ron99This fuel being RON99, expected an appreciable diff in accleration from RON95! Could the knock sensor be faulty and not making the necessary nition reschedule? Reply. S.JUMP TO TOPIC. 1 Understanding Octane Ratings. 1.1 Snificance of Research Octane Number (RON) and Motor Octane Number (MON); 1.2 Impact of Octane Levels on