When I bought my R26 it had an air filter on it which meant I (and everyone else) could hear the recirc valve operating like a loud "here comes a dickhead" alarm. Replacing it with a standard airbox shut it up. I'm now looking at a remap. If I fit an uprated "silent" recirc valve, like the properfekt one, could I fit an air filter and not hear it?
Nope, as soon as you fit an open cone filter you will hear the recirc valve, regardless of what one is fitted. However it's nowhere near as bad as a vent to atmosphere dump valve.
I have the Properfekt one now with a cone filter, but it was about the same with the standard airbox (with the internal airbox foam removed and corner cut off the airbox). If I drive normal I can't really hear it. It's only when the turbo starts to boost and I then come off the throttle quick do I hear the turbo flutter. Definely a lot quiter than an atmospheric dump valve, but noisier than the standard diaphragm recirc valve, but as said, really only when you come off boost quick. Win the cone filter the recirc sound is the same but I now hear a louder suck sound.
You might not need to change the dump valve. Remember, that they operate only when there is enough pressure difference either side of the spring to overcome the ‘pressure rating’ of the spring. In most situations, this is when the throttle butterfly closes as you change gear - the intake manifold side will almost instantaneously go into vacuum, but the inter cooler side will still be seeing boost pressure. As long as the difference between these pressures is greater than the spring rating, the valve will open. So in theory, regardless of boost pressure, a dump valve should only open when the throttle snaps shut, but in reality, if a turbo spools very quickly, or the throttle isn’t either fully open or fully closed and a car is running high boost, it can create an imbalance which will open the dump valve. This is overcome by fitting a stronger spring, but it certainly isn’t a definite that higher boost needs a similarly stiffer spring; it’s more a case of try it and see. I’m not sure what spring rating the standard dump valve is at, but I know I’ve got no detectable issues in a remapped R26 with standard DV and standard intake, and I’ve certainly got pretty much zero DV noise. Sent from my iPhone using Tapatalk
The Properfekt "quiet" recirc valve is noisier than the standard recirc valve? It what sense is it "quiet" then?
Quiet as in when people normally upgrade their stock valve they go with a vent to atmosphere one, not a recirculating one. I replaced a Forge vent to atmosphere one with the Properfekt recirculation valve and the difference in noise is huge, however I have a Ktec induction kit so it's still not quiet like it would be with a stock airbox
With the properfekt recirc valve you hear the flutter when you come off boost quickly. I don't hear this at all with the standard recirc valve. The properfekt valve is quieter than the vent to atmosphere dump valve and you don't get the whoosh sound as the boost pressure is released. There was absolutely nothing wrong with the standard recirc valve I removed to fit the properfekt so could have saved some money and waited till it went wrong. I like the flutter sound though.
