Spool Performance Stage 3 Low-Pressure Fuel Pump — S55
Spool Performance Stage 3 low-pressure fuel pump for the S55 — F80 M3, F82/F83 M4, F87 M2 Competition. A big high-pressure pump is only as good as what feeds it; the factory in-tank (low-pressure) pump runs out of duty on E85 and high boost, and rail pressure drops up top. Spool's Stage 3 adds a boost-activated secondary in-tank pump, roughly doubling low-pressure flow.
What it is
A twin-pump in-tank upgrade: the factory pump plus a second pump that switches on under boost (boost/Hobbs-switch activated), so cruise stays factory-quiet and the system only ramps when you're on it. Spool rates it to support 1,200+ whp, and it's a complete drop-in replacement — no assembly or core return.
Where it fits in the build
Low-pressure (in-tank) side; it pairs with an upgraded high-pressure (DI) pump so the HPFP is never starved. We tune the engine to the fuel system.
Fitment
S55 — F80 M3, F82 M4, F83 M4 Convertible, F87 M2 Competition. Confirm your chassis in the selector.
Sourcing fueling with the tune? The Fueling Kit — S55 bundles the matched parts + calibration for 8% under à la carte.