Which Fuel to Choose

Here you will find information on which fuel to choose at the fuel pump, based on your car and application. Also, whats Ethanol and is it actually bad?

Octane - What is it? The octane rating was created to represent how resistant a fuel is to engine knock. Engine knock is, simply said, when the fuel in your engine explodes before it is supposed to do so, which can - in extreme cases, cause complete engine failure. Octane is measured in "RON" in Europe and Australia and in pretty much the entire world, you may sometimes find "ROZ", which is just the German abbreviation of RON. The exception is North America, in North America it is measured in "(R+M)/2" or "PON". ("PON" and "(R+M)/2" is the same unit of measurement, just different names.)

"(R+M)/2" stands for "(RON+MON)/2". "MON" is yet another way to measure octane.

RON/ROZ = Reasearch Octane Number/Research-Oktanzahl MON = Motor Octane Number PON = Pump Octane Number

RON and PON, whats the difference? The difference is only the way it is determined. Here is a list of common fuel octane numbers you may see and how they compare. Example: As you can see 95 Octane RON is the same as 91 Octane PON, there is no difference.

Which Fuel to Use? It's rather simple - always use the manufacturers recommendation, well, almost always. There are some exceptions, but first, you're probably wondering where you can find those recommendations.

The manufacturers recommendations on which fuel to use are usually found in the gas cap on a sticker, if they arent there then they could also be in the driver door sill, if they arent there either they may be on your dashboard next to your fuel gauge. If somehow they arent at any of those places, you can check your owners manual, and if all fails, you may just have to look it up online.

Now to the exceptions:

1. If your car has a lot of Kilometers/Miles on it, it may be a good idea to use gasoline with more octane than usually required. This is due to carbon build-up, which can increase an engines compression ratio.

2. If your car is more than 30 years old it may also be a good Idea to run a higher octane gas, this is highly dependant on the engine though.

3. If you add a turbo or super charger or any other type of forced induction to your engine, it is usually a good idea to use at least 98 RON/94 PON or more.

4. If you get your car tuned you should always listen to what the tuner tells you; you may have to run more octane now.

5. If you use your car on any sort of racing/track application you should be fine if using the recommended octane count, altough it may be a good idea to go 1 step up. So for example if your car usually takes 95 octane RON, which is also sometimes called E5 in europe, you may want to upgrade to 98 octane RON.

E-85, Ethanol, Bioethanol - What is it? Ethanol is a liquid that is produced from biomass, such as corn or sugarcane, thus the names bioethanol or "corn-juice" in pop culture. Bioethanol/Ethanol is ethyl-alcohol, which is the same type of alcohol you may find in alcoholic beverages such as beer, vodka, wine and so on.

Pure ethanol has an octane rating of 130 RON / 96 MOZ / 113 (R+M)/2 or PON.

Ethanol can be mixed with gasoline to keep gas prices lower, by using low quality fuel and mixing it with ethanol, the octane rating is increased, this is done all over the world. The most common amounts of ethanol in fuel is 5%, 10%, 15%, 20% and 25%. In the United States, there is also a fuel named "E-85", as the name suggests it consists of 85% ethanol and 15% gasoline. In the world of racing, sometimes pure bioethanol is used, to achieve a high octane count, this would be called E100.

Want to know if the myth about ethanol being bad for your car is true? Click here.

Never run fuel with more than 5% Ethanol in cars that where built before 2001 unless it has been modified to handle more.

Diesel, Biodiesel - What is it? Diesel is any fuel intended to be used in a combustion engine, which ignites without the use of spark plugs but rather ignites from compression alone.

Petroleum Diesel - Made from crude oil.

Synthetic Diesel - Can be made from gas, oil, or biomass.

Biodiesel -Can be made from animal fats or vegetable oil.

You can put both petroleum diesel and synthetic diesel in all diesel cars. Biodiesel can generally also be used by all engines, but you should check with your manufacturer to make sure.