The Stoichiometric Ratio of the fuel being used is required to calculate the correct amount of fuel to be delivered for a given air mass. The stoichiometric ratio is also used to calculate the AFR Average runtime value and by PCLink to do automatic Lambda to AFR conversion (U key).
Below are some stoichiometric ratios of common fuels:
Fuel Type |
Stoichiometric Ratio |
Petrol/Gasoline |
14.7 to 1 |
Ethanol |
9.0 to 1 |
E85 (85% Ethanol, 15% Petrol) |
9.7-9.8 to 1 |
Methanol |
6.4-6.5 to 1 |
Diesel |
14.6 to 1 |
Liquefied Petroleum Gas (Propane) |
15.5-15.8 to 1 |