is premium gas better for all cars?

You might treat your old beater like a Bugatti — pet names, meticulous hand washes with the finest of microfiber cloths, and insurance limits higher than your ride's (monetary) worth — but that doesn't necessarily mean it needs top-of-the-line fuel.

does premium gas make your car run better?

Unless your ride requires it, premium fuel won't make your car run better. And yes, there is a difference between your automaker recommending premium fuel as opposed to establishing a requirement; even vehicles that are recommended to run on premium usually don't perform noticeably different than when they're fed regular unleaded gas.

Premium fuel, with its high octane ratings, is usually reserved for high-performance and/or large engines, since "knocking" — an issue in which fuel prematurely combusts in the engine — tends to be more prevalent in high-compression engines. The damage that can result from knocking can be catastrophic over time, so it's important to take a peek at your owner's manual to see if your ride requires premium gas.

But since the vast majority of vehicles run on lower-compression engines, chances are that purchasing premium fuel is a waste of money.

The truth is, the vast majority of cars will do just fine with regular unleaded. In fact, plus- or premium-grade fuels are unlikely to affect your engine's performance or resistance to wear-and-tear in any significant way.

In other words, your beloved road warrior should run just fine on regular unleaded gas unless you drive a big ol' truck or van, an SUV, or a luxury sports car.

how is premium fuel different from regular unleaded?

When it comes to gas, "premium" refers to the higher octane levels this type of fuel contains versus regular unleaded gas. While regular unleaded is usually 87 percent octane, plus- and premium-grade fuels are more likely to contain 89 to 91 percent octane.

Higher octane ratings (which make fuel more resistant to ignition) paired with lower levels of heptane (which is significantly more likely to ignite under high compression) form the perfect cocktail for what we call premium-grade gas.

where did the premium gas myth come from?

Back in the day, engines didn't have the capability to adjust to fuels with varying octane levels, which meant using the wrong fuel could quickly lead to destructive wear-and-tear (remember that knocking we were talking about?).

But almost all post-1996 models have incorporated knock sensors into their engines, which means — instead of catastrophic failure — your car's computer will adjust itself to compensate for gasoline with too-low octane levels. This, however, will decrease gas mileage as well as peak engine power if your vehicle requires premium fuel. Your economy or mid-range ride, on the other hand, will probably see no difference in performance.

step on the gas to savings

Esurance is built to save you time, hassle, and money, which is why we're always innovating tools and technology that make your life (and your car insurance) simpler and easier. Cue our online Fuelcaster® feature, which can help predict whether gas prices at your most-visited stations will rise or fall before your next fill-up.

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