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
    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.

  • 5

    Posted by Jonathan Lo on Jul 5th 2019

    A little bit of a pain to install. Especially the passenger side head port. Other than that, it looks great. I had the HPX installed prior to installing this, so I wasn't sure where to rout the driver's side head fitting. Shortly afterwards, I ended up pulling the turbo for some upgrades in that. That would have made the install a million times easier. I'm not quite sure on difference in performance, but the wife says my engine doesn't cackle nearly as much. For "noise reduction" I've done the FRX and HPX.

    CVD and Banjo bolts will be next. I just wish I would have done everything at once.

  • 5

    Posted by Diesel Dave on Jun 14th 2019

    This crossover is not too difficult to install, but do be patient as installing the fittings in the heads is tight. The fuel block with spring is a bit of a challenge too, tight to install and keeping the o-ring and spring in place too. This is a modification Ford should have designed and installed at the factory.

  • 5

    Posted by Joseph on May 27th 2019

    So far so good it has quieted down the single shot injectors, now just waiting on tuner to be re-flashed had a minor hiccup.

  • 5

    Posted by Jeff on May 24th 2019

    Installation takes a few hours due to the location of the test plugs and fuel lines. Used the included thread sealant and had no leaks on pressurizing the system. The contribution test now shows all injectors equal.