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In the webinar it was mentioned that methanol/ethanol fuel are more pron to pre ignition but have a higher resistance to knock is possible for someone to elaborate on this a bit and explain why thanks in advance
Hi Adam, the main driver of pre ignition in high boost alcohol engines is a reduction in the auto ignition flash point, so that the fuel/air charge can be auto ignited at relatively low temperatures by a hot surface within the combustion chamber. The auto ignition point of alcohol based fuels is downgraded more readily than that of gasoline baed fuels, possibly due to the smaller size of the alcohol fuel molecules. To make matters worse we generally run much richer mixtures on alcohol fuels (particularly methanol) which increases the chances of the fuel wetting out against the cylinder walls and therefore the chances of oil dilution becomes greater than what we see with gasoline.