Quote:
Originally Posted by dyim
And I thought modern ECU can adjust ignition timing to compensate for lower octane so that there will be no knocking?
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They do (up to a point), but they adjust based on the knock sensor, hearing(before the driver) knock. But I fail to understand the reason the sensors should be hearing knock at idle? So why should fuel "octane" to be affecting idle? Maybe another characteristic, other than "octane"? Petroleum fuels and lubricants are complex products with characteristics beyond those that we use to label differences(eg. octane), that are often not appreciated.
Also we have to remember that a vehicle is a system, so are vehicles designed to operate with available fuels, or are fuels designed to operate with available vehicles. The answer should be both!
The suggestion reported in the original note should be taken with a grain of salt until all the facts and evaluations are revealed.