Discussion and questions related to the course EFI Tuning Fundamentals
My question is regarding Fuel Rail Pressure and Injector Latency. I understand that with a vacuum reference regulator differential fuel pressure is constant. However, in order for this to be achieved, the rail pressure has to be increased. In my mind it makes sense that as the fuel rail pressure is increased the injector latency should also increase, and therefore this would need compensation as rail pressure increases. However, everywhere I have searched the answer is that the latency is only dependent on the differential pressure, which is constant, so the injector latency does not change as rail pressure increases. This does not make sense to me and I am hoping to find a explanation as to why this is the case.
Actually the injector actually "sees" the differential pressure not the fuel rail pressure relative to atmosphere, so as long as that is unchanged, then the latency is unchanged.
Do a diagram of the forces on the injector pintle (that is what has to move and suffers different latency if it has additional forces to overcome). By keeping the differential pressure constant, the effective force that the pintle has to overcome remains the same -- therefore the latency remains the same.
Understood, thank you