T-Riv tranny

[BLACKHAWK38]

PART THROTTLE OPEN WASTE GATE

Originally posted by Turbo Riviera
IMO, the two port is a superior design for your application. It is common to ALL hot air '84-'85 turbo Buicks.

One port sits behind the diaphram in the wastegate and one sits in front of it.

The grainger valve is like what you would find as a pressure regulator on an air compressor. It allows you to balance the pressures in front of and behind the diaphragm thereby controlling boost pressure and the actuator rod's movement.

THE 2 port waste gate actuator is known as a ("part throttle open waste gate") type.

The bottom port recieves VACUUM only and the top port gets vacuum or boost pressure depending on operating conditions.

THIS DESIGN IS USED FOR 2 reasons, one the waste gate puck is constantly being moved and this helps prevent stickng closed,

THe other reason is for fuel economy, the waste gate puck is designed to be open under low throttle light load conditions , this takes the restriction out of the exhaust gases passing through the turbine wheel, resulting in lower system back pressure and better MPG.


REGARDS , Blackhawk 38