As gas prices have steadily climbed in the United States in recent years, many excuses have been made. One of the reasons frequently given by politicians who tend to legislate in ways favorable to the interests of large oil companies has been specialized fuel mixtures that attempt to minimize evaporative losses of fuel and adjust the oxygen content to optimize combustion. Over the years oil companies have added stuff like MTBE and ethanol as part of these efforts. Another thing that most people don't realize is that there is no such thing as "pure gasoline." The fuel known as gasoline is not any one chemical. It is a blend of several different petro-chemicals, primarily heptane, and octane, which are base hydro-carbon compounds with carbon chains consisting of 7 and 8 carbon atoms respectively. Depending on the desired octane rating of the fuel they combine these and many other chemicals in various proportions. One of the best known additives in the past was tetra-ethyl lead. This "lead" was used as a cheap way of raising the effective octane rating of the fuel. It was F1 racers, though, who took fuel formulation to the next level.
More after the jump[Source: F1 Racing Live]
American gas pumps are not the only place to find multiple fuel formulations. The world of Formula 1 racing has long been a place where oil companies devote a lot of resources. Besides developing low lubricants that withstand extreme temperatures and pressures while minimizing friction to allow engines to spin up to almost 20,000 rpm, they put a lot of effort into developing fuels. F1 rules have long required the cars to run on gasoline with a maximum octane rating of 102. Prior to 1993 they were largely free to run almost anything as long as the octane limit was met. They tried all kinds to get the maximum amount of energy from the minimum amount of fuel. Contrary to what you might think fuel efficiency can actual be a benefit to performance. In F1 they set a minimum weight for the car without fluids. Carrying more fuel in the race adds weight. Weight is the enemy of performance. If the cars can get away with carrying less fuel and still run the distance they have an advantage. During the 1980s, F1 rules also set a maximum fuel capacity for the cars. To get the maximum energy, from a given volume of fuel, engine makers and fuel suppliers tried all kinds of things. Honda in combination with Shell at one time during the 1.5L turbo era went so far as to power their engines on a mixture of almost pure toluene, a known carcinogen. They even published an SAE technical paper about this fuel, which I think I still have a copy of somewhere.
In those days the crew members that were handling the fuel had to where fire-proof hazardous material suits, with full ventilators to ensure that they didn't inhale any of the fumes. In 1993 the rule-makers had a crackdown when they declared that all the fuels had to conform to European Union health and safety regulations. The stated intention of the rule-makers at the FIA was that the cars should be running on "pump gas." Of course since this can't actually defined, this turned out to be a mere speed bump for the chemists and engineers. Compounds like toluene and benzene were outlawed, but the pace of development didn't slow down a bit. The oil companies are constantly tweaking their fuel formulations in formula to optimize performance while meeting the rules. They are also adjusting formulas at the pumps where we get our fuel to meet the requirements of rule-makers in government. Pumps in every region of the country and during every season have different formulations to try and meet the rules.
Today, F1 engineers continue to try to get the most power from the lightest car (and fuel) and their efforts are green indeed.