Regular vs. premium? What is plus gasoline? What is octane? What is top-tier gasoline? Does paying more for gas help my engine/car perform better?
Drivers confront these questions every time they go to the pump. Picking the right gasoline can be complicated. It requires a driver to meet manufacturer requirements and balance short- and long-term financial, environmental, and performance objectives. We make it simple and easy for you to choose what’s best for you and your car.
Having swiped your credit card or paid the attendant at the station for your fuel, you now have to make a decision – do you go with regular, plus, or premium gasoline? What is recommended by your manufacturer? What is required? How do you know?
Many of us grew up believing that “premium” gas is better because it is cleaner. But what actually makes premium gas “premium”? Does it make sense to use it if isn’t required?
To make things more complicated, so-called “Top-Tier” gasoline has gained popularity in the past decade. How is this different than premium gas? Does it make sense to use if it isn’t required?
To help you make better decisions at the pump, we break all of this down for you in this Post. The short answers:
- Use whatever minimum octane rating is required for your car. Using a lower rating could damage your engine. Unsure what is required? Check your owner’s manual.
- If higher octane gas is not recommended for your car, then do not buy it. You are paying extra and not getting anything in return.
- If higher octane gas is recommended for your car, it could make sense to buy it under certain circumstances, but you will spend extra on gas:
- If you want to drive more sustainably by reducing your emissions through improved engine performance and fuel economy;
- You are going to be hauling extra weight or towing and would benefit from improved engine performance; or
- Before emissions testing.
- With a modest price differential, paying extra for Top-Tier gas can provide long-term economic benefits by reducing engine wear and tear.
Gasoline Grades and Top-Tier
What do gasoline grades mean? The grades refer to the amount of octane present in the fuel. Typical regular fuel contains an octane rating of 87 (85 if you live in mountainous/higher elevation climates), plus/midgrade is rated at 88-90 and premium at 91-94. The actual quality and energy content of the fuel is the same regardless of the grades of the gas. We will explain the purpose of octane below.
Top-Tier gasoline is not the same as premium gasoline. Top-Tier gasoline means that the refinery went above the minimum standards for detergents added to gasoline to better protect the engine and its components. It is brand-specific. Top-Tier gasoline comes in all grades – regular, plus and premium and a study conducted by AAA indicates that it is in fact worth the extra cost.
What Does Octane Do?
Certain vehicles require the use of plus or premium gasoline with higher octane ratings because those engines were engineered to have a higher compression ratio or turbo/supercharging, which forces more air into the cylinder for combustion. These vehicles require higher octane gas because octane has the ability to resist knocking or pinging caused by premature detonation of fuel. Therefore, using regular gas on a vehicle that requires premium can cause significant damage to the engine.
However, a vehicle that calls for regular gas will not benefit from premium gas because that particular engine does not have the compression ratio necessary to take advantage of the higher octane levels in premium gas. Fewer drivers require plus or premium fuel as only 10% of drivers in the US own a vehicle that recommends plus gas while 16% of drivers in the US own a vehicle that recommends premium gas.
Required vs. Recommended
Required means exactly what you think it means: You must use a fuel with the required octane rating to avoid damaging your engine.
Many vehicle manufacturers are now utilizing higher compression engines to improve fuel economy in light of the standards set by the government. These vehicles do not require premium but recommend it as it can achieve higher fuel economy and power. The Automotive Research Center at AAA conducted a study to better understand the benefits premium fuel provide to a vehicle that recommends it and found that on average, fuel economy improved by 2.7% while horsepower increased by 1.4%. The gains are minimal (and you will not save money on gas because the price differential between plus and premium is almost always greater than 2.7% — the spread is currently 8% across the US). But if you are driving in extreme situations where improved performance is necessary, such as heavy towing and cargo hauling, the benefits could be worth the extra cost of premium gas.
If you care more about reducing emissions than the price you pay at the pump, then using premium when it is recommended can be a way of driving more sustainably. In addition, we would recommend using premium for emissions testing – vehicles that recommend premium have computers that optimize for premium fuel, therefore, to maximize the likelihood of passing emissions testing, pump with premium before you take it in.
Everyone needs to know the required octane rating for the gas they put in their car. They should not use gas below that rating.
If your car calls for regular gas, pumping premium is likely a waste of money as it will provide no benefit. If your car recommends premium, we would recommend using regular unless you are willing to pay a bit more to drive more sustainably or are going to be driving in demanding conditions where a bit of extra performance could make a difference in safety and comfort.
Top-Tier gasoline comes in all grades (regular to premium) and is worth the extra cost due to its abilities to make engine cleaner and more efficient. However, it is important to note this – Top-Tier does not equate to premium as you can have Top-Tier regular as well as Top-Tier plus. Top-Tier is based on the brand, not the octane rating.
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