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Injection Time Fuel Model

EFI Tuning Fundamentals

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Hi,

I have a question regarding the density calculation as it pertains to the Injection Time Based Fuel Model. In the table does the injection time displayed in the table include the Speed Density calculation for mass? Or is the Pulse Width that is displayed represents before the Speed Density Calculation (Before the Ideal Gas Law is multiplied)

Thank you

If you're dealing with an ECU that uses a direct table of injection time values then that is what will be sent to the injector - There's often nothing more to it than that and we simply have MAP as a load axis to point the ECU to the correct place in the fuel table. Others go a step further and include a background fuel calculation which accounts for MAP (basically this is just a case of 'if we double MAP then we need to double the fuel in order to maintain a consistent AFR'). It's VE-based fuel models where the ECU calculates air mass based on the ideal gas law and the engine parameters you've entered.