SETTING YOUR PRELOAD
The internal wastegate actuator is designed to have 2mm of preload applied to the rod during installation. Please
ensure that this is set accordingly.
Clevis Type Actuator
For a clevis type actuator, when installing the clevis of the IWG75 Twin Port onto the wastegate valve arm, make sure
that there is 2mm of preload. Then use compressed air - the amount of air pressure applied should be slightly higher
than what the IWG75 spring is rated to, (do not apply air pressure supply higher than 3 bar (40psi) gauge). This is
required to pressurise the IWG75 so that the clevis can be hooked onto the wastegate valve arm easily. Remember to
reinstall the standard R-Clip or circlip to secure the clevis to the wastegate valve arm. Then tighten the rod nut to
secure the clevis onto the rod.
Non-Clevis Type Actuator
For a non-clevis type actuator, the preload is set by adjusting both of the M6 nuts accordingly. The thread on the rod
is M6x1.0 which means that one full turn of the nut equals 1mm change in rod extension, hence 1mm of preload. To
set preload, hand-tighten the preload adjustment nut (nut A) clockwise to hold the wastegate flap shut. Now, use a
10mm spanner to turn nut-A two complete turns in a clockwise direction. The preload is now set to 2 mm. To lock the
preload setting, tighten the preload lock nut (Nut-B) in an anticlockwise direction until it is hand-tight against the
wastegate valve arm. Use a torque wrench to tighten both nuts to 6.5Nm (4.79 ft-lb).
Confirm that preload is set correctly by applying air pressure (from a regulated air pressure supply no higher than 3
bar (40psi) gauge pressure) to the top cap of the IWG, the rod should move without hesitation once the air pressure
applied to the cap of IWG is higher than the spring pressure.
ACHIEVING YOUR TARGET BOOST PRESSURE
There are various factors involved in achieving your target boost pressure including.
-
The size of the spring fitted in your wastegate actuator i.e. the boost pressure achieved by the wastegate actuator
spring only.
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The desired level of boost pressure and the difference between this and your wastegate spring pressure.
-
The size of your turbocharger, wastegate and the resulting exhaust manifold backpressure in your system.
Turbosmart recommends the ideal setup for achieving your target boost pressure is to use the wastegate actuator in
conjunction with a Turbosmart boost controller.
Rod Nut
Wastegate valve
arm
