Octane Number Requirement Survey 1959-1975 Japanese Model Passenger Cars

The results of annual surveys for octane number requirements of Japanese model passenger cars during 1959-1975 showed that the octane number required to satisfy 50% and 90% in 1972 model cars increased to 91.8 and 98.5 ON, but in after that octane number requirements steadily decreased, then 1975 model cars required 89.4 and 93.5 ON at 50% and 90% car satisfaction level. About 90% of the cars tested obtained maximum octane number requirement at wide open throttle. High speed octane number requirements(80∼120km/hr) of 1975 model cars at 50% and 90% car satisfied were 85.9 and 90.2 ON.