Diverter Valves

Diverter Valves open on gear change when the throttle body is closed as you lift off the accelerator,
they stop the turbo trying to force airflow into a closed off pipe by opening another path for the air to recirculate.

They help throttle response by minimising the backpressure on the turbo allowing it to keep spooling and be back on flow when you reapply the throttle.

The standard supplied Bosch one is cheap and nasty plastic moulded
thing with a diaphragm.
In my opinion diaphragms are for girls.....a man needs a good piston valve! :o)

So on recommendation I have a DV006 Forge dump valve in black.
I am now running a Forge 007p which is superb.

Does it feel any better?, yes, gear changes and throttle response are much improved.