subject: What Do The Different Octanes Mean? [print this page] People often have misconceptions about fuel and how the different fuels out there work. In modern days, there are actually quite a few different types of fuel. There are the three common varieties, 87, 89, and 91 octane, but there are also diesel and E85 octane as well. What's the difference between the various kinds of fuel and are there situations in which it's good to use a higher octane fuel on a normal engine? Those are the questions we'll answer in this article.
To my shame, I've actually had firsthand experience with what happens when you put the wrong king of fuel in a motor. When I was very young I mistakenly put diesel fuel into a regular engine. After running poorly for about 45 seconds, it began to surge violently forward and then abruptly lose all power. The motor gave out completely after about a minute had passed and I had to drop $500 getting the diesel fuel pumped out of the engine and gas tank. So are there specific situations then in which it's better to use premium gas in a normal engine?
Some people are under the impression that cost equals quality, but this is not the case here. Premium gas is more expensive because it has a higher level of combustive chemicals in its mixture. It burns longer. Engines that are specifically formulated for high octane fuel have a different cycle in their engine to allow for a slightly longer burn. When you use high octane fuel in a normal engine, it will actually cause your engine to pollute more. Your engine won't burn all of the fuel and it will be pushed out of the chamber with every stroke as pollution in the air.
Some people also have the misconception that using premium fuel is good for when you're about to take a smog test. But as you can see from the above paragraph, this can actually cause your otherwise healthy vehicle to fail its smog test. So don't do it. Going the opposite direction in octane is actually the best choice. Using a very low octane, like an octane of 85 that has been formulated specially will cause your engine to burn a bit hotter, getting rid of even a higher amount of emissions than it ordinarily would, helping you to pass a smog test.
So what's E85 octane. E85 octane is a gas that is partially synthesized from ethanol. It's actually a misrepresentation of the true octane but that's a different story. What about diesel? What is that? Diesel fuel was mostly utilized in the last century. For those who have been around it, you know that diesel fuel gives off a pretty offensive odor, and for that reason, most vehicles have stopped using it, though there are still applications for some vehicles.
The other kind of fuel that can actually be combusted inside your engine is isopropyl alcohol or rubbing alcohol. Rubbing alcohol is used in certain applications, like formulas that are supposed to help you pass a smog test. It burns very hot and very clean, which, as we discussed earlier, is good for lowering your emissions. It's not safe to burn rubbing alcohol by itself however, so don't try it.
