F-Series Auxiliary Fuel System B58/S55

The Precision Raceworks F-Series (F3x/F2x) B58 Stand Alone AFS™ is the highest performing and most stable low pressure fuel system on the market! Forget about how things have been done and embrace the benefits of dedicated fueling for your port injection!

Since direct injection came out on modern BMW's, enthusiasts have been adding port injection. With this came the need to upgrade the low-pressure fuel system to keep up. Historically this was done by increasing the output of the main fuel system. Unfortunately, the main fuel pump is controlled using PWM by a factory programmed controller designed to reduce output when target fuel pressure (typically 5 bar) is exceeded, creating a constant battle when pumps are added or upgraded. This limits upgraded fuel pumps from performing to their full potential.

Additionally, the high pressure pump control system dumps fuel back into the low pressure system at high pressure low volume resulting in oscillations of the low pressure fuel system. Because of this the DI system in the car is required to constantly make corrections to keep target AFR in check.

With this stand-alone low-pressure fuel system dedicated to your port fueling that is a thing of the past! Get rock solid fuel pressures at any pressure, run fuel pressures which are 1:1 scalable to boost pressure, flow more fuel with dedicated lines, run smaller injectors and still get more fuel than you did with large injectors (allowing for higher resolution), put less demand on the car’s DI system to correct for fluctuations in pressure, even your tuner will be grateful as the system makes tuning of port fueling even easier and more accurate, the list of benefits goes on and on!

Features & Benefits

• Billet Aluminum top hat with 3 high flow fuel ports
• Dedicated fuel pump for port injection system
  
• Fully adjustable 1:1 scaling billet fuel pressure regulator
• 10 micron USA made Micro-glass fuel filter (Ideal for E85)
• Smooth bore high flow PTFE fuel feed & return lines (AN6)
• All billet connections for both fuel line fittings and top-hat
  
• Configurable pump activation harness (see instructions for more details)
• Increased injector flow (when using 1:1 regulator feature vs static)
  
• All components and parts feature 100% Ethanol Compatibility

Models & Configurations

• AFS.425
  The AFS.425 dedicated AFS™ comes with all necessary components to provide dedicated fuel system for port injection. Featuring a single Walbro 450 (F9000274) fuel pump which flows 425LPH at 3 bar.
• AFS.450
  The AFS.450 dedicated AFS™ comes with all necessary components to provide dedicated fuel system for port injection. Featuring a single Walbro 525 (F90000285) fuel pump which flows 450LPH at 3 bar.
• AFS.460
  The AFS.460 dedicated AFS™ comes with all necessary components to provide dedicated fuel system for port injection. Featuring a single Walbro 535 (F9000295) fuel pump which flows 460LPH at 3 bar.

If your tuner wishes for you to have Solid State Relays, we recommend using our kit here. 

*At time of install some wiring in the car will need to be cut and spliced to connectors included in this kit.

**The AFS™ kits are designed for use with a port injection kit where the fuel rail is mounted above the manifold. To run this kit with a plate style PI, please reach out for modification instructions.