So...now I'm trying to learn more about all this, and I find the following at a link I Googled:
Problem with just adding larger injectors: The higher the fuel pressure, the harder the fuel pump has to work, and more electrical energy is required to open the fuel injectors.
What can go wrong with larger fuel injector upgrades? I often see builds with goals of 500hp and more using 1000cc fuel injectors because of the price jump to a larger injector. They assume they can simply turn the fuel pressure up to increase the flow of the injectors if they run out. While it may be true that 1000cc injectors flow over 1500cc at 100psi base pressure, it is simply not feasible to run that high of a base pressure on a regularly driven vehicle. Remember that a 100psi base pressure is 120psi at 20psi of boost.
At these high pressures, fuel flow is actually reduced in the rest of the fuel system. The resistance to flow in the fuel lines increases as the pressure increases, restricting flow.
Fuel pumps are rated at 43psi of pressure. Your 320lph fuel pump only flows 200lph at 100psi. Most in-tank fuel pumps have a built-in pressure relief valves that open at 100psi, making it impossible for fuel pressure to raise with boost using a 100psi base pressure. Even using a base pressure of 60psi will put serious strain on the fuel pump, causing potentially lean conditions and premature pump failures.
This invites the question...will a larger injector flow correctly at conservative supercharger pressures?
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