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A Coordinating Research Council, Inc. (CRC) cooperative program was conducted to determine the difference in octane requirements between technical raters and “customers.” The trained raters used the CRC E-15 procedure to determine the octane requirement of the vehicles while the customers' perception and objection to knock were determined through the use of a questionnaire. The results showed that the customers' objections and perceptions were overwhelmingly based on knock, rather than acceleration performance or after-run. The difference between the technical and customer octane requirement at the midpoint satisfaction level was 3.8 (R+M)/2 octane numbers using the population comparison and 4.1 (R+M)/2 octane numbers using the distribution of delta analysis. The statistical analysis of the database also showed that the differences between customer objection and perception levels were generally small (less than or equal to 1 (R+M)/2 octane number).

A study was conducted under the auspices of the Coordinating Research Council, Inc. (CRC) to assess the potential effects of gasoline octane quality on vehicle acceleration performance. Twelve participating laboratories, representing both the oil and the automotive industries, tested a total of 182 vehicles as part of the 1989 CRC Octane Number Requirement Survey. The vehicles consisted of 78 with electronic knock control systems (knock sensors) and 104 without. All testing was performed using the 1989/1990 CRC FBRU fuel series. The results showed that acceleration performance of vehicles with knock sensors was significantly affected by gasoline octane quality.