Sorry I think I've explained it wrong. When I said "drilled a hole" I meant that I plugged the return pipe so the factory bov vents to atmo. I put the chair leg cap on the end of the blow off valve, the part that vents to atmo, and drilled a hole through that. Not the bov itself. Exactly the same as envy-t. The bov is way too loud and sounds crap without the cap on it. The small hole through makes it much quieter. Bufhoon what you're saying sounds right. At idle it is open a little bit but you're right, as soon as you give a little bit of throttle it shuts down. Just wanted to check this was ok. Bov is back to normal anyway now as too ricey for me.