Gasoline additives may increasegasoline'soctane rating, thus allowing the use of highercompression ratios for greater efficiency and power, or act ascorrosion inhibitors orlubricants. Other additives includemetal deactivators,oxygenates andantioxidants.

Some additives are harmful and are regulated or banned in some countries.

• Sugar, as seen inThe Passionate Stranger (1957) andpopularly believed to damage the engine.^[1][2][3]

• Oxygenates
  • Alcohols:
    • Methanol (MeOH)
    • Ethanol (EtOH); see alsocommon ethanol fuel mixtures
    • Isopropyl alcohol (IPA)
    • n-butanol (BuOH)
    • Gasoline gradet-butanol (GTBA)
  • Ethers:
    • Methyl tert-butyl ether (MTBE), now outlawed in many states of theU.S. for road use because ofwater contamination.
    • Tertiary amyl methyl ether (TAME)
    • Tertiary hexyl methyl ether (THEME)
    • Ethyl tertiary butyl ether (ETBE)
    • Tertiary amyl ethyl ether (TAEE)
    • Diisopropyl ether (DIPE)
• Antioxidants, stabilizers
  • Butylated hydroxyanisole (BHA)
  • Butylated hydroxytoluene (BHT)
  • 2-tert-Butylphenol
  • 3-tert-Butylphenol
  • 4-tert-Butylphenol
  • 2,4-Dimethyl-6-tert-butylphenol
  • 2,6-Di-tert-butylphenol (2,6-DTBP)
  • 2,4,6-Tri-tert-butylphenol (2,4,6-TTBP)
  • tert-Butylhydroquinone (TBHQ)
  • p-Phenylenediamine
  • N,N'-Di-2-butyl-1,4-phenylenediamine
  • Ethylenediamine
• Detergents; see alsoTop Tier Detergent Gasoline
  • Amines aka "nitrogen enriched"
    • Polybuteneamine (PBA)
    • Polyetheramine (PEA); see alsoTechron
    • Polyisobutyleneamine (PIBA)
• Antiknock agents
  • Tetraethyllead (TEL), nowbanned almost everywhere forcausing brain damage.
  • Methylcyclopentadienyl manganese tricarbonyl (MMT) is a neurotoxic substance and is fatal if swallowed/inhaled and causesmanganism.^[4]
  • Ferrocene
  • Dimethyl methylphosphonate
  • Toluene
  • Isooctane
  • Triptane
• Leadscavengers (for leaded gasoline)
  • Tricresyl phosphate (TCP) (also anAW additive andEP additive)
  • 1,2-Dibromoethane
  • 1,2-Dichloroethane
• Fuel dyes, most common:
  • Solvent Red 24
  • Solvent Red 26
  • Solvent Yellow 124
  • Solvent Blue 35
• Fuel additives in general
  • Ether and other flammable hydrocarbons have been used extensively asstarting fluid for many difficult-to-start engines, especiallydiesel engines
  • Nitromethane, or "nitro", is a high-performance racing fuel
  • Acetone is avaporization additive, mainly used withmethanol racing fuel
  • Butyl rubber (as polyisobutylene succinimide,detergent to prevent fouling ofdieselfuel injectors)
  • Ferrouspicrate, used in diesel fuel to increase fuel conversion efficiency and reduce emissions
  • Two-stroke oil, for lubrication ofsmall engines reliant on crankcase compression
  • Upper cylinder lubricant, extensively advertised but of unproven value

• Nitromethane can increase thecetane number of diesel fuel, improving its combustion properties
• Nitrous oxide, or simplynitrous, is anoxidizer used in many forms ofmotorsports such asdrag racing andstreet racing.

Fuel additives in theUnited States are regulated undersection 211 of theClean Air Act (as amended in January 1995). TheEnvironmental Protection Agency (EPA) requires the registration of all fuel additives which are commercially distributed for use in highway motor vehicles in theUnited States,^[5] and may require testing and ban harmful additives. The EPA also regularly reviews the health and net economic benefits of Clean Air Act policies.^[6]

The act also requiresdeposit control additives (DCAs) be added to all petrol. This type of additive is adetergent additive that acts as a cleansing agent in small passages in thecarburetor orfuel injectors. This in turn serves to ensure a consistentair and fuel mixture that will contribute to bettergas mileage.

• metering pumps
• Oil additive
• Greenwashing

• ARRC Auto Repair Reference Center. Point 5 Technologies. Accessed via EbscoHost on November 27, 2009
• EPA: List of Registered Gasoline Additives (Under 40 CFR Part 79)