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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®"

We are now shipping our 2nd Generation FRx System that 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 154 | Next

  1. This Was A "No Doubt" Purchase 5 Star Review

    Posted by on Oct 20th 2016

    The FRx prevents a "dead-end" in the fuel-rail, which starves the last injector in each rail of fuel...Especially under load! The included pressure springs are higher quality then OEM.. The fitting that goes to the rear of the engine (driver side) is close to the turbo up-pipe, so I wrapped the fitting with exhaust wrap to shield the heat away.

  2. Simple installation 5 Star Review

    Posted by on Oct 19th 2016

    Fairly easy install. On my engine I removed the check valves from the heads and removed the check valve and drilled out the screen in order to increase the fuel flow.

    Accomplishes the same thing as Driven Diesel's regulated return at a much lower cost.

  3. These guys know there Powerstrokes 4 Star Review

    Posted by on Oct 18th 2016

    Great mod, quieter, faster starts, super happy I did it. Nicely made part, you can really see the precision machining job, thumbs up:

  4. Best regulated return yet 5 Star Review

    Posted by on Oct 18th 2016

    Pretty easy install, just take your time. Dropped right in like it was made to be there. Much quieter idle, and after putting 3 tanks of fuel through I am seeing almost 2 mpg more. Recommend it to all 7.3 guys.

  5. Needs a bit of work. 3 Star Review

    Posted by on Oct 18th 2016

    Everything fits in the end but I'm picky after 42 years as a mechanic. The length of the hoses, the angles of the fittings at both the bowl and the heads and the orientation of the hose ends could use improvement. Also a more flexible hose would be easier to work with.

  6. Great product 5 Star Review

    Posted by on Oct 3rd 2016

    Engine is idling smoother, but did hpx addition at same time.

  7. Frx to solve your fueling issues 4 Star Review

    Posted by on Sep 20th 2016

    Overall ease of installation, instead of unbolting the fuel
    Bowl I found it easier to disconnect both lines off the bowl itself. Biggest issue I had was getting be fitting into the driver side head, extremely tight fitting area. If you want true increased throttle response, and overall better running engine buy the Frx. Installed the recommend spring and you'll be golden.

  8. Great Product - Worth the effort 5 Star Review

    Posted by on Sep 4th 2016

    This is a very well made product. The instructions are well written and easy to follow. The installation can be challenging, but only because the ports may be difficult to get to. Once the pipe plugs are out, it goes pretty smoothly. The results are definitely worth it. The engine idles much more smoothly. Note that I also installed the oil crossover at the same time, so it's difficult to know how much each device contributes to the end result - but taken as a whole, it was worth the money, time, and effort.

  9. Works Great 5 Star Review

    Posted by on Aug 30th 2016

    Definitely less noise at start up and a smoother idle. I would have liked to see a little more information on the different spring choices that come with it.
    Thanks Guys

  10. Awesome Product 5 Star Review

    Posted by on Aug 19th 2016

    FRX is awesome. Not sure what Ford was thinking by not making this a standard product, but thanks to Riff Raff for bailing them out again.

Showing reviews 1-10 of 154 | Next