Definition
Higher ethanol content increases octane but requires more fuel delivery.
Flex-fuel tuning adapts to varying ethanol percentages automatically.
Automotive Wiki
Fuel
Ethanol Content
The percentage of ethanol in pump fuel, varying seasonally on E10 and flex-fuel blends.
Related terms
- Fuel InjectorAn electronically controlled valve spraying atomized fuel into the intake port o…
- CarburetorA mechanical device mixing fuel and air using jets, venturis, and throttle plate…
- Direct InjectionFuel injection directly into the combustion chamber at high pressure.
- Port InjectionFuel sprayed into the intake port before the valve, mixing with incoming air.
- Octane RatingA measure of fuel resistance to knock under compression and heat.
- E85A blend of roughly 85% ethanol and 15% gasoline offering high knock resistance.
Category: Fuel · Updated August 31, 2026