Debate on DV recirculating v's non recirculating DV.

I here all the talk of recirculating dv but surely recirculating the air back before the turbo under pressure just means that the recirculating air pushes the air out the intake tube the wrong way including pressure waves, thus causing delayed spin up due to the change in direction.

Would be interested in anyones thoughts.

on the vag range you best off buying an uprated recirc dv. the recirc valve is there for a reason to keep the system closed loop! yes the standard bosch 1 is crap but an uprated 1 is your best bet

I use atmosperic - better out than in! However, there is probably some truth in your theory but it is more likely to cause a miniscule pressure drop rather than delayed spin up as the exhaust gasses are still driving the impeller. You really wouldn't notice this in performance, well perhaps in the le-mans 24hr where you could lose a second! maybe. I would be more worried about dump valves sticking and bleeding away the boost pressure from the inlet. This is quite common with bailey DV's which can stay open at certain rev's requiring a quick tap on the pedal to unstick em.