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
    Awesome product!

    Posted by Robert Zimpel on Dec 8th 2019

    Well built awesome product that fit perfectly! Install wasn’t too bad and would recommend doing if you’ve got the rest of the top end of your 7.3 tore apart, just do it and be done with it. Also recommend ordering the 9/32 socket to remove the plugs made the removal easy and used a small punch like others recommend to use on passenger side plug. Riffraff has all the best parts and add on’s for 7.3’s at the best price!

  • 5

    Posted by Austin on Nov 18th 2019

    Well built quality part. Didn't help perdels on #8 like I hoped (roughly 5%), but may have made the truck a smidge more quiet? Can't be a bad thing circulating fuel instead of dead heading it though so still glad I installed this part. This paired with HPx and an original black CPS quieted the truck down and dropped perdels on #8 to a very respectable level (around 2.2%). P. S. Do NOT underestimate the major PITA of removing the plugs in the heads to install the FRx. Use lots of penetrating oil prior to attempting to remove the plugs...as in days ahead of time.

  • 5
    Easy install / works as advertised

    Posted by Ryan Rutledge on Oct 31st 2019

    I’m very glad I did this upgrade. I found my old fuel pressure return spring was distorted when I upgraded to the included gold spring. I’m not sure if it actually quieted down how my engine runs, but the installation was very straight forward. I installed this onto my f-550 7.3L mechanics truck in hopes of helping with a possible engine misfire. But, thought it could help my new fuel injectors last longer if I had to replace them. My truck currently has 226k miles on it now. My other f-350 7.3L also has this Fuel return system on it. Neither of which seem to have any problems.

  • 5

    Posted by Grant on Oct 17th 2019

    Great product! I’m no mechanic and was able to get it installed successfully. Engine is noticeably quieter.

  • 5
    Should of done this a while ago.

    Posted by RIck C. on Sep 10th 2019

    Put this on a few weeks ago and cant believe the difference in how much quieter the truck is now. Also a pretty noticeable power difference with the new fuel pressure spring. Overall pretty happy just curious to see how long the hose that runs to the back of the engine next to the up pipe and turbo last. SIde note the 7.3 can be pretty noisy at highway speeds this seems to really mellow the truck out and calm some of the cackling down. I like it:).

  • 5
    Frx crossover

    Posted by Robert Ordal on Sep 9th 2019

    Increase in fuel mpg., and smother running motor.

  • 5
    RiffRaff FRX

    Posted by Ryan on Sep 2nd 2019

    Works great! Good alternative to a regulated return system. Another quality product from RiffRaff!

  • 4
    Works good motor idles better

    Posted by Jason on Sep 1st 2019

    Alittle of a pain in the butt. Definitely need 9/32 square socket from riff raff. Hard to get to the passenger plug. What i did was weld a nut to the top of socket so i could use a wrench. Rachet doesnt fit in there. Took about an hour and a half. Start to finish.

  • 5
    Smooth and Quiet

    Posted by Henry Baker on Jul 13th 2019

    3 out of 5 on install difficulty, not really too bad. Really smoothed out my old Powerstroke and starts faster too. Overall I would recommend this to any 7.3 owner.