RS4 Fuel return valve

[CupraK1]

Any one else tried this?

The RS4 valve can cope with up to 150bar of pressure requests

a must for stage 2+ cars with flat spots at 5k where more fuel is requested

[Hendrik]

AFAIK, the RS4 valve has a limit of 136 bar...

[CupraK1]

Quote, originally posted by Hendrik »

AFAIK, the RS4 valve has a limit of 136 bar...

The RS4 fuel return valve replaces the OEM one. The OEM one opens a return valve at 130bar and allows pressure to drop to as low as 127bar before building pressure back up again. On the RS4 valve the pressure is designed to go to 136 bar and then the return valve opens, but closes again at 130bar. All depending on requested rail pressure.

REVO Stage 2+ requests 130bar and then higher in the rev range 132.5bar around the mythical 5krpm mark.

Before I had the valve, my actual rail pressure never managed to meet requested pressure apart from the point where I let off WOT. This POSSIBLY could point to a performance dip if the ECU detects the inability to meet requested pressure and then back off the power.

[staulkor]

How difficult is it to get to the valve? I was thinking about upgrading as I am a few bar lower than requested in upper RPM.

[CoNGLoMeRaTeGTi]

Quote, originally posted by staulkor »

How difficult is it to get to the valve? I was thinking about upgrading as I am a few bar lower than requested in upper RPM.

ECS and world impex or whatever it's called carries it. It's 100 bucks shipped.

I'm running one. I get well over the Revo requested fuel pressure amount. My LPFP duty % valve went down drastically.

[CoNGLoMeRaTeGTi]

PN is 079130757

[LEWXCORE]

How come this hasn't come up before? You think this will help flow a little more to the RS4's on a LPFP maxed out big turbo seup.

[Arin@APR]

Quote »

The RS4 valve can cope with up to 150bar of pressure requests

As others have said, it's actually 136bar, not 150bar.

[CoNGLoMeRaTeGTi]

Putting this on will give an extra 73ish psi. My math isn't the greatest off the top of my head. Lol.

Running a 630cc injector at 3 bar is completely different at 4bar.

I'll be getting on the dyno shortly to see if it has effected my power curve. The car feels much more responsive with it.

[LEWXCORE]

so our fuel rail is for 130bar, the rs4 is for 136bar, doesn't seem like it should make a huge difference... other options anyone? arin?

[jonnyc23]

An extra 6 bar of fuel pressure is pretty significant I would say.. Wish I had tried this, lots of people are reporting good things with this mod..

[CoNGLoMeRaTeGTi]

Quote, originally posted by LEWXCORE »

so our fuel rail is for 130bar, the rs4 is for 136bar, doesn't seem like it should make a huge difference... other options anyone? arin?

most folks average 120-127bar on the stock valve. Even if the request is 129.99.

With the rs4 valve Im well over the requsted amount

[CoNGLoMeRaTeGTi]

Quote, originally posted by Arin@APR »

As others have said, it's actually 136bar, not 150bar.

huge thumbs up to APR for making an awesome HPFP.

A friend of mine and I did the same RS4 valve upgrade and he seized his HPFP at 132bar. He unfortunately was not running the APR unit. However, one is on the way. .

[Arin@APR]

Quote, originally posted by LEWXCORE »

so our fuel rail is for 130bar, the rs4 is for 136bar, doesn't seem like it should make a huge difference... other options anyone? arin?

It depends how far you are pushing everything but I think you may find you'll run out of high pressure fueling, essentially maxing out the hpfp. Adding the 136 may not really help as you may not even be able to achieve above 130 depending on how much fuel you are using.

[CupraK1]

well i only need this as the revo stage 2+ file with my autotech HPFP feels like its holding back a lot at about 5.2k then it picks back up again... (no revo bashing pls)

[ndifadvokit]

i'd like to see more info on this especially from people who are actually running the valve. Any downsides to running the valve? Increased stress on HPFP? Are there noticeable gains to be had if you aren't currently experiencing problems? Are people with problems masking their real problem with this? This seems to be a mod that hasn't really been talked about much when it appears to have a plausible worthwhile advantage.

[CupraK1]

There is also a by-product of fitting the RS4 valve and this is that it alters the pressure in the in-tank low pressure pump. The OEM low pressure fuel pump before the valve was fitted started off at 4.5bar pressure, but gradually dropped to around 3.4bar pressure at higher revs when WOT. After the RS4 valve was fitted the in-tank pressure stabilised at between 4.1-3.9 bar across the entire run whilst WOT. This too could point to where you would get a drop in power around 5krpm as the in-tank low pressure fuel pump drops below 3.5bar around those revs, which is outside normal parameters and MAY cause fuel cuts or the ECU to back off the power.

The RS4 valve can cope with up to 150bar of pressure requests (GIAC Extreme Beta file testing), which is the limit of the high pressure fuel pumps anyway.

I must stress that all this is from readings taken from live logging on my car, but the diagnosis is subjective although compelling in the logic.

The valve costs under £50, but is a pig to fit as it is located under the intake manifold and at an awkward angle to reach with spanners. I for one think it was worth it, just for peace of mind that it eliminated another variable from the "power dip syndrome"

[ndifadvokit]

Were you able to change the valve out without removing the intake manifold? I might have to run some logs to see what kind of values i'm getting right now and then just try this valve to see what happens afterwards. I'm not really convinced yet that i NEED it or would benefit from it though.

[CoNGLoMeRaTeGTi]

Quote, originally posted by ndifadvokit »

Were you able to change the valve out without removing the intake manifold? I might have to run some logs to see what kind of values i'm getting right now and then just try this valve to see what happens afterwards. I'm not really convinced yet that i NEED it or would benefit from it though.

Pretty damn hard to remove it when the intake manifold is on the block. It's soooooo much easier with the manifold off.

[ndifadvokit]

Quote, originally posted by CoNGLoMeRaTeGTi »

Pretty damn hard to remove it when the intake manifold is on the block. It's soooooo much easier with the manifold off.

When you say it's hard to do it do you mean it's in a tough place but if you can manage to reach it it comes out easy or do you mean it will take me longer to change it that way than remove the whole manifold? I personally thought it was pretty easy to remove my intake manifold but it wasn't a 30 min job. How are you liking your rs4 valve? Would you recommend it?

[Arin@APR]

Quote, originally posted by CupraK1 »

The RS4 valve can cope with up to 150bar of pressure requests

I know people were going nuts over stage 2+ requesting 130 bar instead of 110 bar with concerns for the cam shaft. Now we are discussing 150 bar?

Discuss...

[CoNGLoMeRaTeGTi]

It's a special order part on ECS as well as world impex. It'll take about a week or two to get.

I'll take a pic of where it's on the manifold. I have my car in pieces as of last night. Lol

[CoNGLoMeRaTeGTi]

with the mani on.

[CoNGLoMeRaTeGTi]

mani off

[Runin2Rich4FSi]

this is interesting.... my car has had a slight issue with fueling as I go through the gears.. I wonder if this would help. Changing the valve on the pump, changing fuel filter, and swapping lpfps have done nothing. First I need to run more logs.

[CoNGLoMeRaTeGTi]

Quote, originally posted by Runin2Rich4FSi »

this is interesting.... my car has had a slight issue with fueling as I go through the gears.. I wonder if this would help. Changing the valve on the pump, changing fuel filter, and swapping lpfps have done nothing. First I need to run more logs.

i had the same issues.

arin schooled me to the possible rail valve issue.

i remember him telling me that the A4s were having the same issues. since he mentioned A4s i completely ignored it. but i then found a very old thread where he posted up something about it and i decided to take the dive. car has been running like a savage since. i am now able to break third loose.

this valve is really for individuals that are running software that require 127+ bar. otherwise the regular valve works for software that requests 122-125(uni).

[Runin2Rich4FSi]

thanks, my stage 3 sometimes has the power in the 3rd to let loose, but more times than not... I am a little flat on power. I will order this tomorrow and give it a shot. I will report back in a few weeks or less.

[yvrnycracer]

can someone toss out the PN for the rs4 fuel rail pressure valve?

would be interested in seeing some results here...

[Runin2Rich4FSi]

Quote, originally posted by CoNGLoMeRaTeGTi »

PN is 079130757

[rracerguy717]

Quote, originally posted by yvrnycracer »

can someone toss out the PN for the rs4 fuel rail pressure valve? would be interested in seeing some results here...

Quote, originally posted by CoNGLoMeRaTeGTi »

PN is 079130757

[Runin2Rich4FSi]

Quote, originally posted by yvrnycracer »

can someone toss out the PN for the rs4 fuel rail pressure valve? would be interested in seeing some results here...

sent pm.

[yvrnycracer]

i think i am totally a dumb ass

but am i talking about one in the same here?

[rracerguy717]

Quote, originally posted by Runin2Rich4FSi »

this is interesting.... my car has had a slight issue with fueling as I go through the gears.. I wonder if this would help. Changing the valve on the pump, changing fuel filter, and swapping lpfps have done nothing. First I need to run more logs.

Rich Funny thing is im on a stock intank pump and i have no issues maybe your APR upgraded intake pump is spiking above and popping your stock valve open hence the fuel pressure drop ? Bob.G

[Runin2Rich4FSi]

I swapped out my APR pump and went back to the stock one.

[CoNGLoMeRaTeGTi]

Quote, originally posted by yvrnycracer »

i think i am totally a dumb ass but am i talking about one in the same here?

http://www.worldimpex.com/part....html

doesn't get easier than this