Red Chevy Sonic! Clean Interior and Exterior.The Sonic comes standard with a 138-horsepower four-cylinder engine. An available turbocharged four-cylinder engine has the same horsepower but more torque for better acceleration. A five-speed manual transmission comes standard with the base engine, while a six-speed manual is standard with the turbocharged engine. A six-speed automatic is available for both engines. Generally, the Sonic has a smooth ride. Fuel economy ratings range from 24 mpg in the city and 34 mpg on the highway (with the 1.8-liter four-cylinder engine and automatic transmission) to 28/38 mpg city/highway (with the turbo four-cylinder engine and six-speed manual).