Do I Need Premium Gas?
Beyond the price at the pump, most people don’t think twice about gasoline. But when they do, they often arrive at a singular common myth about gasoline, specifically that premium gas is “better” than regular gas.
This is not the case.
Here is a quick explainer, in Q&A form:
Won’t Premium Make My Car Run Better?
No. Calling it “premium” gasoline is confusing to many drivers, who naturally assume “premium” means “superior.” In reality, the difference in octane levels in gasoline (between 87 and 93, usually) is only meant to account for different compression ratios (and therefore different ignition points) in different engine configurations. Typically, high-performance engines use higher compression to create more power, which is why most performance cars and many luxury vehicles require premium. But if your manual doesn’t say you need to run high-octane fuel, you don’t.
But Somebody Told Me It Will Help Clean The Engine
It will do no such thing.
I Drive A Luxury Vehicle; It’s Safe to Assume I Need Premium, Right?
Not necessarily. Check your owner’s manual. Or, in many cases, you won’t even need to do that. Somewhere on or near the gas cap your car likely prescribes the correct fuel for your engine. Listen to it. It was designed by really smart engineers who very much would like their work to shine.
OK, So I’ll Just By Regular All The Time Then
Not so fast. While running premium gasoline in a car designed for regular won’t damage anything but your bank account, running regular gasoline in a car designed for premium will cause the engine to “knock,” which is a mechanic’s way of saying “run bad.”
This goes back to those compression ratios mentioned above. The octane rating refers to the amount of compression a fuel can take before it combusts. If you put fuel designed for low-compression engines in a high-compression engine, you will upset the delicate timing of the engine’s firing. Your car will still run, and you may or may not notice a difference, but it will not be running at peak efficiency.
What does octane mean?
How an internal-combustion engine works.