With a history of innovation and love of performance, Sun developed and released the market’s highest octane unleaded gas, Sunoco ULTRA 93, in 1983. The company discontinued ULTRA 93 in 2005, after a solid 22-year run. With a history of innovation and love of performance, Sun developed and released the market’s highest octane unleaded gas, Sunoco ULTRA 93, in 1983. The company discontinued ULTRA 93 in 2005, after a solid 22-year run.