Required for any fuel pump larger than 340 LPH.High-flow fuel pumps draw significantly more current than factory wiring was ever designed to handle. When a fuel pump larger than 340 LPH is run on stock wiring, voltage drop is almost unavoidable. That voltage drop reduces pump output, which can cause fuel pressure to fall exactly when the engine needs it most.When fuel pressure drops, the engine runs lean. Under boost or high load, this can quickly lead to detonation, damaged pistons, or complete engine failure. There is also a serious safety concern. Factory fuel pump circuits are typically undersized for high-current pumps. Pushing that much current through them can overheat the wiring, melt connectors, damage the harness, and in extreme cases cause an electrical fire. This relay kit solves those problems by using a low-current 12V trigger to activate a high-capacity relay that sends full battery or alternator power directly to the fuel pump through properly sized wiring. The result is stable voltage, consistent fuel delivery, and a much safer electrical system.Protect your engine. Protect your wiring. Power your fuel pump correctly. Required for any fuel pump larger than 340 LPH. NOTE: Although this harness's components are rated at a maximum of 40 amps the constant current load should not exceed 25-30 amps. This is because the performance of all electrical components decreases with as temperature increases. It is good practice to locate the fuse and relay as far away from sources of heat as possible. Some electrical loads such as fan motors have a high inrush current upon startup which also has to be factored into this equation. Features - Weatherproof connectors- Heavy 10-gauge automotive-grade copper wire 20' length- 20' positive trigger wire- Heavy-duty 40 amp 630-series weatherproof relay- Weatherproof fuse holder- Silicon grease, spare fuse, wire ties, heat shrink, solder and terminals included- Stainless steel mounting hardware Fitment Universal Fitment
