FUEL of 97 + octane number gives the most miles for the dollar, present calculations show. At this point, increased efficiency from high compression ratios equals the rising cost of high-octane fuel. For town driving about 95 octane is inherently the least expensive, and over-the-road cars can benefit from gasolines up to almost 99 octane number.
This paper describes an analysis made by California Research Corp. of the costs and the value of high-octane gasolines. The economics of octane numbers was based on current commercial practices regarding improved efficiencies of higher compression ratio cars and higher manufacturing costs of higher octane gasolines. The authors believe that if compression ratio and octane number stay in proper relation to each other, the consumer will benefit.