Nogaro S4

Anybody using these yet? ... still rice???

Nogaro S4

During light throttle lift-offs when cruising, the piston will only lift about 4-6mm, so the majority of the air is recirculated and will not make much noise. However, when you lift off after hard acceleration, two things happen. First, the pressurised (boosted) air must escape the inlet pipes and intercooler, opening the piston fully and giving a loud "whoosh". Once the pressure is evacuated from the inlet system, the turbo will continue to spin, pumping air through the valve.
In the case of an atmosphere venting valve, the volume of air passing through the valve also passes through the car's air-flow meter (if it is equipped with one).

The ECU will still deliver fuel to suit this amount of air, even though it has escaped to the atmosphere. In some cars this can cause problems such as backfiring and poor throttle response. The Hybrid was the first valve on the market to address this problem by recirculating a portion of air to the inlet. Because of the staged outlet design, once the pressure is evacuated from the system, the piston will begin to close, forcing more air through the recirc outlet and further preventing the chance of backfiring. Now with the StealthFX, your control over this process (and the blow-off noise!) is much greater.

Daryl@Tantrumwerks

several of us have run the older hybrids in the past & a few are running the GFB Stealth valves.

raveman7

Use to have em.. now just straight DV's !!!

<img src="http://pictureposter.audiworld.com/28085/bov_install_014.jpg">