In the United States at least there are 3 grades of unleaded gasoline at most pumps. Does it really matter what grade of gas you use? Can I use the lowest grade one week and the next week get premium if I can afford it? Does it help with milage or does it keep your engine clean? What is the difference?
In: Engineering
A lot of engines are designed differently than others. Usually “high performance” engines use a higher grade of gas (91 or higher). This is to keep the engine running at its peak performance. Let’s say you bought a classic car with a beefed up engine and the seller tells you “it runs on 91 aka “premium gas” you drive it home it feels fine engine sounds great and is full of power. Now the next day you’re on empty so you pull into the gas station and fill it up and you decide to use regular gas (87 octane). The moment you start that car you hear sounds coming from the engine. These sounds can be described as knocks or pings. This is due to the “lower octane rating” of the fuel. Regular gas (87 octane) has a lower threshold for igniting compared to premium gas (91 octane). In the car you purchased the engine is designed to run at higher pressures and higher temperatures that only premium gas (91) can withstand. When it was filled up with regular gas the pressures and temperatures of the engine was causing the regular gas (87) to ignite prematurely causing the sounds and poor performance from the engine.
For all intents and purposes this is the only difference in the fuel between premium and regular. For a car designed for regular gas, premium does not provide better gas mileage, premium does not keep your engine cleaner. Premium does not increase power. To use it thinking premium is better for your car is a waste of money.
I hope this helps clear some things up for you
Latest Answers