Mate.
This **** has been covered three time THIS WEEK and as I am sure you are aware it is only 10AM Tuessay morning.
And no I don't ask questions, I research, understand and then make my decision. Once my decision is made I help inform others on my experience.
I'm all for helping people and sharing knowledge, but this really is a daily thing which is always answered in exactly the same way, and then followed up by somebody who doesn't really know contradicting what has been said, then someone who hasn't got a clue saying it worked fine on theirs.
Google, search, basic thought process behind how a DV works...All lead to the same answer.
The purpose of a DV in its most simple form is to release pressure to save compressor stall, releasing to atmosphere is one way. A better way to release the pressure would be to re-use that charge to aid the turbo on re-application of the throttle.
It really is that basic, and if you don't understand those basic principles of forced induction then you have no place playing with the set up and should be taking it to a specialist to do the work for you.
I know I sound like a total vagina, but it has to he said.
P.S, I ran an atmospheric valve for two thousand miles+, noticed no running faults as such (mapped ME3 AGU) however my fueling was miles out on over run and the car was considerably healthier when I went back to my Forge 007p which I had been running forever.
I have had a Bailey DV30, a Bailey DV26, two Forge 007P's, I have tried a Split R, I have tried three revisions of the 710n.
And now that I have got the most powerful K03s A3 in this country, guess what DV I run? Uhhuh...Standard 710N bought from TPS.
Stick with the OE valve, fit a cone filter, up the boost. My car is easily as loud as an atmospheric valve when it drops 22psi if that is what you want, and it drives better for it.