Sandwich type adapter that fits between the existing electrical solenoid and the turbo charger housing.
On the 2.0 FSiT TFSi turbo, built into the turbocharger housing, is a
bypass facility. This allows charge air to be recirculated around the turbo charger from the boost side back to the intake side.
This re-circulation path is opened and closed by means of an electrical connection from the engine management to a solenoid that is mounted on the turbocharger housing.
As you accelerate , the turbo charger vanes are spinning and boost pressure is increased,
literally blowing into the engine cylinders.
While you change to a higher gear the throttle valve to the engine closes. The problem here is that during this process the turbo is still spinning and the boost pressure that it is producing has no where to go.
(This is a bit like putting you hand over a hair dryer so the air cannot get out)
What happens at this point is the turbo starts to stall, the spinning vanes slow down and the boost pressure drops.
When the throttle valve opens again the turbo has lost its momentum,
boost pressure and there is a pause or a "Lag" before the engine is producing the required power once again.
To combat this loss of power and stress on the turbo, a re-circulation or diverter valve is used.
When the throttle valve closes, the engine management opens the re-circulation route around the turbo.
This gives the charge air an alternative route and allows the turbocharger to keep spinning so that when you accelerate again there is no "lag" or waiting period.
This system works well and is adopted by nearly all vehicle manufacturers on turbo charged petrol engine applications.
The only downside to this system is that a turbo chargers produce heat.
By recirculating the hot air back into the intake side of a turbo the temperatures increase.
This is where the Blow Off or Dump valve plays its part.
By expelling the charge air to atmosphere rather than recirculating it, you do not increase the intake air temperature but you do allow the turbo to keep spinning.
The side effect which is unacceptable to most vehicle manufacturers is the noise of the valve expelling the air.
By fitting the adapter between the existing solenoid and the turbo housing (this involves removing only 3 bolts) the air is re-directed to atmosphere rather than recirculated.

Fits:
VW and Audi 2.0L FSI and TSI engines with the Bosch ME9 engine management systems.
Volkswagen 2.0T / Audi TT & A3

NOT ALL VEHICLE ARE LISTED ON THIS LIST JUST A FEW.

VW Golf MK5 2.0 FSI Turbo - 2005 - 2008
VW Golf MK6 2.0 TSI Turbo - 2008 - Present
VW Bora / Jetta 2.0 FSI Turbo - 2005 - 2010
Audi A3 8P 2.0 FSI Turbo - 2003 - Present
Audi A4 B7 2.0 FSI Turbo - 2005 - 2008
Audi A4 B8 2.0 TSI Turbo - 2008 - Present
Audi TT 8J 2.0 FSI Turbo - 2006 - Present
Seat Leon MK2 2.0 FSI Turbo - 2005 - Present
Seat Leon Cupra 2.0 FSI Turbo - 2006 - Present
Seat Altea 2.0 FSI Turbo - 2004 - Present
Seat Toledo 2.0 FSI Turbo - 2004 - 2009
Skoda Octavia 2.0 FSI Turbo VRS MK2 1Z - 2004 - Present
VW Passat 2.0 FSI Turbo B6 B7 - 2005 - Present
Audi A6 C6 - 2004 - 2011
VW Tiguan 5N - 2007 - 2008
VW CC TSI 2009 - Present
VW CC GOLF6 GTI R20 SCIROCCO Audi,etc