When you drive around Pasadena and the San Gabriel Valley, you’ve surely noticed the differences between prices of gasoline. If your vehicle manufacturer recommends regular grade gasoline, you may have wondered if premium gasoline will be better. Or if your vehicle manufacturer recommends premium gasoline, you may have considered filling up with regular to save a few dollars per tank. Do either of these options make any sense, or could they actually harm your vehicle?
It’s a somewhat common misconception, but premium fuel does not contain or produce more power than regular. In fact, premium gasoline actually contains a somewhat lower energy content due to additional anti-knock additives. This misconception may stem from the fact that most high-performance vehicles require premium gasoline. However, it is not the fuel that provides added power, but the tune and design of the engine. In many cases, a more highly tuned engine will increase the possibility of engine knock, and require premium fuel to prevent engine damage.
All regular grade gasolines in any given area use the same fuel, as do all premium gasolines. The only difference between brands is the mix of additives that are blended with the base fuels. These additives serve several purposes, especially the prevention of carbon deposits inside the engine. These deposits reduce performance and fuel economy, and can lead to engine issues. Since 1995, the EPA has required a minimum level of deposit control additives in gasoline. However, eight major automakers felt that the EPA standards were not high enough, and in 2004 they released “TOP TIER” gasoline standard, which provides superior deposit control by requiring more and better additives.
The key difference between regular and premium gasoline is its octane level – the ability of the fuel to prevent engine detonation or “knock”. Uncontrolled knocking can cause severe engine damage, leading to expensive repairs. Premium gasoline is usually four to six points higher than regular – in California, premium is usually 93 octane while regular is 87.
Regardless of whether your manufacturer recommends regular or premium, the best choice for ongoing performance and economy, and to preserve your engine, is a top tier gasoline. Recent AAA testing found that top tier gasolines keep internal engine components up to 19 times cleaner than gasoline that only meets the minimum EPA standards. Top tier requirements are voluntary, but 63 fuel brands have made the switch as of 2018.
If your manufacturer recommends regular gasoline, paying more for premium is a waste of money. AAA testing found no increase in power or fuel economy, or reduction in emissions, when using premium in place of regular. Likewise, if your manufacturer recommends premium gasoline, using regular gasoline may cause losses in power and fuel economy. If your manufacturer says that premium gasoline is “required”, especially if it is a high-performance car and you have high-performance driving habits, then the greater anti-knock capability of premium gas is essential to prevent knocking and provide the maximum power output. This is especially important in boosted engines (engines with turbochargers or superchargers).
If your premium fuel engine runs fine on regular and you never hear any knocking, your car is unlikely to suffer any problems. But any time you hear engine knock, you need to use a higher-octane fuel. If you’ve accidentally filled a premium vehicle with regular gasoline, auto parts stores sell octane boosters that you can add into your gas tank to make up for the difference. It is also important to read your owner’s manual – on some cars, the use of regular gasoline where premium is required can void your warranty. Why risk engine damage and loss of performance just to save a few dollars at the pump? The simple solution is just to always use what your manufacturer recommends.
If you have questions about the fuel that your vehicle needs, or suspect that your engine is knocking, come in to your Certified Auto Repair Specialist of Pasadena today. We will take care of all your fuel needs, guaranteed!
