Using Ethanol to raise octane levels is what confuses me.
Shell puts no Ethanol in its premium high-octane gas.
Wouldn't it make more sense to do it the other way around?
Modern engine computers will make the most out of whatever they are fed, but there is only so much energy in a gallon of gas, and if it is cut with Ethanol the performance will suffer no matter what. Non-E premium must get significantly better performance.
My poor old '70s engine will hurt.