Octane Number Requirement Survey of 1973 - 1981 Japanese Model Passenger Cars

We described the results of annual surveys for Octane Number requirement of Japanese model passenger cars during 1973-1981.

In this period Octane Number requirements showed gradual decrease in both of the 50% and 90% car satisfaction levels up to 1978 model cars at 89.3 and 93.5 ON, but thereafter increased to 90.2 and 94.7 ON in 1981.

High speed Octane Number requirements usually showed 3-4 ON less than the low speed Octane Number requirement, however, but in recent years the difference is getting smaller.