Fuel Rail Crossover™ (FRx)

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7.3L Diesel Fuel Rail Crossover™ (FRx) 99-03 Powerstroke

"The Prescription For Your Fuel System Needs®"

Our 2nd Generation FRx System utilizes Eaton Aeroquip® 304 Stainless Steel Braided lines covered with a groundbreaking protective layer of HYTREL® from DuPont.

The FRx was made to solve the 'deadhead' fuel rail issue on the 99-03 Powerstroke engine by connecting the two heads and allowing a metered return you allow the air another return path, rather than forcing it through your injectors. 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 can experience smoother, quieter idle, less cackle, and better throttle response among other things. You will also be increasing your injector life as well by utilizing the FRx and creating a regulated return back to the tank. 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.

Included:                                                                                        Techical Info:
- FRx System                                                                                  - Exceeds SAE 100R14A
- 3 Springs for adjusting Fuel Pressure                                - Rated for commercially produced B100
- Viton O-ring                                                                                  - Temperature Rated -100˚F to +450˚F
- Parker® Fuel Sleeve                                                                      - Max. Working Pressure 3000 psi
- 2 mounting bolts                                                                           - Minimum Burst Pressure 12000 psi

Fuel pressure spring settings 
55-60 psi  silver spring
61-65 psi  gold spring *Recommended 
66-72 psi  black spring

Riffraff Diesel Performance is committed to 100% Made in the USA. All materials are from USA resources. Every machining step is performed in the USA. Every component is assembled in the USA.


1999-2003 7.3L Powerstroke with stock fuel bowl
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  • 5

    Posted by John on May 19th 2019

    You better have some time and beer! It took much longer than I expected. I had a hard time with the passenger side. The fitting threded into the block no problem but threading the frx on to the fitting really took some time. I had to step away and let my dad try for a while then I finally got it. The rest of the install was very easy. It works very well. The truck is much quieter. With this and the hpx it sounds like a different truck

  • 5
    Beautifully Simplistic

    Posted by Kyle on May 14th 2019

    What a great design. Seemingly simplistic but once you actually look close there is a lot going on in the machined billet block. Amazing quality, even the lines are awesome. Can’t go wrong with made in the USA parts.

  • 5
    Fuel Rail Crossover

    Posted by Bruce Zolman on May 13th 2019

    Installed at the same time as the HPOP crossover so I don’t know which made the difference. I recently install new Garrett GTPR Turbo and the installation of these 2 crossovers gave my SOTP Dyno as much satisfaction as I got from the Turbo installation.

  • 5

    Posted by Anthony on May 5th 2019

    Quiets 7.3 injector cackle alot.

  • 5
    Install and performance

    Posted by Mike DeLoso on May 2nd 2019

    Tricky for larger hands. Very noticeable improvement in injector response and performance.

  • 5
    Money Well Spent

    Posted by Austin on Apr 28th 2019

    I installed Riff Raff Diesels' FRx and noticed a great difference in throttle response. Probably one of my favorite product to come from Riff Raff thus far!

  • 5

    Posted by Brandon on Mar 21st 2019

    Notable better throttle response and smoother idle

  • 5

    Posted by Sean H on Mar 9th 2019

    So much better, smoother and queiter. You can really tell the difference when you purge that air from the rails and push it to your fuel tank return rather than into your injectors.

  • 5
    Product is very quality and simple design.

    Posted by Justin on Mar 7th 2019

    Very good price compared to other fuel return system out there for the 7.3