BP 100 is a high octane leaded petrol that is used to avoid detonation when compression pressures are increased by either high compression ratios or better breathing.

BP 100 has vaporising characteristics that will ensure good mixture preparation using controlled boiling range components.

It should not be used in domestic passenger cars or cars with catalytic converters.

Toluene is a relative of the chemical compound benzene and has a similar odour. As an octane booster and anti-knocking agent, Toluene provides an octane boost of 1 unit for every 5% increase in Toluene to the fuel mixture. The higher octane gained from using Toluene creates a greater ratio in compression to power. Although the benefits of Toluene are many there are a few things to be aware of: at high concentrations, Toluene can damage the fuel systems rubber and plastic components and has also been known to cause sooty spark plugs. Toluene also has no lubrication qualities and can cause damage to fuel pumps and cylinder bores.

Ethanol is sometimes found in race fuels and can make up either a minor or primary amount of the fuel, often racing fuels have an ethanol blend of around 85% although some fuels do contain pure ethanol.

Ethanol creates a high octane fuel with greater compression and expansion ratios with an average (R+M)/2 octane rating of E85 around 100, the benefits of this higher octane are widely published. Additionally, ethanol provides a higher heat of vaporization in comparison to standard fuels, producing almost twice the kilojoules of energy per kilogram of fuel. Vaporization is vital as fuel is mixed with air before combustion can take place, taking oxygen from the atmosphere for its oxidant and assisting in combustion. General Motors have published results of research showing that E85 fuels provided an increase in specific output of almost 15% compared to gasoline. Finally, ethanol is also a renewable and clean energy source and with new advances in ethanol technology arriving regularly there is more potential to be unlocked.

Some hydrocarbons may be particularly suitable as racing fuel components because of their volatility, octane and combustion characteristics, but refineries are not usually capable of separating them from petrol. For example, in the past Formula One teams expended money and resources tailoring a petrol to suit their particular "engine" and application. However, the benefits were relatively small. Note though, that since the regulations have changed, Formula One teams now use commercially available fuel.

The following table summarises some important fuel properties:

* Approximate compression ratios only - depends on engine design and application.

# Air/fuel ratios will vary slightly with fuel composition.

Smaller cylinders with shorter flame path allow higher compression to be used. Very high engine speeds also allow higher compression. For example in racing boats where low speed, high load operation is avoided.

Differences to Regular Unleaded

Ethanol does have a number of unique properties that mean that it needs to be properly formulated and managed to be used as a fuel blend. If these issues are managed correctly, ethanol blends can be safely used in the majority of the Australian vehicle fleet.

One of the key issues is that ethanol is hydroscopic, which means that, unlike petrol, it is attracted to water.

If ethanol blended petrol comes into contact with too much water, “phase separation” can result – this is when the ethanol-water mixture separates from the petrol. If this occurs, it can result in starting problems and, if the fuel system is not flushed in a timely manner, corrosion of fuel system parts.

BP manage this potential issue through 3 key actions:

    Investment in infrastructure and rigorous ongoing water monitoring procedures at both our terminals and retail service stations.

    Adding an industry recognized corrosion inhibitor Octel Starreon corrosion inhibitor DC1 -11 90 ml per 100 ml of ethanol) to our ethanol blended petrol; and

    Only blending ethanol with petrol at or close to a 10% level (the legislated maximum) – ethanol blended petrol is more susceptible to phase separation when blended with lower concentrations.

Ethanol blended petrol prevents deposits from building up within an engine’s fuel system, so clean fuel systems that regularly use ethanol blends tend to stay that way.

On the other hand, ethanol blended petrol can loosen these deposits within older fuel systems (especially in vehicles pre-1986). The loosening of these deposits can potentially lead to the clogging of fuel filters.

BP recommends that older vehicles will benefit from a fuel filter change shortly after consumption of the first fill of ethanol blend fuels. Cleaning of the fuel system is a one off effect and once using the ethanol blend the system will remain clean.

BP also recommends that all vehicle fuel systems are maintained well and that all vehicles benefit from routine inspection as fuel hoses and components can deteriorate with age.