Riff Raff FRX Fuel Rail Crossover 99-03 7.3L


This kit is a great alternative to a complete fuel system or regulated return kit. Before you need a complete system you can still benefit from equalizing the pressure between the fuel rails. This equalization increases flow to the injectors at a fraction of the cost. We usually recommend a regulated return system at the hybrid injector but with smaller injectors there wasn't a cost effective alternative until the FRX was introduced.

The FRX balances the fuel pressure between the two fuel rails and gives the supplied amount to the entire fuel system and injectors. Riff Raff's FRX is a great alternative to the regulated return fuel system and can supply performance injectors up to 238cc.

This fuel rail crossover kit is a great seller with positive feed back with our customers. This product was designed to eliminate the need to cut your return line and use compression fittings, so that it is a true bolt on system. We have also machined the FRx block to provide from stock to 72 psi of fuel pressure depending on which spring you choose to install it with. By using our kit and eliminating the air in the fuel system you will experience smoother, quieter idle, less cackle, and better throttle response among other things. You will also be increasing your injector life as well.

Protective covers are also pre-installed to prevent chaffing of engine components from the SS braided line. These covers are also great if you want to keep the system looking OE and not draw attention to it once installed.


  • FRx System
  • 3 Springs for adjusting Fuel Pressure
  • Viton O-ring
  • Parker Fuel Sleeve
  • 2 mounting bolts
  • Instructions
Fuel pressure spring settings
  • 55-60 psi silver spring
  • 61-65 psi gold spring
  • 66-72 psi black spring

Tags: Fuel System