I would suggest a class/course in basic mechanical science.
Higher octane is needed because you increased the mass of the mixture prior to compression. Overall compression will be higher and exponential, not linear. Elevated octane has the property of causing the explosive mixture of gasoline to resist detonation through compression.
Let's also not forget that compressing air by any means also increases heat. There is a direct correlation between the flashpoint of the explosive mixture and the tendency to detonate from being compressed. That correlation would be indicated on a curve and would be different for every engine.
Octane ratings allow you to make an educated guess and cover a specific range of heat and compression. Those ranges were figured out ahead of time and just so happen to cover a good swath of the ranges that we operate combustion engines in. It's almost like they planned it that way
If compression stays same on boosted engines , why do they require higher octane fuel - Is it because the A/f ratio needs change when boost is added ?
I read you have static compression and effective compression on a boosted engine - effective compression goes up when boost is applied - that why higher octane is needed if you want to run boost
Higher octane is needed because you increased the mass of the mixture prior to compression. Overall compression will be higher and exponential, not linear. Elevated octane has the property of causing the explosive mixture of gasoline to resist detonation through compression.
Let's also not forget that compressing air by any means also increases heat. There is a direct correlation between the flashpoint of the explosive mixture and the tendency to detonate from being compressed. That correlation would be indicated on a curve and would be different for every engine.
Octane ratings allow you to make an educated guess and cover a specific range of heat and compression. Those ranges were figured out ahead of time and just so happen to cover a good swath of the ranges that we operate combustion engines in. It's almost like they planned it that way