Fuel grades

As fuel prices continue their seemingly never-ending climb, who hasn’t wondered… Do I really need to pump Premium?

The answer is clear: and indeed, you do (but only if that’s what your owner’s manual recommends).

There’s a general misconception that higher-grade fuel is better for a car, and that makes sense on the surface. I mean: If American beer has 4% alcohol, and Canadian beer has 5% – which is better? But that’s not the way it works with fuel grades. An octane rating is not a reflection of the fuel’s power output or energy content.

Engine power is the result of fuel, spark and air coming together and exploding at the correct time in the cycle of the engine. Poorly timed explosions can create big trouble in the form of damage to the cylinder walls and piston that can ultimately lead to engine failure.

There are generally three grades of fuel available at the pumps: Regular (87 octane), Mid-grade (89-90 octane), and Premium (91-94 octane). Those numbers are a measure of the fuel’s stability — how much it can resist igniting under compression.

Higher performance engines typically operate at higher compression and so are designed to receive premium fuel. Using a lower grade can be seriously damaging to your engine and may even void the warranty. On the other hand, if your owner’s manual recommends regular grade fuel, it is designed to run well on it and it won’t benefit from the extra dollars you’ll spend to fill with premium.