QUOTE(Cyphereza @ Mar 30 2016, 10:27 AM)
The higher the RON, the more efficient our engine combustion is rite? Maybe my engine already efficient enough. That's why no difference sangat...
not really. the main criteria is engine heat/compression ratio and most important of all - ignition timing.
even carb (at least for cars, not too sure on bikes, but should be similar/same) also got distributor to adjust ignition timing.
https://en.wikipedia.org/wiki/Octane_ratinghttps://en.wikipedia.org/wiki/Four-stroke_enginebasically, ignition have to occur on the TDC (top dead center)
low octane may result in pre-ignition/pre-detonation or more commonly known as knocking/pinging, which can damage the engine.
imagine the piston is traveling up on the compression stroke, a pre detonation occurs and pushes the piston down while it's supposed to go up, imagine the stress on the con rods

without using higher octane fuel, this can be solved by retarding the ignition timing (have the air fuel mixture detonated later), however the obvious downside is reduced power being produced.
if you can have even higher octane fuel, the opposite can be achieved, which is advancing the ignition timing, to produce more power as the air fuel mixture is ignited earlier so the compression's power stroke can begin sooner.
obviously, got a maximum limit on the advancement so you do not ignite the mixture before the piston reaches TDC