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Oh and my car ate up a Focus RS at the 'Ring and a GGR RS Focus at Spa![]()
thanks for the info dude
well you dont have to do to much convincing the more i have looked into them the more i likejust need to go and try one now me thinks,
Hurdy,
Tell us more about the rs4 fuel return. Im wondering if it has the potential to cure the flat spot people have been suffering from.
Hurdy,
Tell us more about the rs4 fuel return. Im wondering if it has the potential to cure the flat spot people have been suffering from.
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.
There is no definitive proof on this, but since I had the RS4 valve fitted the dip in power has disappeared, although this could also point towards the Forge actuator as this was set-up at the same time as the valve was fitted.
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"
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any chance of a part number. Will get my mate to fit this onto mine.
Cheers
Thats whats getting done on mine next week. I did ask if it was worth fitting an uprated actuator also, but I am not sure that it is based on what I have read/heard. John - did you uprate your OEM in tank pump yet?
yeah i am getting this part fitted in 3 weeks when i get the extreme map. hoping it makes a differance, i havent got a flatspot but it will mean the pump i have on now isnt working to nearly it 100% capacity/ability. do you know if anyone is running the extreme file yet hurdy and what numbers/gains they are claiming? i was going to go for the uprated actuator but it isnt an easy install to tie in with the GIAC software as it isnt tunable to the average user. unless GIAC bring out a new map that is set up to run with a non OEM actuator it is a no go for me, i doubt that GIAC will do this anyway!
I got this part number off a guy on the US site - 079 130 757 (pressure regulating valve)
The self study shows the part on page 27.
http://www.jlosee.com/images/RS4/PDF/Audi.ssp.921603.pdf
If you want a spin in mine sometime, you know I'm local![]()