Stanadyne Performance Formula protects your diesel engine and restores engine performance. The detergent and cetane improver in Performance Formula will help restore fuel economy, increase horsepower and torque. Stanadyne Performance Formula 1/2 gallon (64 ounce) jug treats 240 gallons diesel fuel. Note: All Stanadyne Diesel Fuel Additives can be blended with each other and "double-dosing" is not damaging - although it may not provide twice the benefit. Where engine and vehicle OEMs have approved Stanadyne, most of them recommend Performance Formula, which should be used year-round to ensure protection against fuel related problems.