When it comes to the day to day operation of your vehicle, few things are more important than having the proper octane level in your unleaded gasoline, especially when it comes to modified vehicles. While fuel costs often times seem to have a heavier weight than octane rating for the average consumer, this stems from the common misunderstandings about the nature of octane itself. When choosing the proper fuel for your vehicle, consider using the following tips to help you decide.1. Understand Octane’s Role in your Fuel
The first step to properly selecting the right octane level for your vehicle is to fully understand what exactly an octane rating is. When fuel is injected into your engine, it is mixed with air and compressed, before it is ignited via the spark plug. When an engine compresses this mixture of air and fuel, it must remain stable until the spark plug triggers it, or else the energy released during combustion will cause damage to the engine rather than working in synergy with it. Octane rating simply, is a measurement of a fuel’s resistance against detonation, or early self ignition due to pressure or heat. It is not a measurement of power potential of a fuel.2. Check your Owner’s Manual
When deciding on which octane rating to use in your vehicle, your first step should be your owner’s manual. Your manual should list the minimum octane rating the engine is compatible with, and any fuel used should be of the listed rating or higher. 3. Decide on Performance
Using a higher octane fuel than recommended will not always make a difference, especially in older vehicles. In newer vehicles however, especially turbocharged or high compression performance vehicles, the higher the octane rating, the better. In these modern engines, equipped with variable timing and knock sensors, the use of a higher octane fuel may allow advanced ignition timing and more performance-oriented engine settings. This in turn, can improve throttle response and available power. Using a lower octane fuel may not immediately damage your engine, but it may leave your vehicle feeling sluggish and lacking in power, especially in overly hot weather. For vehicles with modified engines, using the highest octane fuel available along with an octane booster may be mandatory rather than optional in order to prevent damage and maintain high performance. When in doubt, using a 91 octane is a safe bet.For older vehicles without computer controlled timing or variable valve timing, there may be little to no point in using a higher than recommended octane fuel with stock timing settings. Using the lowest octane your vehicle can support, will only save you money in such cases. In vehicles that are modified, or in vehicles with computer controlled ignition and variable valve timing, the use of the highest octane fuel available compared to the minimum recommended rating may mean a difference of as much as 5-10 horsepower or more. For modern, stock engines then, their flexibility allows you to use the minimum octane rating for commuting, and a higher octane for weekend cruises and performance driving. This gives you the best all around compromise between cost and performance.