The cost difference between regular gas and premium is generally about twenty cents per gallon. That means filling up a 20 gallon tank will cost $4.00 more if you fill with premium instead of regular. If you fill your car once a week the premium will cost you $208.00 more than regular over the course of a year.

Let's address the fuel economy question first. The simple answer is no, premium gas does not increase fuel economy at all.

The octane rating of gasoline is a relative number showing the amount of isooctane in the gasoline as opposed to the amount of heptane in the gasoline. To make it simple, the octane rating is a representation of how much energy it takes to ignite that gasoline. This octane measurement does not indicate the amount of energy the gasoline produces, which would be an indicator of fuel economy. The final answer is:octane rating and increased fuel economy have no relationship whatsoever!

The second question concerning premium gas making your car run better. Does it? The plain and simple answer once again is no, there is absolutely no significant difference in the performance of your car if you use premium gas.

I must add this one caveat, having said there is no performance gain, it is possible your car could show an increase of a little more horsepower with premium than with regular gas but it would be very hard for you to notice the difference. This slight possibility only allows car makers a little extra marketing advantage by using this claim on higher horsepower as part of their advertising.

Automakers can market their cars with a higher horsepower statistics by designing and optimizing their engines to take advantage of higher octane fuel anti-knock properties. Engineers generally agree that if you use regular gas in an engine designed for premium, the horsepower loss is so small, that it is almost impossible to detect.

What if your car manufacturer recommends that you use premium? In this case burning regular instead of premium won't void the warranty, nor damage the engine, most automakers say.

Next time you go to fill up try regular instead of premium. You will immediately save $4.00. See how your car performs with the regular. If it runs fine and you don't hear any knocking continue to use regular. You could save $200.00 per year!