Haltech F10 User Manual download pdf (Page 79)

Boost Limit

If the manifold p ressure exceeds this limit, the solenoid valve will immediately be set

with a duty cycle value of 5%. This will allow the full manifold pressure to act on the

waste-gate actuator and force the waste-gate 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.

Update Engine Data

This field allows the waste-gate duty cycle to be displayed on the engine data page.

WARN ING:

WE S TRO N GLY R EC O MM END THE US E O F TH E O VER-BO O S T

FUEL CUT FEATURE DESCRIBED IN THE FUEL SET-UP PAGE

INSTRUCTIONS (REFER 3.1.2 FUEL SETUP, 28).

16.2.3 Using the Boost Controller

The F10 has a “Trim Input” that can be used in conjunction with the Haltech

Trim module

for boost control (Refer 13.1.1 Trim Control and Spare A/D, 61).

In normal op eration the F10 uses the app rop riate bar from the active TWG map (map 1 or

map 2) to drive the TWG solenoid. If the trim module is connected and set for “Boost

Control” the duty-cycle used to drive the solenoid will be the multiplication of the TWG map

value and the trim position.

For example:

If the active TWG map value was 60% and the trim module was set to 40% the actual

duty-cycle driving the TWG solenoid will be 24%.

The use of two independent boost maps allows an engine to be set up for maximum boost

conditions, but driven safely at lower boost pressures without the need of re-loading maps.

The boost controller may be used by the driver to match the engine's power output to the

current demand: higher boost pressures for qualifying speeds, lower boost levels for engine

preservation or wet roads.

16.3 Bypass Air Control (BAC) Valve

16.3.1 Description

The BAC is a PWM output allowing you to use a valve to operate Idle Air Control.

Traditionally, Idle Air Control (IAC) motors have been used but require knowledge of either

how many steps they have or experimentally finding the correct operation. BAC valves only

require a period (ms) setting as opposed to the number of steps, min steps in, max steps out,

etc as required with stepp er motors. The period in milliseconds is the operating frequency for

the p articular valve/solenoid. This frequency can be approximated but an accurate value will

help by giving the best response times. Consult factory information on your

particular/solenoid valve if the operating frequency is unknown: a typical value is approx

10ms.

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Haltech F10 User Manual Page 79