tryg
New Member
Octane
Octane, Research Octane Number (RON), rating is a measure of the resistance of petrol to engine knocking.
Engine knocking can damage the engine quite quickly. Some vehicles require a high octane fuel, and many vehicles less than 10 years old can run on lower octane rating fuel safely, but get better economy and power from higher octane fuel.
Octane rating does not relate to the energy content of the fuel. It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where octane is raised by blending in ethanol, energy content per volume is reduced.
It is possible for a fuel to have a Research Octane Number (RON) greater than 100, because iso-octane is not the most knock-resistant substance available.
Racing fuels, avgas, liquefied petroleum gas (LPG), and alcohol fuels such as methanol or ethanol may have octane ratings of 110 or significantly higher – ethanol's RON is 129.
Typical "octane booster" gasoline additives include MTBE (methyl tertiary butyl ether = no you can’t buy it at SuperCheap!), ETBE (is of course, Ethyl tert-butyl ether) and toluene (which you could buy straight, back in the day).
The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise.
Some Antiknock agents
Tetra-ethyl lead
Methylcyclopentadienyl manganese tricarbonyl (MMT)
Ferrocene
Iron pentacarbonyl
Toluene
Isooctane
Triptane
Australias current standard fuel is 91 Research Octane Number (RON) unleaded and most cars sold here since 1986 were built to accept it. However an increasing number of vehicles require 95 RON Premium fuel, while some high performance models require high-octane 98 RON fuel.
An engines octane requirement is usually outlined in the vehicles handbook. The fuel you select for your car must have an octane number at least equal to that specified.
However a fuel with a higher octane number than required will not necessarily produce noticeable benefits, in spite of what some fuel company advertising suggests.
Some vehicles will definitely perform better on high-octane fuels and others will show no obvious benefit. Older vehicles with carburettors are unlikely to benefit unless they are specially tuned for it and even then any gains are likely to be limited.
The benefits for later fuel injected vehicles will depend on the sophistication of the cars engine management system and whether it can make use of the extra octane.
Systems that are capable of adapting fuel and spark maps to the fuel being used are most likely to show improved performance while cars with less smart systems typically wont benefit.
Fuel additives in general
- Ether and other flammable hydrocarbons have been used extensively as starting fluid for many difficult-to-start engines, especially diesel engines
- Nitrous oxide, or simply nitrous, is an oxidizer used in auto racing
- Nitromethane, or "nitro," is a high-performance racing fuel
- Acetone is a vaporization additive, mainly used with methanol racing fuel to improve vaporisation at start up
- Picrate improves combustion, increases fuel mileage
Hybrid compound blends
- Catalyst additives prolongs engine life and increases fuel economy
- Burn rate modifier increases the fuel burn time, resulting in an increased fuel efficiency
- Polymerization increases fuel ignition surface area resulting in increased power from ignition
- Stabilizer/demulsifier/dispersant: prolongs life of fuel and prevents water contamination
- Corrosion inhibitor prevents corrosion of tank and fuel system
- Deposit control additives, acting as detergents, clean the engine
Octane, Research Octane Number (RON), rating is a measure of the resistance of petrol to engine knocking.
Engine knocking can damage the engine quite quickly. Some vehicles require a high octane fuel, and many vehicles less than 10 years old can run on lower octane rating fuel safely, but get better economy and power from higher octane fuel.
Octane rating does not relate to the energy content of the fuel. It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where octane is raised by blending in ethanol, energy content per volume is reduced.
It is possible for a fuel to have a Research Octane Number (RON) greater than 100, because iso-octane is not the most knock-resistant substance available.
Racing fuels, avgas, liquefied petroleum gas (LPG), and alcohol fuels such as methanol or ethanol may have octane ratings of 110 or significantly higher – ethanol's RON is 129.
Typical "octane booster" gasoline additives include MTBE (methyl tertiary butyl ether = no you can’t buy it at SuperCheap!), ETBE (is of course, Ethyl tert-butyl ether) and toluene (which you could buy straight, back in the day).
The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise.
Some Antiknock agents
Tetra-ethyl lead
Methylcyclopentadienyl manganese tricarbonyl (MMT)
Ferrocene
Iron pentacarbonyl
Toluene
Isooctane
Triptane
Australias current standard fuel is 91 Research Octane Number (RON) unleaded and most cars sold here since 1986 were built to accept it. However an increasing number of vehicles require 95 RON Premium fuel, while some high performance models require high-octane 98 RON fuel.
An engines octane requirement is usually outlined in the vehicles handbook. The fuel you select for your car must have an octane number at least equal to that specified.
However a fuel with a higher octane number than required will not necessarily produce noticeable benefits, in spite of what some fuel company advertising suggests.
Some vehicles will definitely perform better on high-octane fuels and others will show no obvious benefit. Older vehicles with carburettors are unlikely to benefit unless they are specially tuned for it and even then any gains are likely to be limited.
The benefits for later fuel injected vehicles will depend on the sophistication of the cars engine management system and whether it can make use of the extra octane.
Systems that are capable of adapting fuel and spark maps to the fuel being used are most likely to show improved performance while cars with less smart systems typically wont benefit.
Fuel additives in general
- Ether and other flammable hydrocarbons have been used extensively as starting fluid for many difficult-to-start engines, especially diesel engines
- Nitrous oxide, or simply nitrous, is an oxidizer used in auto racing
- Nitromethane, or "nitro," is a high-performance racing fuel
- Acetone is a vaporization additive, mainly used with methanol racing fuel to improve vaporisation at start up
- Picrate improves combustion, increases fuel mileage
Hybrid compound blends
- Catalyst additives prolongs engine life and increases fuel economy
- Burn rate modifier increases the fuel burn time, resulting in an increased fuel efficiency
- Polymerization increases fuel ignition surface area resulting in increased power from ignition
- Stabilizer/demulsifier/dispersant: prolongs life of fuel and prevents water contamination
- Corrosion inhibitor prevents corrosion of tank and fuel system
- Deposit control additives, acting as detergents, clean the engine
