Why is octane booster bad?
Because you only have to think about what octane does in the fuel to get the picture. In the internal combustion engine (2 or 4 stroke), fuel is mixed with air and COMPRESSED in the cylinder (exhaust ports closed, piston climbs). This compression causes HEAT and the heat can cause the fuel to ignite when we don't want it to (before the spark plug fires). This is called DETONATION or sometimes referred to as pinging or dieseling. To prevent premature detonation (he he he), the chemical Octane is added to the fuel to enable the mixture to compress further and allow the spark plug to ignite the fuel, not the heat from the compression (detonation). Octane is used TO PREVENT THE FUEL FROM BURNING.
Engine builders design the pistons, cylinders and heads for a specific amount of compression because the bigger the explosion, the faster the engine turns. That in turn determines how much octane is required. Let's assume your stock manufactured YZ requires 93 octane. Run not enough, say 87, and you have detonation and a short lived motor. Run too much and your fuel doesn't burn efficiently, robbing you of power and sending unburnt fuel out the exhaust. Truth is, you are better running the LOWER grade fuel if you can get away with it. However, detonation is a VERY BAD THING. It is a violent explosion within the engine that can cause grave damage. Picture this:
The motor is happily spinning along, piston rises and compresses the fuel. As the rod rolls over the top of the crank and begins its journey down and around again, there is a pop and the top of the piston is gently pushed down again, helping it along. Then on the up stroke, before the rod reaches its zenith, BANG! The heat in the cylinder has detonated the fuel/air mixture and an explosion occurs. Unfortunately, everything in the engine is pushing against that explosion at that very moment. Something has to give, usually the top of the piston, but occasionally the rod.
Look at it another way: You are pushing a child on a swing set. Back and forth, higher and higher. Right at the peak, you push again, timing it just right for the least amount of effort. But then, you get an evil grin on your face and you step closer and put your hands out and push before the swinger has made it to the top of the swing. The instant jarring, stopping and change of direction makes the child cry. You mean jerk. You made the kid cry!
My final analogy for the day. Think of gasoline (Heptane, additives, and Octane) as a Margarita (Tequila, Triple Sec, lime juice). Too much Tequila and you get fired up too early. Too much lime juice and you pee a lot.
