Jaizero

As the title says, I am running a Hahn 20g with a Turbosmart Type 5 plumb back bypass valve. Should this valve be open or closed at idle? If I pull the vacuum line off the valve when the car is running, I do not hear the valve slam shut. If I run manifold vacuum to the valve instead of from the bypass valve solenoid, I can hear the valve slam shut. Turbosmart's website states the valve should be open at idle. I'm a little confused as to how it should be operating?

tomj77

iTrader: (2)

if it says open, then it should be open I guess, uses a light spring. it wont hurt the car non, air is coming out so no dirt can get in.

Jaizero

Well that doesn't help haha.. Does yours have vacuum on the line that goes to the bypass valve from the solenoid at idle?

tomj77

iTrader: (2)

I don't have my car together, but from what I can remember from doing bov the first time, no it should not have vacuum at idle if ur using the solenoid. how the solenoid works is at idle and under throttle the solenoid will only let boost though, which will keep pressure on the bov to keep it closed, when u shift, the ecu switches the solenoid to vacuum side and it will open ur bov. if the spring in the bov is to light, there will not be enough air pressure at idle to keep it closed, so the spring will overcome the pressure and ur bov will stay open at idle. my advice, don't use the solenoid at all. just go straight to manifold.

Jaizero

That's the thing, I'm not using a blow off valve. It's a recirculating bypass valve. I'm wondering if it should be open and recirculating at idle. With it connected to the solenoid, the bypass valve is closed at idle which is sending all intake air to the throttle body, and none is being recirculated. It functions normally under boost and opens to recirculate the excess boost pressure when I let off the pedal. I bought the car like this but I've spent the last 6 months fixing what the previous owner f***ed up. I want to make sure everything is functioning as it should before I really start tuning it. Thank you for taking the time to explain how the system works! I've included a picture for clarification. Ignore the vac line routing. It is hooked up in the stock configuration. I was testing out having it connected directly to the manifold.