Does the gasoline octane rating really matter?

You’ve no doubt seen the octane ratings on the pumps — typically 87, 89 and 91 or 93 — when you pull up to the gas station. You might even have wondered whether you should buck up and spend extra cash, which comes back to the question of whether the octane rating matters. The simple answer is, yes, it matters. That doesn’t necessarily mean you should burn higher octane fuel, however. But before you decide, you should know what these ratings mean.

What the octane rating means – and what it doesn’t

The amount of octane in the gasoline your vehicle burns won’t significantly increase its power. It also won’t increase its fuel mileage. Nor will it make your vehicle start faster. Octane ratings simply measure the fuel’s tendency to ignite prematurely rather than burn smoothly. The higher the rating, the more it will resist it. The biggest symptom of igniting prematurely is an engine knock or ping.

Regular gasoline has an octane rating of 87; premium gas is rated 91 or 93. Lower octane gasoline is cheaper by several cents a gallon than midgrade or premium.

Cheaper doesn’t mean worse

That raises the issue of whether it’s worth paying more per tank just to run higher octane gasoline. You’ll hear different opinions on this. Some gearheads will swear that your car will perform better when you use the higher grade gasoline. But the predominant opinion is that – in rare cases – it doesn’t really matter.

Here’s when you should use higher octanes:

• If your engine knocks. This is a sign that the gasoline isn’t igniting evenly. An occasional ping won’t matter, but repeated knocks could damage your engine.
• If your manufacturer requires it. This is most common in sports cars with high-compression engines. It can also be recommended by certain luxury brands, including Acura, Lexus and Mercedes-Benz.
• If your car is older. Carbon buildup in your vehicles could affect the compression rate, which means you would need higher octane fuel.

But other than in these cases, there generally is no advantage to burning higher octane fuels, according to most experts and to the Federal Trade Commission. The vast majority of vehicles these days have computer sensors that monitor fuel combustion and adjust anytime there’s a problem.

You can go back again

If you’ve switched to a higher octane fuel because your engine is knocking, it should clear up after one or two tanks of premium. If it doesn’t, that could indicate the need to get a tune-up or other work on your car.

The good news is, once the tune-up or engine work is completed, you should be able start using cheaper gas again, with no fears that you will be damaging your engine.

Source: AutoInsurance