GFB Mach 2 T9120 conversion kit to atmospheric vent (20 mm plug)

Conversion kit for converting the Mach 2 valve from recirculating discharge to atmospheric venting.

The kit includes a trumpet-shaped adapter, a stiffer spring and a plug for a 20 mm hose.

For the Mach 2 valve to vent to the atmosphere, the piston must remain closed at idle and the recirculation hose must be plugged. The conversion kit for atmospheric venting 5920 includes a plug for a 20 mm hose, which is used to close the recirculation hose, a trumpet-shaped adapter to replace the hose outlet on the Mach 2 valve, and a stiffer spring (part number 6115). The trumpet-shaped adapter is not essential for operation, but it produces a louder sound.

The Mach 2 valve is supplied with a softer spring (part number 6116), which is suitable for recirculating discharge or vehicles with an idle vacuum of 18 inHg or less. If the piston remains closed at idle with the existing spring, the spring does not need to be replaced. However, if the piston remains partially open at idle even with the spring preload set to maximum, the stiffer spring from this kit must be installed to prevent the engine from stalling or backfiring.