Octane gas is available in several different grades, with each number representing the resistance to burn the fuel has; the higher the rating, the slower the burn. The most common form of octane gas is 87octane. Generally speaking, octane gas increases the cost of fuel, and the higher the grade you purchase the more money you will spend.
You can determine what type is needed for your vehicle by...
Looking at the owners manual.
Checking the manufacturerâ€™s website. Most find higher-level octane gas to be desirable because they feel that it keeps their car engines running smoother and because they feel it is a cleaner fuel. The truth though is that although it may be cleaner, most engines will notice minimal difference with the higher gas grade.