In the world of internal combustion engines, technology has declared war on octane. Thanks to sophisticated engine control units and knock detection, ever fewer modern cars require high-octane fuel. Aircraft engines, naturally, have been left behind, stranded on their own little island of octane neediness. And so the perverse problem of finding a replacement for leaded 100-octane avgas.
But what if there’s just enough octane in the automotive gas pool to make it work in aircraft engines that had a little detonation control? That’s the idea behind Airplains’ resurrection of ADI or anti-detonation injection, a simple, proven technology that employs a light spray of methanol and water into the induction pipes to quench potential detonation, making it possible to burn lower-octane fuels in high-compression engines.