Save some fuel
If your car says it requires premium fuel, it’s most likely not lying. Many modern engines require premium because they use a higher compression ratio for better performance. This applies to almost all German vehicles and any vehicle with forced induction. Higher compression ratios mean that the intake air charge is much hotter (1st law of thermodynamics.) and therefore more prone to preignition/detonation. This is bad news as it will eventually damage the face of the engine’s pistons and any gas in the chamber is essentially wasted. Higher octane gasoline is much harder to ignite, and prevents this problem.
Some engines have what’s called a “Knock Sensor” which retards the ignition timing when it “hears” a knock. You might think this means you can use any octane level you want, but if you make the knock sensor kick in with low grade fuel, your engine will make less power and lose fuel efficiency. It’s basically a “limp home” mode to protect your engine until it gets some better fuel.
Perhaps you’ve noticed that gas is expensive! Really, really expensive*. Here are some tips on things that not-smart people might have told you to do in order to save gas, that are actually totally made up. For example, tip #3: use premium fuel. I am one of those people who fills her car up with premium gas because my owner’s manual recommends it. Some friends have agreed (like my brother-in-law) and some have disagreed and say my car doesn’t really need the premium stuff. Is my car lying to me?
* despite our complaints that gas is too expensive, the price we pay at the pump is relatively inexpensive compared to other countries, especially Europe. We’ve gotten so used to the ”cheap” prices here that when they go up, we freak out. Could our low fuel taxes and prices be from our love of mobility? The freedom to drive whatever wherever whenever? (woah tongue-twister).