I’ve heard a lot of bikers proudly state, “I only use premium in my bike.”
I usually ask, “Was it knocking with regular?”
I can’t recall anybody ever telling me their motorcycle engine knocked using regular gasoline. If it doesn’t, then there is absolutely no reason to use premium except you’ve got too much money and are looking for ways to get rid of it. The only purpose of increasing the octane rating is to prevent knocking. If your engine doesn’t knock using regular, then you’re solving a problem you don’t have. Increasing the octane rating in no way helps remove deposits, prevent deposits or perform better. Premium and regular gasoline have the same energy density. Energy density refers to the power per unit. You get a bigger bang with a gallon of a high-energy density fuel than with a lower one.
Gasoline distributors put additives in their product they claim will do various things such as prevent and remove carbon deposits. The EPA actually requires a certain level of carbon removing additives. While there may be some variation in the formulation of additives between octane levels of a brand, it’s unlikely. I don’t see retailers hawking increased additives in higher grades, which means there is no financial reward for doing so. In fact, it is almost impossible for the average consumer to get the facts on additives for a particular brand. I’m not aware of any place that information is posted. In fact, Scripps Howard news service recently commissioned a lab to test 10 samples from five major brands for an article it was doing. An independent lab is just about the only way to get reliable numbers on the additives in a product. And since there is only a minimum level demanded by the EPA, those levels may change before you get the results back from the lab. There is simply no way to know, or any reason to believe, the additive package for premium gas is better than what you get with regular.
I’ve been a longtime proponent of ethanol. I’m originally from farm country and would like to live in a world where American farmers produce our energy instead of Middle East terrorists. Unfortunately, ethanol has some serious shortcomings when used with existing infrastructure. It has a shorter shelf life, it can damage certain seals and hoses in older engines. It attracts water and, finally, it has a lower energy density than gasoline. You’re mileage will not be as good with an ethanol mixture as with pure gasoline.
I’ve had other ethanol proponents tell me adding ethanol to gasoline is like increasing the octane. There is a little truth to that, but it doesn’t apply at the pump. A higher-octane rating, in simple terms, determines the combustion temperature of the gas. Adding ethanol to gasoline will increase its combustion temperature. But that is factored into the reading at the pump. You’re still getting a fuel with 87 octane. They’ve just used ethanol and less of another component such as MTBE. But because your fuel now contains ethanol, it is a less energy dense mixture. Mileage will go down. And if it sits in your tank too long, you may wind up with water in the tank.
But the seals and hoses in vehicles newer than 10 years old are safe with ethanol blends. And if you use your vehicle daily, then the ethanol won’t have time to attract a significant amount of water. And the loss of mileage, while real, is small enough that you’re likely to burn more gas looking for an ethanol-free supply than you will save with the better mileage.
My advise is fill it up with regular and go for a ride.
－ Guy Wheatley