I noticed this when driving the car yesterday - a very warm, humid day. Instead of a short, sharp hiss it was a quieter, longer whoosh. It's a forge DV and pipe, blanking plate too. The car still boosts and pulls fine and the DV must still be doing it's job as there is no turbo chatter when letting off the throttle. I just don't understand why it would change like this.
New spring needed maybe mate. Forge do a cleaning kit and it includes a new spring I think. I had to do it on mine but mine wasn't opening at all and it sounds like yours isn't closing properly.
The big yellow spring is fine it is the small, black one that is broken and the DV was like you said, not closed properly. I have no replacement yet, how can I run the car without the DV until then? I know you can plug the hole in the T-piece with something the same size but what about the small blue vacuum hose that goes to the top of the valve?
Ive fitted a new idle spring, is this correctly set up? I can't remember if there was a gap there before. From underneath it appears closed.
My dump valve is open at idle speed, is this how it's meant to be? It closes when the throttle is opened and opens again when the throttle is let off. A search on YouTube shows DVs that are closed until the throttle is opened THEN closed.
