David Gentleman wrote:With dumpvalves, its a bit of a myth, that the 'recirculated air is pushed back into the turbo to help it spinning'. Even off boost, it spinning faster than that dumped air could turn it. The reason most factory cars are equipped with a recirc design, is because of the noise, as no OEM company would want cars hissing down the road from the factory.
I think the major advantage (not huge) with recirc is the volume of air thats put back to the intake. Most advantages in intakes are getting a larger volume of air to the intake (i.e. large volume manifolds).
As for the BOV, doesnt it keep the turbo spinning as there's not a huge pressure difference across the turbine?
i.e. after the turbo is high pressure air, which always wants to move back towards the low pressure side. So if the turbine isnt being driven hard by the zorst, the air will start to slow the turbine down?
Once again, i dont think its a massive benefit on the road - day to day driving...