BOV Plumbing
 

Hi all, i have a greddy kit running 5psi at the TB. it has a ebay knock off BOV, i think its designed after the greddy also. there are 2 vacuum nipples on it one was hooked up when i bought the car and the other was open. what is it supposed to be hooked to. diagrams are awesome if you know of any.

I've got mine hooked up to the top nipple:

https://www.miataturbo.net/attachmen...ine=1313531673

I hooked it up the wrong way before and got massive compressor surge, so I'm pretty sure it's correct now.

Bottom can be left open or plumbed to a boost only source. I currently have nipple on my compressor housing plumbed to the bottom nipple of my GReddy Type-S. It reacts quicker with it plumbed this way.

https://www.miataturbo.net/attachmen...ine=1313532972
im a :noob: to the turbo world, here is my bov. so as i understand it one goes to vacuum line and the other goes to the turbo.

The one in the top (the purple part) needs to be plumbed someplace in the intake manifold AFTER the throttle body (so it sees vacuum when you close the throttle). The other one can either be left open to atmosphere, or plumbed somewhere in your intercooler piping BEFORE the throttle body (so it will only ever see boost or very very little vacuum when you're off the throttle).
It allows the valve to act more quickly.