Quote:
Originally Posted by phoenix1963
[ BTW: the conditions for detonation of the fuel-air mixture are not really to do with a particular temperature. Detonation happens because the sound-speed is higher on the high-pressure portion of a pressure pulse, so the pulse gradually sharpens-up until it becomes discontinuous - a detonation. So I'm afraid the run-length of the pressure pulse (i.e. the geometry of the cylinder) is a big factor. ]
56RAF_phoenix
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Great point. But in the case of changing the fuel of an engine without modifying the design, the geo of the cylinder is fixed. Tht's why I am talking about T=f(octane grade) that is becoming the prime factor for the E you can output from the fuel (I might have the formula somewhere... In Canada, damn !).
My answer was to this :
Quote:
Originally Posted by CaptainDoggles
If you're talking about switching from 87 up to 100 octane, you need to go look at what the definition of an Octane number is. Octane number does not mean the fuel has more energy in it.
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If you change the fuel, the minimum you wld need is to modify the compression volume and material of the pistons/cylinders that you have an equivalent heat flux. Today, tuner can play with the injection para to artificially reset the volume or modify the air compression ratio playing with the boost ratio (carburated and injected) .
But this imply modifying extensively the engine. Especially if your daily hobby is a long and lonely flight in a single engine plane above the sea!
07-14-2012, 07:01 PM
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