Turbo - Please help explain the Recirculation Valve

[bene91]

Hi all,

I have been given a few bits of information (after looking for myself 1st) but they haven't been the same so I want to see what you lot think/explain as well.

Standard turbocharger on a Petrol engine. It has a recirc valve on it, with a connection for a vacuum line.

1. Am I correct in assuming, the 'norm' would be to have a vacuum line from this recirc valve connection to the intake?
2. What would be the effects of having the standard recirc valve in it, but have no line attached to it?
3. What would be the effects of having a recirc blanking kit on it? (and not using a BOV)
4. If I'm wanting the turbo to be around 10-12psi of max boost, if not using a recirc blank, what PSI spring would be best for the recirc and why?

Any help on any of the above would help me.

Thank you !