dreamcar:
The "knock" sensor continuously monitors the combustion process and adapts all the time. If you put in 98 RON fuel after 95RON fuel the engine management system will gradually revert back to its optimum settings as the 95RON fuel "dilutes" back to 98 RON.

This has to be very precise on modern high - compression engines, the higher the compression ratio the more efficient the engine and the more subsceptible to pre ignition (knocking) by inferior fuels.

Ha, thans for answering my unasked question! I was wondering how the motor management system was measuring; put a sensor in the fuel, or by measuring the combustion process. Last makes most snese I think.

John, if you're really anal about it, you can always empty the tank with a syphon, putting the fule in a jerrycan, and fill her up with a fule of choice. That way, you won't (or at least shorter) suffer from the dilution process, alos making sure that less of the "dirt"/less quality fuel goes through the system...

 


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