This paper describes an experiment designed to evaluate the road antiknock performance of low-lead and nonleaded gasolines.
Over 100 test fuels covering a wide range of Research octane number, lead content, sensitivity, and front-end quality were prepared. They were then tested in nine European and one American car under both accelerating and wide-open-throttle constant-speed conditions. The design of the experiment and the analysis and interpretation of the results are described.
It is concluded that, in general, in European cars knocking at low speed road antiknock performance can be adequately described in terms of Research octane number, sensitivity, and front-end quality and that there is no additional benefit to be gained from the use of a high concentration of lead. By contrast, in European cars knocking at high speed and in the one American car tested, gasolines with a high lead content gave a better performance than the equivalent nonleaded gasolines. This was particularly so in the case of fuels leaded with tetramethyl lead as opposed to tetraethyl lead.