“Simply put, unleaded fuel burns less smoothly than leaded and the toluene and benzene, which is added to the fuel to act as a lead substitute, burns to form what are called peroxides. Unfortunately peroxides are inherently unstable and explode, forming shock waves that cause detonation. This explains why engines designed to run on unleaded from the outset feature sophisticated knock sensors, which retard the ignition setting at the onset of harmful detonation.”
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