Haltech IG5 - Manual (Page 54)

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Boost Limit
If the manifold pressure exceeds this limit, the solenoid valve will immediately be set
with a duty cycle value of 5%. This will expose the waste gate regulator to the full
manifold pressure and force the wastegate to open. This value should be set slightly
higher than the desired boost pressure as a fail-safe in the event of an over boost
condition.
Primary Map
There are two maps associated with the TWG control function. Both set the duty cycle
of the solenoid against the engine rpm. The base duty cycle value applied to the
solenoid is derived from either the Standard Boost Map, or the Maximum Boost Map.
Toggling this parameter selects the map from which will be derived the base duty
cycle. The state of this flag also affects the way the Boost Controller (if selected)
operates. See Using the Boost Controller below for more information.
Map Programming
Selecting the Maps heading will bring up the primary boost map, as selected by the
Primary Map flag. The boost maps indicate %duty cycle ON time of the solenoid
against the engine speed. A programmable bar exists every 500 rpm. Increasing the
duty cycle bleeds off more air from the manifold, resulting in a higher boost pressure.
Each bar is adjustable from 5% to 95%. Mapping against rpm permits a varying boost
level with engine speed, so the torque curve for the engine may be customised. These
maps should start with all values at 5%. Load the engine at a constant rpm and
observe the resultant boost pressure at that speed. If the boost pressure is lower than
that desired, increase the height of the bar a small amount. Pressing the
♥ ♥ ♥ ♥
key
switched between the Maximum and Minimum Maps.
13.2.3 Using the Boost Controller
The optional Haltech
TM Trim Module may be used as an electronic boost controller if selected
in the TWG function Options menu. The way the boost controller operates depends on the
which Boost map is selected as the primary map.
If the Maximum Boost Map is selected as the primary map, the duty cycle of the solenoid
will be determined by multiplying the base value from the map by the position of the
controller. Fully anti-clockwise, the controller reads 0%, and fully clockwise the controller
reads 100%. Thus if a value of 60 is derived from the Maximum Boost Map, and the
Controller is set to 40%, the solenoid will operate with a duty cycle of 24%.