Fuel Octane, Choosing The Wrong Octane Will Cost You

This is more of a clarifying post, rather than advice or tips. It’s about fuel octane, when to choose what octane for your vehicle, and what the wrong octane will do.

Why? Because I’ve heard so many people talk about how they ‘threw some high octane’ in their car ‘to get more performance’.

First the basics. What is the octane rating you see on every fuel pump everywhere?

Without getting technical and beyond the scope of this article, octane is a measure of gasoline’s anti-knocking properties. What is anti-knocking? Well, simply put knocking is a condition in which fuel burns too early in the combustion process, also called pre-detonation or pinging. It’s the instability of gasoline that causes it to burn prematurely and unstably. The higher the octane, the more stable the gasoline.

IMPORTANT: Higher octane gasoline, which is more stable, has no more energy potential than lower octane gasoline. There is no more energy to be had from high octane gasoline, then from low octane gasoline.

What octane gasoline should I be using in my car?

Use only what the owner’s manual specifies. If your car is designed to run on regular gasoline, or 87 octane. If your manual specifies higher octane fuel, such as 89, 91, or 93 use the closest octane rating available at your gas station without going below the specified rating in your manual.

What will happen if I use higher octane gas than I’m supposed to?

A few things. For one, you will be wasting a huge amount of money paying for high octane gasoline. Second, your car will not run correctly, whether you notice it or not. Higher octane fuel requires more heat and more precision to burn correctly. If your car is designed to burn 87, it will not burn 93 correctly. Third, your gas mileage will suffer. The inability of your engine to burn the higher octane gas correctly will cause your engine to produce less power and thus will require more fuel to perform at the same level.

What about using lower octane gasoline in a high octane engine?

In this situation, you will see negative effects that could be even worse. Using low octane fuel in a high octane engine will result in severely reduced performance because the engine will attempt to adjust to the lower octane gasoline. In extreme cases, or with prolonged use of low octane gasoline in these engines, pinging or pre-detonation can occur and can eventually destroy your engine. Pre-detonation causes very hot conditions in your engine and can melt sparkplug and pistons.

What fuel you use in your vehicle is important. Make sure you always follow the manufacturers recommendations. Using a fuel other than what the manufacturer specifies will in no way help you save money, gain power, or do anything other than cost you money.