cyrnel

Not sure I misunderstood, but to be clear, a higher octane number indicates more resistance to knocking. 87 would be more likely to allow knocking than 89. (assuming the 89 is really 89) If yours never knocks with 87 it will almost surely lose power with anything higher, unless it's detuning itself for regular.

A fair test of long term performance and efficiency is mileage. If you have a steady foot and consistent driving patterns your mileage will tell you which works better. Good luck telling the difference between 87 and 89 though without instrumentation.

Last thought would be that _very_ few cars today are built to require anything above 87. A minority automatically tune themselves depending on octane. A smaller number still require premium due to performance design characteristics (compression, timing, a braindead computer, etc.) I could be wrong but I don't think any street Hondas are in that category. Maybe NSX??

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195