaning additive levels to meet certain emissions standards.

This legislation prompted extensive research to enhance additives to improve engine performance and reduce wear-and-tear. Shortly thereafter, a global committee of automakers presented an even higher choice for consumers: “Top Tier” Detergent Gasoline. The standard was widely adopted and can now be found across North America and some other parts of the world, through nearly every major oil provider.

High-octane fuels are generally assumed to have a higher energy content, which would improve power and fuel economy. But this is only true when used in engines with high compression ratios or turbochargers. While most cars today are optimized for regular gas, stricter emissions standards placed on automotive manufacturers have created a sharp rise in cars with efficient turbocharger engines. The curve is noticeable, and premium fuels will become more commonly required.

According to a 2019 study by the EPA, “in the year 2000, turbochargers were only found in cars and accounted for around 1% of the cars produced. Over time, manufacturers have added turbochargers to other segments and by 2019, 34% percent of all new light-duty vehicles produced were equipped with a turbocharger.”