The Secrets Of High Octane Powered Engine Speeds

“High octane” is a term many might get a headache thinking about. And when throwing "physics" into the same sentence, one might quickly turn and run the other way. However, one need not worry in this case—here, brought to you by Greenball Tires, the physics of high octane power will be basic enough for any layman to understand.

We’ll start with the term “octane” first. Octane has to do with volatility, or, when speaking of fuel, the tendency to explode. It’s a general rule that the lower the octane number of fuel, such as 87, the easier the fuel combustion under pressure. Conversely, the higher the octane number, the harder it is for combustion. This is why high octane fuel is more expensive—high octane fuel’s trait of combustion less easily has been shown to extend the life of high-performance engines, and many of these engines require use of this higher octane fuel to function correctly.

When many people think ‘high octane fuel,’ they think ‘fuel that’s more explosive than regular fuel.’ Well, believe it or not, high octane fuel is less explosive than the fuels with lower octane levels, which is optimal for high-performance engines. The reason for this has to do with how an engine compresses gas. All car and truck engines have motors that compress fuel.

As many know, high-performance oftentimes means more horsepower. And higher horsepower means greater forces throughout the engine (where, then, more force throughout the engine means more force to the wheels, where the driver feels the resulting horsepower).

The forces we’re concerned with here have to do with the force of an engine’s pistons plunging into its cylinders. When an engine pushes a piston into a cylinder, fuel beneath it gets compressed. If the fuel has a low octane level, it combusts easier during this compression. With a high-performance engine, it is not good for fuel to easily combust as the crankshaft turns at higher-than-normal revolution per minutes. The pistons in these types of engines move so fast that if they don’t have a pocket, so to speak, of fuel that is harder to combust, the piston may hit the bottom of the cylinder, which can cause major engine problems. Keep in mind that with lower-powered engines, fuel that combusts easily is innocuous to the engine—because the pistons are cranked into the cylinder with less force, they are unable to slam against the bottom of the cylinder. So, ultimately, high octane fuel keeps a high revving engine healthy.