Oxygenated vs Unoxygenated Fuel

As a passionate podium chaser, you know that fuel choice can be critical to the success of your motor racing season. Race fuels offer higher octane levels than pump fuels, but should you opt for an oxygenated or an unoxygenated fuel? Let’s unpack the differences…

SA Oil explains the difference between oxygenated and unoxygenated fuel

What Is Oxygenated Fuel?

Oxygenated fuel, simply put, contains ingredients and additives (‘oxygenates’) that increase the oxygen content, primarily to offset the carbon monoxide created when fuel is burned. These oxygenates are alcohols, like ethanol or methanol.

Regular pump fuels, like that sold in South Africa, is oxygenated, and is available in different octane ratings – in South Africa, there are three pump fuel options that can be found at almost any station – ULP 95, ULP 93 and LRP 95. These oxygenated fuels are used by standard road vehicles. Our neighbour Namibia offers only ULP 95, aside from their diesel options.

These days, oxygenated fuels are unleaded – South Africa phased out leaded fuel in 2006, and modern engines are designed for unleaded fuels, with older engines now using lead-replacement petrol.

Unoxygenated Fuel Explained

Unoxygenated fuel contains such negligible levels of oxygen that it can be referred to as a fuel with a zero-percentage oxygen level. Unoxygenated fuels do not contain additives such as ethanol and oxygen and are thus pure gasoline.

Unoxygenated gasoline isn’t available from the pump at fuel stations in South Africa but is available from race fuel suppliers. Suitable for high-performance applications, unoxygenated fuel is a popular choice for many top-tier international motor racing teams, like those in Formula 1, and local motorsport competitors, like SA Oil’s brand ambassadors, who fuel up with our unoxygenated race fuel for their respective motorsport racing events.

How Oxygenated Fuel and Unoxygenated Fuel Differ

Other than the lack of significant oxygen levels in one and the purposeful boosting of oxygen content in the other, oxygenated and unoxygenated fuels differ in several other ways, including their combustion performance, engine wear, and fuel efficiency.

The Features of The Fuels

Depending on your engine’s compression ratio, the fuel you use can have a huge impact on your engine’s efficiency and wear, fuel economy and power. Knowing your engine well makes it easier to decide between race fuel options, i.e. whether to opt for an oxygenated or unoxygenated fuel.

Here are some basic guidelines to consider:

  • Octane rating correlates with compression rating, and greater compression means a higher temperature within the combustion chamber, resulting in greater thermal efficiency and power
  • Higher octane fuels also have longer hydrocarbon molecules which burn more slowly, reducing premature detonation (or engine knock)
  • Using fuels with a lower octane rating than your engine requires can cause poor engine operation, damage, and stunted emission control
  • Ethanol may boost a fuel’s octane rating, but results in a fuel with less energy than a pure gasoline, which has a higher calorific content
  • Oxygenated fuel means burning more fuel to get more power which, in turn, means less mileage from a tank of fuel.

Benefits of Unoxygenated Fuel

Unoxygenated fuel offers a spectrum of benefits such as:

  • No ethanol – used to boost octane rating, this cheap additive can be a cause for concern, with a host of possible negative side effects
  • Resistance to engine ‘knock’ – the smooth burning of fuel ensures that fuel detonates when it is supposed to and is ignited properly by your engine’s spark plugs
  • Engine protection – air-fuel mixtures in your engine’s cylinders can cause detonation to occur before the top of a compression stroke, and pistons will be forced back down prematurely which can cause major damage
  • Runs cleaner – because it’s a pure gasoline, it contains fewer additives, meaning it leaves less residue in the fuel and engine system. In addition, being unoxygenated (low oxidation capability), it provides corrosion protection.
  • High-performance engines – engines of a higher grade operate much better on a pure gasoline specially formulated for high-performance engines.

Still not sure if unoxygenated fuel is for you? Watch our video on the differences between oxygenated and unoxygenated fuels for a quick overview! 

Want to Know More About Our Unoxygenated Fuel?

SA Oil’s ACCELERATE Special Gasoline is an unleaded, unoxygenated fuel with a 102-octane rating. Find out more about this high-performance fuel or get in touch with us to fuel up…