F-Series B58 High Performance Fuel Pump
Boost and ethanol both ask for more fuel than a stock in-tank pump can move, and that is where the factory setup runs out of headroom on a tuned car. This B58 low-pressure fuel pump is a bucketed and bucketless hybrid that pairs the OEM brushless pump with a proven Walbro unit outside the bucket, lifting in-tank supply well past standard while staying completely drop-in. Nothing is cut, stripped, or crimped: the system drops into the tank, the factory pump goes back in, and the boost-referenced Walbro wakes up only when you call for it.
How the Hybrid Bucket Works
The design keeps the primary pump fully submerged in fuel no matter how low the tank runs or how hard the car corners, so pressure holds through long pulls and high-g turns alike. On pump gas or straight E85, hybrid B58 low-pressure fuel pumps built this way feed the high-pressure side without the surge and starvation that catch out a lone stock pump. A 13 psi boost-reference switch, the Hobbs switch, brings the second pump online under load, so idle and cruise stay factory-quiet and daily manners are untouched.
What Every Stage Shares
Every kit is genuinely plug-and-play, and for reference, the factory pump moves 3.55 LPM at 72 psi (5 bar), which the stages below leave far behind. In the box, each version includes:
- Genuine OEM fuel pump bucket assembly
- Pre-assembled OEM brushless pump with a mounted Walbro
- Fuel sending unit (fuel level sensor)
- Plug-and-play boost reference harness, with zero cutting, stripping, or crimping
- 13 psi boost reference (Hobbs) switch
Stage 3
Rated at 5 liters per minute, the Stage 3 hybrid runs the OEM brushless pump in the bucket with a Walbro 450 (F90000274) outside it. It supports up to 900 whp and is rated for 850 whp on 100 percent E85, with no aftermarket EKP required. It drops straight in using the shared parts listed above.
Stage 4
Stepping up to 5.5 liters per minute, Stage 4 keeps the OEM brushless and Walbro 450 (F90000274) pairing but supports up to 1,000 whp, rated for 950 whp on 100 percent E85. Alongside the shared kit, it adds a fuller supply upgrade:
- Upgraded AN-6 fuel feed lines with fuel pressure regulator and return lines
- New in-line fuel filter
Stage 4.5
The top step delivers 6 liters per minute by swapping in a larger Walbro 525 (F90000285) alongside the OEM brushless pump. It supports over 1,000 whp and is rated for 1,000-plus whp on 100 percent E85, again with no aftermarket EKP required. Like Stage 4, it includes the AN-6 feed lines, the pressure regulator and return lines, and a new in-line fuel filter.
Fitment Across the F30 Range
Because the in-tank pump assembly is shared across the F30-generation cars, this kit is not tied to a single model. Owners searching for a stronger BMW 320i fuel pump often land on the very same in-tank bucket used across the platform, so the upgrade path is common ground for many chassis. Confirm your exact model and tank before ordering, so the correct bucket and sending unit ship for your car.
Drop-In Installation
Fitting needs no fabrication. Drop the pump system into the tank, insert the factory pump, slide the bucketless bracket onto the side of the bucket, and close the top hat. With the plug-and-play harness, there are no wires to cut or splice, so swapping in a fuel pump BMW 320i owners and B58 drivers alike can trust takes little more than the time to open the tank. Once it is in, the extra flow is there the moment boost climbs.
