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This paper describes a 30 vehicle test conducted to evaluate the performance of a new gasoline additive technology. The technology consistently demonstrates an ability to control octane requirement increase of automotive engines, and even effect a reduction, under standard dynamometer stand conditions. The objective of this work was to determine if a beneficial influence, relative to unadditized base fuel, on the octane requirement of a broad fleet of typical customer vehicles could be observed. Included in this evaluation is an assessment of both octane requirement increase control (ORIC) and octane requirement reduction (ORR). Additionally, data regarding inlet valve deposits (IVD), combustion chamber deposits (CCD), emissions, and lubricant properties are included.

An electronic device was constructed which, when used with the breakerless transistorized ignition system now common on U.S. cars, allows the octane requirements of the individual cylinders of a multicylinder engine to be determined. Basically the instrument functions by retarding the spark timing of all cylinders except the one being rated. A detailed schematic diagram of the Selective Ignition Retard Device (SIRD) is included in the paper to allow construction of the unit by interested parties. SIRD has been employed in studies aimed at elucidating the factors affecting octane requirements of engines. Some typical test results are presented.