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
    Quality system

    Posted by Jack T. on Apr 4th 2020

    What better way to pass the time in Rona Quarantine than to work on the truck? Had a leaking passenger side fuel line on my 2000 and saw this as well so decided it was time to upgrade. Plugs are a little hard to get out of the heads so get the socket as well. Fuel pressure is right at 64psi now, and she really is smoother running, and no knock and cackle. Perfect fit, well made kit.

  • 5
    Very important upgrade!!!

    Posted by michael manuel on Apr 2nd 2020

    If you own a 7.3 you haven’t even started to unleash its capabilities if u haven’t installed the FRX as of yet. There is a huge difference in truck without it., it like day and night. It takes away that famous 7.3 crackle that makes us standout. It’s still there in a sense but it’s sounds a lot better. It makes it quieter making the whistle from our turbos a lot more pronounced. Aside from sound the truck on performance end is also distinguished shifts smoothers. Ramping idle is put to rest and it takes off a lot quicker. Do this upgrade if you’re already looking at it, your injectors will love you more and so will the rest of your truck. Pair the FRX with the banjo bolt and cvd upgrades and you’ll pretty much have a brand new motor. RiffRaff is the place I go to get my upgrades and maintenance items they always have good prices, the shipping is always fast, and the service is incomparable. Thanks clay and everybody at RiffRaff for all the efforts and help. You have a lifetime customer here.

  • 5

    Posted by John on Feb 8th 2020

    Excellent build quality, perfect fitment and now fuel pressure is where it should be. Every 7.3 needs this. Super fast postage to Australia. Thanks

  • 5
    Perfect fit, straight forward and relatively easy to install.

    Posted by Dustin Warren on Feb 3rd 2020

    I purchased my early 99' F350 with almost 300k miles. The previous owner had recently done a bunch of big ticket repairs and I'm looking to make this engine better and more reliable than it already is. I installed this with the HPX and notice faster starts, smoother idle and better throttle response. Maybe a design change, but I didn't have to grind away any of the turbo crossover to get it to fit. Great product!

  • 5
    My 7.3 CLACK is gone

    Posted by David Sims on Jan 25th 2020

    I’ve been a 7.3 Super Duty owner continuously since 1999. I’m on my 4th truck and have spent all kinds of money on all sorts of mods. This is one that delivers. My 02 F 350 w 170K runs noticeably smoother and the hard hitting diesel CLACK is gone. Put me down as very pleased. Even my son, a 7.3 owner who does not hand out complements, noted my truck now runs noticeably smoother. Well done Riffraff!

  • 5
    Phenomenal Product!

    Posted by Dustin Warren on Jan 24th 2020

    My truck is over 20 years old and I had no issues removing the square head plugs with a 7mm wrench. The rear, driver's side plug and connection was a little tedious. Excellent product made with excellent materials. The smooth idle and acceleration are amazing!

  • 5
    Fuel Rail Crossover™ (FRx)

    Posted by Robert on Jan 21st 2020

    This is an awesome mod and very well made. Why not upgrade as these 7.3 engines are fuel pressure dependent to operate properly.

  • 5
    Great Product

    Posted by Chris on Jan 21st 2020

    Really easy to install and a great overall product.

  • 5
    FRX crossover

    Posted by Tom Brotzman on Jan 1st 2020

    Wow. If I knew the difference that this would make I’d of put it on a long time ago. Immediately cut down the cackle on my 7.3 and it seems to run smoother accelerating.