Ask the Editors: Does Premium Gas Keep Internals Cleaner?
I have heard on more than one occasion that it is good to run premium in small engines for this very reason. But now I actually have evidence that MAY support this claim. Any thoughts?
~nachop
Good question! We dug around and talked to various fuel suppliers/ brand representatives and here’s what we discovered. The Environmental Protection Agency requires that all gasoline sold in the United States include some detergents mixed in before being sold at the pump.
Generally speaking it is common practice for premium gasoline to contain slightly more detergent than regular unleaded gasoline, BUT and this is an important but, hence the caps: It is not mandatory nor is a constant from state to state or even from one brand to the next. What this means is the good results you have had with your own experiments may well be the result of the specific brand you purchased and the station where you bought it. It’s also entirely possible that purchasing regular or mid-grade fuel of that same brand from the same station could yield similar results in removing deposits.
The reason the science is rather inconclusive on this subject is simply because of the fact that, unlike years past, the EPA demands that all unleaded gasoline sold, regardless of octane rating (grade), detergents must be included designed to keep engines clean. The potency and effectiveness of said cleaning agents is dependent upon the distributors in question.
The conclusion we came to after doing research on the subject is that if you purchase premium gasoline strictly for its engine cleaning properties, it would likely be more economical and just as effective to fill your gas can up with regular and to pick up a bottle of detergent additive at an auto-supply store.
