Re: Unleaded gas

Posted by Owen_Dyneto On 2018/4/2 13:50:05

Chuck, there were very definitely engines that needed TEL for antiknock in the prewar era, remember that octane ratings of many fuels in the 20s was perhaps 50, sometimes less. It was the introduction of TEL into these very low octane fuels of the time that enabled engine manufacturers to begin increasing compression ratios. Said another way, the obstacle faced by motor manufacturers to increasing compression ratios was the lack of fuel with sufficient anti-knock characteristics. TEL as an antiknock additive was discovered about 1920 IIRC and fuels with it were commonplace shortly thereafter. As combustion pressures and temperatures increased, TEL also played a role in prolonging valve seat and face surfaces by inhibiting "microwelds". There are several good histories that cover the interplay between engine development and fuels.