Octane boosters raise the level of octane in petrol fuel. By raising the level of octane in a car's fuel, octane boosters may improve an engine's power. However, noticeable improvements in power are typically only seen in modern cars with turbo-charged engines. Cars built to run on 98+ octane fuel should see dramatic improvements in both performance and fuel consumption with the use of an octane booster.
Bottled octane boosters utilize anti-knock additives to prevent the onset of knock when added to a car's fuel. This increases the effective octane of the fuel by a significant amount, allowing for improvements in power performance. The amount of octane raised by an octane booster varies among products, with the highest-quality premium octane boosters providing the best results.
Most quality octane boosters feature methylcyclopentadienyl manganese tricarbonyl as the active ingredient. MMT is used in oil refineries to raise the octane of fuel. It does not harm emission control devices and is environmentally friendlier than other anti-knock compounds.
According to HowStuffWorks, although octane boosters are generally safe, many of them do not raise octane levels by a sufficient amount to be effective. Additionally, using quality premium gas is often more beneficial to engine performance.