How much air vs. fuel are you burning? The air fuel ratio is an important factor in the power and risk levels of your engine. The air fuel ratio of your engine can be your key to unlock precious extra power or the formula for disaster.


   Controlling AF ratios
The air fuel ratios for your engine are controlled by the car’s ECU. A factory ECU will maintain safe air fuel ratios whenever possible. ECU products can be purchased to adjust your air fuel ratios. ECU chips are available in a variety of AF ratios settings. Products such as EMS allow you to adjust your AF ratios via a controller. These products and your factory ECU will keep the air fuel levels at the designated setting as long as the fuel system can support the fuel needs.


   Fuel System
Fuel demands go hand in hand with increased air needs. As your system pushes more and more air it will require more and more fuel. Be sure to monitor your AF ratios with the use of an AF meter to make sure your fuel system is supporting the fuel needs of your system. It is important to plan your fuel system upgrades along with the rest of your engine building. If your fuel system can not support the fuel flow needs your engine will lean out and can be cause for severe engine stress and damage.


Air Flow vs Fuel Flow Capacity
 


   Rich
Rich is a mixture with more fuel than air. This is normally a safer system. Factory ECUs are set to a rich AF ratio. More fuel keeps the engine stress level low but does not maximize power output.

   Lean
A mixture of more air than fuel is called lean. Pushing the AF ratio in this direction can yield more power at a higher risk. The leaner you go the more risk is incurred. There is always point in which the risk of damage will surpass the power gains.

   Neutral
A neutral ratio is an even mix of air and fuel. This is still safe setting for operation and will produce better power than a richer setting.


Note: The information on this site is strictly game theory and should not be applied to your real car. Nitto is not responsible for what you do to your own car.

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