3 Answers

The answer to this question is somewhat complicated, but we'll start with the easy part. The first thing you should do is check your owner's manual. It's entirely possible that the manufacturer of the car doesn't even recommend premium gas. According to USA Today, some luxury cars from Ford and GM, such as the 2009 Lincoln MKS and the Cadillac STS, have been specifically manufactured to use regular unleaded fuel. If your car happens to be one of these examples, not only will you get no advantage from using premium fuel, but it may actually be harmful to the car's engine in the long run.

Here's another helpful hint: If your car does take premium, look to see whether the manufacturer "recommends" premium fuel or if it "requires" it. If it's only a recommendation (as it will be in most cases), you can safely use regular unleaded fuel; however, you may take a small hit on performance. We'll discuss the topic of performance in a little more detail later within this article. If premium unleaded fuel is a requirement, of course, you have to pay the extra money for premium fuel every time you fill up. This is because the car's engine is precisely tuned for that grade of gas.

High-octane gas isn't necessarily better than regular grade. It isn't somehow more pure and it doesn't go through a superior refining process. It doesn't even keep your engine cleaner, as some people seem to believe. Premium fuel is just gas that contains a mixture of hydrocarbons that are slightly less combustible than those found in lower octane gas. This might seem odd, since cars use internal combustion engines that rely on the combustibility of gasoline to make them go. So, why would you pay extra money for gas that doesn't ignite quite as well as less expensive gas?

The answer has to do with the way in which expensive high-performance engines, the kind that you often find in most luxury cars, are manufactured. Find out why that matters on the next page.

6dogs, this is very accurate. Thank you my friend for the great explanation.

Premium is great stuff......if you can afford it. Unfortunately I can't, fortunately my car doesn't need it!

6dogs, I drive a Subaru and at this point of its life I don't think it would make any difference. Thanks again for your comment.