I couldn't find this issue on S2KI, but there are plenty of other forums (not s2000 related) saying a recirculated bov is a MUST. I'm almost done completing my Greddy Turbo kit. I also just picked up a Greddy RZ BOV and was wondering if it was necassary to recirculate it. I don't have huge goals and will most likely be tuning with Greddy EMU. How will the car run with open atmosphere set up?

I've googled quite a few picture of people with the greddy turbo kit installed and none of the BOV's seem to be recirculated.

 

Recirculation is a must on a vehicle that uses a MAF (Mass Air Flow) sensor, as the air in the charge pipe is already accounted for. On our car it is not necessary as we use a MAP (Manifold Absolute Pressure) sensor on the intake manifold.

That said, I recirculated my BOV for two reasons. One, in Australia it is illegal for air to leave the system after it has passed through the filter except back out through the filter (an open BOV will get you defected meaning you get a fine and are ordered to fix and have inspected), and two, I am hoping to cut down the ricey 'PSSSSSSFFFFFFSSSSHHHHHHH' noise. I'm all growed up.

 

Exactly. I would also add that the purpose of a BOV is to release excess pressure from the system when you let off the gas. Without a BOV, the air will try to force its way back through the compressor. This is called surge and can damage the turbo.

 

Oh. I see I see. Good information, thanks.