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Old 09-13-2024, 01:20 AM   #18
tcoradeschi
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Join Date: Oct 2022
Location: NJ
Posts: 129
Quote:
Originally Posted by lkchris View Post
Since tetraethyl lead and MTBE are now illegal, the major octane booster added to our gasoline is ... ethanol.

I've never understood how high octane can be achieved without an additive, and most places that offer ethanol free gasoline state 87 octane or something. I'd really like to know how a high octane ethanol free gasoline can be produced these days. The real test might be in a vehicle without octane automatic adjustment.
Stop thinking about “octane” and start thinking about anti knock index (AKI) which is what you see on the pump. It’s the average of the research and motor octanes.

An overview of the materials used to increase AKI may be found at https://en.m.wikipedia.org/wiki/Antiknock_agent
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