Sticky Air By–Pass Valve

      Air By–Pass Valve

      Air By–Pass Valve

      Even though the engine switches from turbocharging to a deceleration state, turbocharging continues briefly due to
      the inertia of the turbocharger turbine, so the pressure between the turbocharger and the throttle valve increases.
      Because the distance between the turbocharger and the throttle valve is longer in the 3S–GTE engine of the MR2 than
      in the 1990 model Celica, iintake air noise is produced. The air by–pass valve is installed to release this pressure and
      reduce the intake air noise.


      Construction


      The air by–pass valve is opened and closed by the vacuum applied by the vacuum hose from the intake air chamber. This vacuum hose divides, one side leading to chamber A and the other leading to chamber B. However, the hose leading to chamber B has a VTV (Vacuum Transmitting Valve) installed in it to delay application of the vacuum.



      Operation


      When the engine changes from turbocharging to deceleration, a strong vacuum is applied by the vacuum hose, by the vacuum is not applied right away to the chamber linked to the VTV. Accordingly, the diaphragm is pulled toward
      chamber A where the vacuum is strong, thus pulling open the air by–pass valve. As a result, the compressed air between the turbocharger and throttle valve flows through the air by–pass valve to the upper flow side of the turbocharger.