Hmm…. The higher the octane rating, the SLOWER it combusts. They used to add tetraethyl lead to petrol to increase the octane rating, slow down the ‘bang’ and therefore reduce ‘knocking’, ‘pinking’, or detonation, enabling higher compression ratios to be used, and thus more power. Years ago Lofty Avis wrote about running his Scott on paraffin when there was fuel rationing. He had to start up on petrol, then ease over to paraffin when the engine was thoroughly warmed up, just like the old farm tractors. He said that there seemed to be more torque and tractability, (no pun intended !), at lower revs, but less top end power.