I am not a professional. This my opinion. I could be wrong.
STOP!!! STOP!! STOP!! TIME OUT!
#1. Always use what the manufacture recommends.
#2. Using a higher octane does not increase performance.
#3. Using a higher octane can lower performance in some vehicles.
#4. Late model cars come with knock sensors that prevent you having to use
a higher octane due to engine knock.
#5. Unless your car is heavily modified and creates enough combustion heat using
91 and up octane is just a waist of money.
#6. Higher Octane has no extra cleaning and anti corrosion additives than any of the
Yes back in the old day's using higher octane levels helped with "Engine Knock". It still did not make any actual performance gain. Today we have computers, sensors, and actuators that work together to keep combustion temps low. Not to mention EGR valves and or Variable valve timing.
*****SAVE YOUR MONEY******