Is 15.1 Rich or Lean for Your Engine's Performance?
•
4 min read
For pure octane gasoline, the stoichiometric, or ideal, air-fuel ratio (AFR) is exactly 15.1:1. This means that a 15.1 AFR is not strictly rich or lean, but represents a state of perfect chemical balance for a specific fuel type. However, when applied to standard pump gasoline with additives like ethanol, this ratio behaves differently.
