M15

nounStandard termAutomotive

A blended motor fuel consisting of 15 percent methanol and 85 percent standard gasoline.

This alternative fuel blend is used to increase octane rating and reduce certain emissions compared to pure gasoline. Because methanol is highly corrosive to rubber and certain plastics, vehicles running this blend require specialized fuel lines and seals. It is less common than ethanol blends but sees use in specific regional markets and racing applications.

Heard on the job

We need to upgrade the fuel lines to PTFE if he plans on running M15 or higher.