yes or not worth it
Its true in a way, stock the car is "tuned" to run that gas. I believe they retard the timming to allow the cheap fuel to run ok in it.
Not to rag on you but your datalog is inaccurate to say the least.I use to think that gas was just gas but not any more. Now that i know more about it and how it works it makes sense and now i get it.
I use to get quick trip gas because i thought since it gets more buisness it would have the fresh fuel but after a few data logs ive decided im not going buy from them any more. I tried a tone of different fuels and finally found a fuel my car likes and ive been running it for a few months now.
This is what bad gas looks
And this is what the gas im using now looks like
With bad gas you rknock sensor detects knock and retards your timming. Good gas you can really wind the timming up with no knock and it improves performance.
IMO its worth the extra money. You can do your own testing but ill bet you will come to the same conclusion. You may not really feel it but you can see with the datalogging what it is actually doing.
If you read the whole paragraph its talking about the fact that in some regions regular is 85 octane and that using premium will give better performance than 85. It does not say you will get better performance than 87 octane.I use premium because it says right in the manual "premium fuel will provide improved performance" (pg. 354 (2nd printing)). Plus my station two blocks away from home has ethanol free premium.