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Riffraff Diesel Performance Inc, Engines - Supplies, Equipment & Parts, Eagle Point, OR


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Fuel Rail Crossover™ (FRx)

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Your Price:
$188.81 (You save $8.56)
Part Number:

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 will 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.


- FRx System
- 3 Springs for adjusting Fuel Pressure 
- Viton O-ring 
- Parker® Fuel Sleeve
- 2 mounting bolts
- Instructions

Techical Info:
- Exceeds SAE 100R14A
- Rated for commercially produced B100
- Temperature Rated -100˚F to +450˚F
- Max. Working Pressure 3000 psi
- Minimum Burst Pressure 12000 psi

Fuel pressure spring settings 

55-60 psi  silver spring
61-65 psi  gold spring
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.


Product Videos

How To: Riffraff Diesel Fuel Rail Crossover (FRx) (04:01)
How to install the Riffraff Diesel Fuel Rail Crossover (FRx) on your 7.3 powerstroke. Purchase: http://www.riffraffdiesel.com/fuel-rail-crossover-frx/ PDF Instructions: http://www.riffraffdiesel.com/content/RESOURCES/Riffraff_Diesel_FRx_Instructions.pdf
  • How To: Riffra...
    How to install the Riffraff Diesel Fuel Rail Crossover (FRx) o...
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Product Reviews

Showing reviews 1-10 of 225 | Next

  1. I like having the smoother running engine 5 Star Review

    Posted by on Jun 1st 2018

    I just got done upgrading my injectors, and with this RFX it was fast to bleed out the system and get the truck running again. It also seems to run a bit quieter and smoother.

  2. Perfect Upgrade 5 Star Review

    Posted by on May 31st 2018

    The RRD FR-X is a great way to upgrade your fuel system and get the benefits of a regulated return. The fit is perfect and easy to install.

  3. Theory makes sense 4 Star Review

    Posted by on May 27th 2018

    I like the theory that allowing air to find an alternate exit route other than the injectors will prolong the life of the injectors as presumably does the regulated 65psi.
    I have done all the standard mods separately and spaced apart to observe the results. The FRX has been the last and the biggest pain.
    The FRX hoses don't have swivel fittings which would be the cats meow when trying to connect the hoses to the fittings in the head. Don't let this project intimidate you though, just be patient. Review and follow the video and you will be fine. Here are some recommendations from my experience; 1. when you remove the EBP, clean the carbon and crud from it while it is out, 2. place a rag or paper towels below where the fittings install blocking their route to the ground or hiding places when you drop the fittings when installing, you won't have to look so far to retrieve them, 3. The supplied small rubber o-ring or washer goes on the fuel line you removed from the stock regulator, slide the nut back remove and discard the old one and replace with the new one. 4. before opening the thread sealant, squeeze and work back and forth the contents in case the sealant has separated.
    All and all I can't tell a difference in performance or sound, but I like and believe in the theory behind it. The biggest noted difference in sound (noise) came from the HPX (quality and easy install), and replacing the CVD's, I made my own fuel lines and used AN fitting where the CVD's go. I wish there were dyno and real performance and power results with each of these mods, instead of just sound and seat of the pants feel.

  4. Smoother and quieter 5 Star Review

    Posted by on Apr 29th 2018

    Little tough getting to the plugs to get out but that’s not a riff raff issue. Just unbolted the a/c compressor and moved aside. I went with the black spring. Why did I wait so long to do this mod?

  5. Nice piece 5 Star Review

    Posted by on Apr 26th 2018

    Trucks idle is rock solid. An dont let the install intimedate you it wasnt bad at all on my 2001F350.
    Feel it alot at idle, but i believe it helped support higher rpm runs too. As my truck lives a little more above 3K than i guess it should. But drive it like you stole it!! Cant go wrong with this FRx fit is nice an its operated flawlessly. Just watch for abrasion points. Some loom or jacket is a nice piece of mind during install.

  6. Like a charm 5 Star Review

    Posted by on Apr 24th 2018

    Goes on flawlessly with the motor out of truck haven't go to see if it made a difference in the truck due to motor still out. Fits perfect and looks good

  7. quality product 5 Star Review

    Posted by on Apr 23rd 2018

    installed the frx with the gold spring. its a great product, really quality made. The fittings are a serious pain to get started in the heads but its not a riff raff product problem. I didn't notice any quieter running. the motor is noticeably smoother which in essence makes it seem quieter. Throttle response is crisp. I did the hpx a couple weeks ago just to be able to see a difference. I highly recommend the hpx to correspond with the frx. Still have cvd fittings and banjo bolts to install before the fuel upgrade is complete.

  8. High quality part 5 Star Review

    Posted by on Apr 17th 2018

    Installed this with the HPx and the truck runs smoother and quieter now. Great job by Riffraff on the design and manufacture of quality parts to upgrade my powerstroke.

  9. Great upgrade for the price 5 Star Review

    Posted by on Apr 15th 2018

    Installed along with the HPX, both noticeably quieted engine down and smoothed up at idle.

  10. Great products as always 5 Star Review

    Posted by on Apr 15th 2018

    All around great product

Showing reviews 1-10 of 225 | Next