The purpose of this paper is to analyze the Reid vapour pressure (RPV) and distillation curves of four synthetic gasoline partial substituted with 2-10 % v. ethanol or 4-15 % v. ETBE. Several parameters that describe the distillation curve were investigated. These parameters specify the percentage of the gasoline that evaporates at 70°C (E70), 100°C (E100), and 150°C (E150). The Vapor Lock Index (VLI) is also calculated from the RPV and E70 parameters. Finally, the advantages and disadvantages of ethanol and ETBE, as oxy-compounds for gasoline partial substitution are highlighted.