nah .. for those interested

Fuel Burn Rate

Fuel burn rate is always FIX .. of coz diff brand diff octane got differences..

but the key point is u want everything to burn at around 10-15 degree after TDC ... (if u dunno what is TDC .. then u better forget what i am trying to express)

take 1.8 engine as an example ..
1.8 engine has a 77.4mm stroke .. 1 rotation is 154.8mm

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at 3000 rpm (rotation per minute) .. per second = 3000/60 = 50 rotation per second...

one rotation is 360 degree..

1 second / 50 rotation = 0.02 second / rotation @ 20 milisecond to complete one 360 degree @ 1 rotation

20 ms / 360 degree = 56 micro second = 1 degree

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at 6000 rpm  ... per second = 6000/60 = 100 rotation per second ..

1 second / 100 rotation = 0.01 second / rotation @ 10 milisecond to complete one 360 degree

10 ms / 360 degree = 27 micro second = 1 degree

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from the 2 example above .. u can see at higher speed the time require to travel per degree is shorter at higher rpm ... but the fuel burn rate is always FIXED for the same fuel .. hence logically .. u have to advance the timing more at higher RPM so that u manage to burn everything at 10 - 15 degree after TDC ..