Many drivers still remember pulling up to the fuel pump and having to choose between leaded and unleaded gasoline. Vehicles built between the 1920s and 1970s ran on leaded fuel which helped protect a car’s soft valve seals. Unfortunately, what was good for a car was not healthy for the environment or driver. The leaded gasoline fumes spewing from the exhausts of millions of cars were deemed unsafe and, as a result, leaded gas was eventually phased out.
When you pull in to fill up your tank, three large numbers display your choices: usually 87, 89 and 92. What do they mean? Octane ratings actually range from 87 (regular) to 94 (premium). The rating is the measure of a fuel’s ability to combat pinging or knocking during the combustion stage when the air and fuel mixture can prematurely detonate in the engine.
Depending on the vehicle you drive, these octane ratings (or grades) matter. High-performance engines do benefit from a higher-octane fuel. How? These engines are designed to generate higher compression within the cylinder, but if they don’t get the fuel they need, the result is decreased performance and power.
Selecting the Right Octane Fuel
Determining which octane rating your vehicle needs can be as simple as looking in the owner’s manual. Some people like to experiment with different octanes to see if they notice a difference.
If your vehicle runs great on regular gas and there’s no knocking, pinging or other performance issues, you can save yourself some money at the pump. Just be sure to confirm that using a lower-grade fuel doesn’t affect your warranty or run afoul of specific manufacturer guidelines.
Those guidelines are there for a reason. Using a lower octane fuel can cause your vehicle’s engine to run poorly and, in a worst-case scenario, can damage the engine and emissions control system. While many newer vehicles can adjust the spark timing to reduce knocking, it doesn’t mean engine power and fuel economy won’t suffer.
The Bottom Line on Octane Ratings
You may have heard that gas companies are just “ripping you off” by charging more for higher octane fuels. The truth is that these fuels do cost more to produce. The question is whether you’re your vehicle actually requires a higher octane to perform better. In many cases, the answer is no. That’s when using a higher octane becomes a personal choice.
Some people say they notice a difference in their vehicle’s performance, and others like how higher-octane fuels reduce carbon dioxide emissions when hauling heavier loads or towing a trailer. But for most, and unless your vehicle requires it, under normal driving conditions you’ll probably get little to no benefit by choosing a higher-octane fuel.