Difference between Fuel Grades (Octane)

When filling up your car’s gas tank, you’re presented with different options for fuel octane grades. But what do these different grades mean, and how do they affect your car?

Let’s start with the basics: octane is a measure of a fuel’s ability to resist “knocking” or “pinging” during combustion, caused by the air/fuel mixture detonating prematurely in the engine. The higher the octane number, the more compression the fuel can withstand before detonating.

The most common octane grades you’ll see at the pump are 87 (regular), 89 (mid-grade), and 91-93 (premium).

Regular gasoline, also known as 87 octane, is the most common and least expensive option. It’s suitable for most cars on the road today, but it may not provide the best performance or fuel economy. This type of fuel is also called “Regular Unleaded” or “87 octane”

Mid-grade gasoline, also known as 89 octane, is a step up from regular gasoline. It’s designed to provide better performance and fuel economy than regular gasoline. Some cars may require this type of fuel, but most modern vehicles can run on regular gasoline without any problems.

Premium gasoline, also known as 91-93 octane, is the highest octane fuel available. It’s designed for high-performance and luxury vehicles that require higher compression ratios. These cars are engineered to run on higher octane fuel, which can provide better performance and fuel economy. Some vehicles may require premium gasoline to run properly, but for most vehicles, it’s an unnecessary expense.

E85 fuel is a great alternative to gasoline, composed of 51-85% ethanol. Benefits include improved engine performance, reduced emissions, and a cleaner burn. It’s also affordable, typically costing less than other fuel options. E85 is popular in racing as it runs cooler than gasoline. This type of fuel typically requires a custom tune.

Higher octane fuel won’t improve performance or fuel economy; it may even decrease performance and increase fuel consumption. Check your vehicle’s owner manual to know what type of fuel it requires.