DIY - RS4 135 Bar Fuel Pressure Valve (FPV)

[junker]

Today, I was able to get this part installed without pulling the intake manifold, or the throttle body. I'm not going to tell you it was a piece of cake, because it wasn't. It was a PITA. But, I think I can put enough tips together to make it less painful for anyone else wanting to install this part. My rebuilt HPFP will be in later this week, and I will use that opportunity to take several key photos to put this together. I'll also list the parts needed, and a few helpful tips. Stay tuned! :thumbsup:

Draft Information

RS4 Valve Part #: 079130757

1. Bleed off HPFP pressure using bleed valve
2. Remove HPFP line on the right
3. Remove T30 Torx on front bottom right
4. Release fuel line clamp
5. Loosen T30 Torx for the fuel lines on top of the manifold
6. Use 14mm crow foot to remove fuel line from OEM FPV
7. Use 17mm crow foot to remove the FPV
8. Use leverage with wrench at front of intake manifold to pull fuel line from FPV so it can be removed
9. Thread RS4 FPV into fuel rail
10. Tighten with 17mm crow foot
11. Tighten fuel line to FPV using 14mm crow foot
12. Tighten fuel line on HPFP
13. Tighten 3 fuel line T30 on the intake manifold
14. Turn ignition to accessory to prime fuel rail and inspect for any fuel leakage. Tighten anything as required.
15. Start and let idle. Again check for any fuel leakage or any other issues
16. Enjoy your upgrade!

Disclaimer: I assume absolutely no risk for any injury or damaged caused by following this DIY. Always use all safety precautions and common sense to make sure you do not damage anything or hurt yourself. You have been warned.

 

[penpal]

just wondering in which tune do you run into the limit of the stock FPV?

 

[The Fed]

Being a PITA is still easier than pulling the manifold and risking needing all new injector seals.

 

[mrbikle]

i wish you could just get the teflon seal. I hate spending 12-15 bucks an injector on that crap.

 

[Tmsracing37]

just wondering in which tune do you run into the limit of the stock FPV?

K04 and Big turbo tunes requesting 128-130 bar have seen benefits from RS4 valve vs OEM valve

 

[bryangb]

This is on my long to-do list

 

[junker]

My feeling on this part is that is should be performed on any tune that requests over 127 bar.

The fuel rail tolerance is +/- 10 bar, but in healthy system only seems to vary 2-3 bar. Who is really to say that your current valve is not fluttering and cracking all the time at the prescribed valve pressure to prevent the fuel rail from overcharging? I'm not convinced it would even be obvious on a VCDS fuel rail pressure log.

The analogy I have used is between voltage and current with electricity, and with pressure and flow rate with plumbing. It is very possible that an aftermarket HPFP can flow enough volume (up to 40% more) to keep the rail charged at the cracking pressure, while the excess is coming back along the return line and none are the wiser.

Do you really think a 129.99 bar tune is not opening a 130 bar stock valve? Wow that valve must be pretty damn amazing to stay closed at 129.99 but open at 130.00!

It's possible that running an OEM valve is sufficient even though it is relentlessly getting cracked open. The rail is safe from exceeding 130 bar, and for the most part that is probably its primary purpose. But could this be harder on your cam and follower if the pump is needlessly cycling fuel through the fuel rail because your valve is opening? :iono:

But if you are running a 129.99 or greater tune I think it makes a complete sense to use an upgraded valve that is a few bar above the request value.

My valve is in and my APR HPFP will be here later this week, and then it's off to GIAC to go with an extreme K03 file.

I'll ask Austin about the valve when I meet up with them, but take a look at their list of K04 tunes and they are specifically listing it as a component on some HO tunes:

http://www.giacusa.com/programs.php?mpid=185

Higher fuel rail pressures should reduce injector duty cycles and improve atomization, combustion, and air-fuel charge cooling.

I'll try to collect data and take logs to give us some better info to work with. :thumbsup:

 

[NJdubber]

I actually like that GIAC gives you an opportunity to get flashed according to your setup..instead of that generic shelf tune..

 

[junker]

I actually like that GIAC gives you an opportunity to get flashed according to your setup..instead of that generic shelf tune..

There are a few things I know about, and I'll see what I can share after we go with this custom "baby extreme" file. :evil:

 

[vegasGTI]

Yes the rs4 fpr was in my file description for the H. O. when getting my ko4 file.last week and it didnt used to be. Which means they tuned for it and you can feel the difference up top the car keeps pulling more.

 

[ROH ECHT]

Mine was put in without removing the intake mani and it was a bit of a PITA. I put it in when switching to GIAC K04 hi-output remap from awe/giac K04 remap and all is well, but it was before as well. No problems to date with any of my mods with performance.

 

[Stranded in Daytona]

Sorry to bump an old thread, but would this install be any easier without the front clip on the car?

Say like when you are installing a FMIC?

 

[josein06gli]

...

 

[gti2slow]

Bump, forgot to install the RS4 PRV and dont want to pull the manifold again. Is this doable if you have normal man sized hands. Seems like there is no space at all in there.

 

[DC Dubber]

I was able to install mine without removing the manifold. It's tedious but it can be done. It can be a bit tight depending on the size of your hands. You'll need a few crows foot extensions for the job. Removal was easy took about 15 Minutes. Getting the new one in was the tough part. After dropping the PRV a few times I finally managed to get it in there. On a scale of 1-10 I'd say the job is a 6.