Better Fuel Economy is the Holy Grail that everyone wants - whether you are a driver, a boater, a professional, or anyone in between. This fact is obvious by the number of "fuel treatments" on store shelves and on the Internet, all claiming to be the biggest and best at giving these consumers what they want. More miles for their dollar.
Getting an engine to go further on the same amount of fuel can be accomplished by only two main methods - change the composition of the fuel and changing the conditions of combustion in the engine.
On the Bell Performance Blog, you can find multiple article posts about things you can do as a driver and vehicle owner to stretch your gas mileage. Here, we are going to talk on a general level about engines and fuel efficiency.
This is the area of greyness that huge but vague claims fall into. Changing the fuel composition means adding a catalyst of some kind that will change the the carbon in the fuel burns and change the heat energy that is produced. There are many kinds of catalysts but only certain kinds that are allowed to actually be used in on-road fuel - the gasoline or diesel fuel that is used by cars and trucks on the road.
What's more, no matter what kind of catalyst is being talked about, there are limits on what it can do. No catalyst can make a gallon of gasoline or diesel produce more energy than its chemical maximum. If a gallon of gas burns to make 120,000 BTUs of energy, you can't make it produce 125,000 or 140,000 BTUs simply by adding a "catalyst". Unless what you add to the fuel actually contributes to increasing that maximum energy. But then you're talking apples and oranges in comparison because you added something different to the fuel and you're not comparing exactly the same thing. But that's another show.
The second half of the equation for mileage is how well the engine "translates" the heat energy, produced when the fuel is burned, into "usable work", which in this case means mileage.
New engines do this very very well. The automotive engineers in Detroit and Japan are quite skilled at getting maximum mileage travelled out of a gallon of gas or diesel.
But it is also inevitable that as the engine accumulates miles on its life, it moves away from ideal condition, due to deposits being formed and other factors.
So the way to improve fuel economy here is to remove these deposits and get the engine back closer to new condition.