WHAT TYPE OF FUEL SHOULD I CHOOSE?

Text by Luca Lorenzato, Ferrari Master Technician

One of the most frequently asked questions among the cars enthusiast is related to the type of fuel to be used in the beloved car. Sometimes we receive the same question at the workshop because there is a little bit of confusion and some myths. This is a long topic; we should have a conference more than an article to cover it.

If we look at the present Ferrari production like 296 GTB or 812 Superfast, the 98 RoN (Research Octane Number, or octane rating) is still the recommended fuel, but the 95 RoN E5 and E10 are compatible with the fuel and engine system. What do E5 and E10 mean? “E” stands for Ethanol and the numbers 5 and 10 represent the percentage of alcohol present in the gasoline. Ethanol is an alcohol than can be synthesized chemically as petrochemical or biologically for example through the fermentations of sugars done by yeasts.

There are pros and cons when talking about Ethanol for automotive.

An example of pros, it burns better the gasoline and it has higher numbers of octane. This means that the engine is less prone to build up deposits.

The most significant con is that it works as solvent so it can wash away old residues of fuel closing orifices, it has hygroscopic property and separation property. Hygroscopic means than alcohol can englobe the moisture (water) present in the air, leading at engine malfunction and the build-up of rust inside the fuel tank and fuel circuit, and at the corrosion of the engine materials in general. Separation means that inside the tank, after a prolonged period of inactivity, the gasoline and the Ethanol are separating in two different layers. Alcohol is heavier than gasoline (approx.. 800 gr/L vs 750 gr/L) thus it will lay in the bottom of the tank, making it impossible to start the engine.

So, how could the cars produced in different decades react to these new carburants?

If you have a carburettors cars do not even try! Do not upset Mr. Dell’Orto and Mr. Weber with blended fuels. As an Italian, I’m fairly sure the only sugar cane alcohol they like is the one you can find in the mojito cocktail. Just stick with 98 RoN.

I would apply the same suggestion for cars with mechanical injection, such k-Jetronic or Spica, as all the injection parts made in metal.

For the early electronic injection cars there are almost no problem in burning the blend, but remember that your fuel line and your car are 30 years old-ish. Do not leave any blended fuel in your car for extended periods… and the same suggestion should be applied to all the cars where blended fuels are not specifically reported in the technical information book of the car.

In summary, if we own a sports car, most of the time it is not a daily driver. When we do drive it, let’s try to use only 98 RoN!