Upgraded Fuel Pump

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The factory fuel pressure regulator in your 370z attempts to maintain 52psi in the fuel system at all times.

Using random numbers for example;

If your fuel pump flows 200lph at 52psi, but your engine is consuming 25lph to maintain the speed you are traveling, then your regulator will have to relieve 175lph from the system to maintain 52psi.

If you upgrade to a pump that flows 300lph at 52psi, while your engine is consuming 25lph, the regulator will then have to relieve 275lph from the fuel system.

If you increase the engines fuel consumption to 100lph, the regulator will start to relieve 200lph from the fuel system to maintain 52psi.

So to answer your question: larger pumps can and do push more fuel than stock. But it does not effect your fuel economy because all the extra fuel just gets dumped out by the regulator.

NOTE: when you go large enough on the pump, the regulator and passages in the fuel pump housing will require modification to increase their flow potential so that the regulator is able to do its job. High flowing pumps will overwhelm the regulator and it will struggle to maintain correct pressure. At this point, it WILL effect your fuel economy and the engine can run too rich from fuel pressure exceeding specification.

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