F-Series AFS Upgrade Kit

Already running a Precision Raceworks F-Series B58 Stage 3 or Stage 4 / 4.5 fuel pump? Convert it into a true stand-alone AFS™ without replacing the pump you already own.

The Precision Raceworks F-Series (F3x/F2x) B58 AFS™ Upgrade Kit 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!

These upgrade kits use the Walbro already mounted on your Stage 3 or Stage 4 / 4.5 assembly as the dedicated auxiliary pump for port injection, while the OEM brushless pump remains dedicated to the DI / HPFP side. Dual-output top hat, dedicated aux lines, and the correct primary-side plumbing separate the two circuits so neither system is fighting the other.

Features & Benefits

• Converts an existing F-Series B58 Stage 3 or Stage 4 / 4.5 pump into a stand-alone AFS™
• Billet Aluminum top hat with 3 high flow fuel ports
• Dedicated auxiliary pump output for port injection
• OEM brushless primary pump remains dedicated to the DI system
  
• Fully adjustable 1:1 scaling billet fuel pressure regulator (included with Stage 3 kit / transferred from your existing Stage 4 / 4.5 kit)
• 10 micron USA made Microglass fuel filter (Ideal for E85) (included with Stage 3 kit / transferred from your existing Stage 4 / 4.5 kit)
• Smooth bore high flow PTFE fuel feed & return lines (AN6)
• Upgraded primary feed line for the DI side (Stage 4 / 4.5 kit)
• 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)
• Compatible with your existing Stage 3, Stage 4, or Stage 4.5 primary fuel pump
• Easily expandable and upgrade-able for more fuel
• All components and parts feature 100% Ethanol Compatibility