| The VP Story
| The 4 Basic Qualities of Fuels
| Questions
|
The four most important properties of racing gasoline... 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 VP produces different fuel for different applications. The key to getting the best racing gasoline is not neccesarily buying the fuel with the highest octane but getting the one that is best suited to your engine. Octane is the rating of 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 on the pumps at the gas stations and represents an average of the two. VP uses MON because this test method is more relevant to racing. Most other companies advertise RON because it is higher and easier to come by. Don't by 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 octane. BURNING SPEED is the speed at which a fuel releases its energy. In a high speed internal combustion engine there is very 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. ENERGY VALUE is an expression of the potential energy in the fuel. The energy value is measured in BTU's per pound, not per gallon. This difference is important as the air fuel ratio is in weight not volume. Remember, this is potential energy value of the fuel, and this difference will show up at any compression ratio or engine speed. COOLING EFFECT of the fuel is related to the heat of vaporization. The higher thhe heat 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.
| The VP Story
| The 4 Basic Qualities of Fuels
| Questions
| 
