I dont think you can vent it to atmosphere, unless the new one works differently. When the car is idling (pulling full vacuum) the valve is open, so it is like having a huge vacuum leak And yes I did experiment with it and found out the hard way

Simon new- '04 Dodge Dakota 4x4. V8, 5spd FOR SALE Black 98 SVT EO (#2119 of 6535)- SOLD! New project-'88 Ranger 302 swap.