Spool Performance Stage 3 Low-Pressure Fuel Pump — S58
Spool Performance Stage 3 low-pressure fuel pump for the S58 — the in-tank side that keeps a Stage 3 build fed. 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. Supplied as a complete drop-in assembly; DIY and built-bucket formats are also available — ask if you'd prefer one.
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
S58 — G80/G81 M3, G82/G83 M4, G87 M2, F97 X3 M, F98 X4 M. Confirm your chassis in the selector.
Sourcing fueling with the tune? The Fueling Kit — S58 bundles the matched parts + calibration for 8% under à la carte.