What we can tell you is that, of course, this type of engines don't use the gasoline or diesel one can purchase at any gas station around the world, but the fuel they do use is not so different from that. Of course each series has to obey certain rules regarding the type of fuel used, but the ones that go with gasoline/diesel don't usually allow the teams to add anything more to it.
Fuel manufacturers are allowed, however, to work with the components of the gasoline (for example) in order to affect the chemical reaction inside the combustion chamber and therefore improve the power rating of the engine.
In some championships, however, the rule makers have decided to pursue more environment-friendly solutions, as switching to greener fuels (mainly second generation bio-fuels) seems to be a strategy picked up by most series worldwide.
So the next question in mind is how come the engines boast such a huge amount of power and be as reliable through an F1 season as they are with regular, day by day fuel that you can buy at any gas station? The answer is quite simple: the fuel companies that work with the F1 teams (and who are supplying them with the necessary fuel and lubricants free of charge, by the way) are preparing the gasoline differently, mixing its composition in a way in which it offers more "violence" in the burning chamber.
As all of you probably know by now, the gasoline gets mixed with air in the cylinder to generate combustion. The F1-prepared gasoline therefore has to contain more explosive particles in order to generate more power and also secure a better fuel economy. So the simple thing the aforementioned companies have to do is do the math right and produce the most effective mix of saturated and non-saturated components in order to achieve that high degree of explosiveness.
As compared to the unleaded fuel petrol used by your regular road car, the gasoline used by the F1 machineries has only one thing in common: the proportion of paraffin. While paraffin is found equally distributed in both road car and F1 gasoline, the components that change proportion dramatically are the non-saturated ones. And that's because the molecules have a lower amount of hydrogen atoms to saturate the carbon atoms, therefore increasing the octane rating of the gasoline.
As compared to the fuel used in road cars, the amount of non-saturated components (such as aromatics, diolefins or acetylene) is much higher but cannot exceed the limit imposed by the FIA. For example, the aromatics (such as benzene, toluene and the xylenes) are better proportionate inside the F1 gasoline (15 percent, as compared to 10 percent in road cars). Overall, there are 45 percent non-saturated components in an F1 fuel, as compared to only 20 percent in the one used by road cars.
Aside from the octane count, the FIA also controls the density of the oxygen and nitrogen mix.
We're pretty sure most of you know what ethanol is, but just in case, we'll keep it for the record that ethanol should not be confused with the term bio-ethanol. While the latter is extracted from agricultural feedstocks, the former is also known as ethyl alcohol and has the same texture as the alcohol found in alcoholic beverages.
The reason why the North American body have chosen this type of fuel is, on the one hand, because it's a renewable fuel, and on the other hand, because it's one of the most environmentally friendly types of fuel in the world.
“Ethanol – C2H5OH – has been made since ancient times by the fermentation of sugars. Zymase, an enzyme from yeast, changes the simple sugars into ethanol and carbon dioxide. All beverage alcohol and more than half of industrial ethanol is still made by this process,” sounds like a pretty decent explanation on what ethanol stands for, as showed on the official website of IndyCar.
Unlike Europe, the North American continent aims to make ethanol the next generation type of fuel in the future. As a result, the United States of America and Brazil are responsible for almost 90 percent of the world's ethanol fuel production (in last year) and have already proceeded to imposing a certain percentage of ethanol in road car gasoline use. While in the US the minimum amount of ethanol in road car gasoline has to be 10% (not all the states are subject to that regulation), in Brazil it's 25%.
As compared to regular gasoline, ethanol is known to produce less power inside the engine because of the energy per unit volume of ethanol (approximately one third of the gasoline-produced one). As a result, the IndyCar officials decided to increase the displacement of their engines in order to maintain a high level of power for their Honda V8s. On the good side, however, using ethanol is a plus in terms of fuel efficiency, as it insures better fuel mileage. So the fuel tanks don't have to be as big as the ones used in the racing series that use gasoline (F1, for example).
FIA World Touring Car Championship
Consequently, the fuel they use is not at all different from the one you can purchase at every gas station worldwide. This is one of the few competitions where the teams are allowed to use both gasoline and diesel to power their engines. The diesel is used by the SEATs (currently), while BMW, Lada and Volvo are going for the gasoline powerplants.
However, as the FIA always tries to implement new technologies that can and will be applicable in the car industry worldwide in the future, this particular championship started to use bio-fuels in order to make the cars more eco-friendly. In 2009, the FIA WTCC teams were obliged to use 10 percent second-generation bio-fuels, alongside 90 percent unleaded gasoline or diesel.
“Ethanol contains oxygen, which helps regular petrol to burn more cleanly and completely. The use of E10 bio-fuel reduces petroleum use by 6.3 per cent and also reduces harmful emissions of carbon monoxide, particulate matter, oxides of nitrogen, exhaust volatile organic compounds and ozone-forming pollutants,” sound the explanation of Luca Perani of PANTA Racing, the company that supplies the WTCC teams with 2G bio-ethanol.
Regular bio-ethanol is actually made out of several types of crops (sugar cane, potato, manioc or corn), while the second generation one is made out of industrial wastes of sugar processing. That aspect is very important from an environmentalism standpoint, as it reduces concerns regarding the replacement of gasoline with bio-ethanol (and the amount of resources needed to produce crops able to sustain a worldwide bio-ethanol based fuel).
In both cases, just as it was ruled in the FIA World Touring Car Championship, the engines are allowed to use 10 percent bio-fuel, depending on their initial fuel (for example, bio-ethanol for gasoline engines and biodiesel for diesel). As we've already covered the bio-ethanol part earlier in this article (IndyCar), let's focus a bit on the biodiesel.
Biodiesel are extracted from either oil- or animal-based fats and is used in standard diesel engines. There are a number of oils that are used to produce biodiesel, such as rapeseed and soybean oils, crops (mustard, flax, sunflower, palm oil, coconut, hemp), animal fats (tallow, lard, yellow grease, chicken fat), algae and others.
The reason why the FIA doesn't want to increase the percentage of biodiesel in most of its series is the constant debate whether gasoline or diesel would be better replaced by bio-fuels. The production of biodiesel would create huge economic disorders, as it would lead to a huge increase of feedstocks production worldwide.
Biodiesel may also be obtained from biomass (biological material resulted from living organisms such as wood or alcohol fuels.
That happens because the companies producing this kind of unleaded fuel are changing the proportions of the gasoline components for improved explosion. However, it wasn't until recently that NASCAR found a way to also protect their engines in the process. Using a high-octane fuel often came with severe damage to the power plant, and the North American racing series had to come up with a plan to stop that in order to reduce engine-related expenditures.
The solution bears the name of SUNOCO 260 GTX, special gasoline that doesn't have any ethers, alcohols or MMT and protects several parts of the engine and fuel system against deterioration. What it does exactly is insure a great level of power inside the engine at compression ratios of 12:1 or more. As explained by the very company who produces it, this fuel (introduced in NASCAR back in 2008) is very good for “many applications that need more detonation protection than street gas provides, yet cannot use a leaded fuel.”
This unleaded fuel is, of course, adding several additives in order to ensure a long-lasting life of up to one year.
NHRA (Drag Racing)
We're not going to get into the whole chemical arguments regarding the nitromethane, but one should consider the fact that it is used as an engine fuel (apart from Top Fuel drag racing) only for rockets and model airplanes. Having said that, it's only natural for the Top Fuel machineries to use this kind of fuel as the air/fuel mixture can burn with much less oxygen than in the case of having gasoline as fuel.
Basically, the air needed to burn up the gasoline inside a Top Fuel engine would have more than 8 times the volume of air needed to burn up nitromethane. It's only natural for the mechanics to try and introduce as much fuel inside the combustion chamber of a cylinder as possible (on the exchange of a smaller amount of air) in order to insure great detonation. In addition, the power generated by nitromethane is more than two times bigger that the one generated by gasoline.
Just to have an idea of how rich the air/fuel mix is inside the engine of a Top Fuel machinery, know that the fuel used by model airplanes rarely contain more than 30% nitromethane. As mentioned before, the amount of nitromethane used in Top Fuel drag racing fuel is a maximum 90 percent (and teams tend to use close-to-maximum proportions in order to maximize engine power).
Everybody knows that the machineries used inside the MotoGP championship are not something you might get to see on the streets. These are prototypes bikes, heavily modified by the MotoGP teams, that don't use even 10 percent of what one may encounter in a road model.
However, the type of fuel used to power the engines of these bikes is not that different from what you may personally purchase at any gas station worldwide. Meaning the composition of the fuel is 99 percent identical to the one in road bikes/cars. It's only the proportion of the components that make the difference, in order to ensure better detonation inside the combustion chamber.