[mark houghton]

Originally Posted by JFairman

There is no increase of turbo lag venting the BOV to atmosphere like mentioned by someone thats never done it.

I stand corrected. I was thinking compressor stall if one didn't have a BOV when I wrote that. I believe that's what BOV's are for in general, recirculating or otherwise, to prevent compressor stall. Gotta get rid of that compressed air when the TB slams closed at shifting. If I'm not mistaken, the Porsche engineers went with recirculating more to handle the rich conditions that occur when venting to atmosphere...I'm guessing probably to meet emissions requirements. If a person had no BOV at all, then the stall (besides causing stress on the turbo) would lengthen the time needed to spool back up by some margin.

When I removed my recirc manifold and installed an aftermarket (Chinese) BOV it was build to do either/or...and I chose to plumb it in as a recirc valve. It would be a simple matter (well, nothing's simple) to re-plumb to vent to atmosphere. Perhaps I'll try that some day, maybe get some cool noise and some flames!