The stock recirc valves
have a low internal spring pressure which allows the valves to be open when vacuum
is less than -1 psi and this permits air to bypass the turbos during idle and low-load
driving conditions (see “how the Recircs work”).
The Goose Honk Killer (GHK) is a kit that will increase the internal spring
pressure of both factory recirc valves and this additional spring pressure will
only allow the Recircs to open under high vacuum conditions. This
is the exact same reason why aftermarket BOVs prevent the Goose Honk and can be
vented direct to the atmosphere... because they are not open under idle/low-load
conditions, allowing un-metered air to flow into the engine.
The Recirc valves were manufactured as sealed-units, because of this it is not
an easy task to increase the internal spring pressure without some way of
gaining access to the inside of the valves. Also an obstacle is the correct
spring pressure that will keep the valve closed yet allow the Recirc to
still function when needed. The GHK takes care of both these issues economically.
By cutting the top of the Recirc’s diaphragm canister off, the perfect
location for the GHK spring is revealed. The GHK machined aluminum cap simply
presses onto the canister with some RTV silicone to seal the unit again and
the valves bolt back into their stock locations. The GHK
converts the Recircs to the best of both worlds, no more annoying Goose to
detract from your driving experience, no obnoxious BOV sound because they
maintain the stock recirculation plumbing, and the valves still work when
needed to vent boost pressure and reduce compressor surge.
1990-1996 NISSAN 300ZX TT (Z32 - VG30DETT - TWIN TURBO, USDM)
1990-1999 NISSAN FAIRLADY Z (Z32 - VG30DETT - TWIN TURBO, JDM)