- Listed below are
the four basic qualities of fuels. As in everything,
there are trade-offs. You can't make a racing fuel that has the best
of everything, but you can produce one that will give your engine the
most power. This is why we produce different fuels for different applications.
The key to getting the best racing gasoline is not necessarily buying
the fuel with the highest octane, but getting the one best suited to
your engine.
1. Octane:
- Is the rating of the fuel's
ability to resist detonation and/or preignition. Octane is rated in
Research Octane Numbers (RON), Motor Octane Numbers (MON) and Pump Octane
Numbers (R+M/2). Pump Octane Numbers are what you see on the yellow
decal at the gas stations and represents an average between RON and
MON. VP uses MON because this test method is more relevant to racing.
Most other comanies advertise RON because is is higher and easier to
come by. Don't be fooled by high RON numbers or an average. MON's are
the most important for a racing application. However, the ability of
the fuel to resist preignition is more than just a function of the octane.
-
2. Burning Speed:
- Is the speed at which a fuel
releases its energy. In a high speed internal combustion engine, there
is avery little time (real time - not crank rotation) for the fuel to
release its energy. Peak cylinder pressure should occur around 20 degrees
ATDC. If the fuel is still burning after this, it is not contributing
to peak cylinder pressure, which is what the rear wheels see.
3. Energy Value:- Is an expression of the potentialenergy
in the fuel. The energy value is measured in BTU's per pound, not per
gallon. This differnece is important as the air/fuel ratio is in weight,
not volume. Remember, this is potentialenergy value of the fuel and
this difference will show up at any compression ration or engine speed.
4. Cooling Effect:- Of the fuel is related to
the heat of vaporization. The higher the hear of vaporization, the better
its effect on cooling the intake mixture. This is of some benefit in
a 4-stroke engine, but can be a big gain in 2-stroke engines.
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