Lycoming and Continental Differ on 100LL Replacement

According to a story posted on Avweb, Lycoming has gone on record opposing the development of 94UL as a replacement for 100 low lead (100LL) aviation gasoline. Continental supports development of 94UL, and is currently experimenting with modifications to its engines to accommodate the lower octane level — approximately 8 octane points less than leaded fuel. Both engine manufacturers acknowledge that many of their engines will perform satisfactorily on 94UL, but the higher-power, higher-compression engines are problematic. Computerized ignition (IE2 from Lycoming; Powerlink from Continental), knock-sensing technology and in some cases, lower-compression engine overhauls are among the fixes proposed to bring older engines into line with reduced octane levels. But Lycoming warns that the drop in fuel octane cannot be made up without potentially serious impact on engine performance. Lycoming believes that 100-octane lead-free aviation fuel is an attainable goal and should be pursued.

Mark Phelps is a senior editor at AVweb. He is an instrument rated private pilot and former owner of a Grumman American AA1B and a V-tail Bonanza.

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