
Putting Premium Gas in an Engine That Requires Regular? Stop It Now - hourislate
https://www.nytimes.com/2019/04/11/smarter-living/premium-gas-worth-it-octane-summer-ethanol.html
======
whenchamenia
Most new cars are now either high-compression naturally aspirated, or
turbocharged. Both of which benefit from increased octane. If you have an old,
or economy car, with lower compression, you will in fact see a bit more
horsepower and lower emissions from lower octane, as it can burn more
completely in an inefficient motor. Newer cars with knock sensors will adjust
the timing to be able to run better with better gas, many even have sensors
now (flexfuel, etc). The result is usually better power and mileage for
turbocharged engines, and slightly better mileage (maybe not enough to offset
price) in a natually aspirated one, and slightly better emissions. Be aware
USA and Europe measure octane differently.

Tldr - Buy what your gas cap says.

