There are usually 3 types of gasoline: regular (87 press), mid-grade (89 press), and premium (91 or 93 press). If you put two high of an octane (89+) in your vehicle, you’re simply wasting money. Gasoline companies often try to argue the additives in mid-grade and premium gas is better for your car. In reality, all gas contains detergents to keep a fuel system clean. Healthy engines that take regular gas do not benefit from higher octane gas. If you chose too low of an octane for your vehicle (such as 87 instead of 91), your vehicle will get lower gas mileage and your engine will produce less power. It’s possible your engine will be damaged, but this is unlikely.
What’s the point of having different octane ratings anyway?
Octane ratings indicate the gasoline’s resistance to pre-ignition. According to merriam-webster.com, it is ignition in an internal combustion engine while the inlet valve is open, or before compression is completed. Aaron Gold from cars.about.com in “What kind of gasoline should you put in your car?” wrote:
Here’s the deal with pre-ignition: Engines work by compressing a mixture of fuel and air and igniting it with a spark. One way to get more power out of an engine is to increase the compression of the fuel-air mixture before burning it, but these higher compression ratios can cause the fuel to ignite prematurely — that’s pre-ignition, also known as knock (it makes a soft knocking sound, not unlike the gurgling of a coffeemaker). Higher octane gasoline is more resistant to pre-ignition, which is why high-compression engines (often found in luxury or sports cars) require premium gasoline. Decades ago, pre-ignition could cause serious (and expensive) internal engine damage. Modern engines have knock sensors that detect pre-ignition and recalibrate the engine on the fly to avoid it. Pre-ignition is still bad for your engine, but it’s less likely to occur.
What should you do?
Check out your car’s owner manual if you’re unsure of what gasoline to put in your vehicle. If premium gas is required, use it. If premium gas is recommended, still use it for better performance. Like we stated before, if your car takes regular gas, don’t use a higher octane rated gas because it’s a waste of money.
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