Instruction manual

7 - setting the boost pressure
The duty cycle setting controls the peak boost pressure, and is adjustable from 0-100%, where 0 represents the
lowest possible boost pressure your turbo system is capable of running (commonly referred to as “gate pressure”),
and 100 represents the highest. Note however that the controller is very unresponsive to changes when using duty
cycles less than 10% or greater than 90%, and therefore all boost presets are factory set to 10%.
See page 16 for a detailed description of what duty cycle is and how it works.
The duty cycle must be increased carefully and incrementally until you arrive at a setting that results in the target
boost pressure that you want to achieve.
1. Select the boost preset that you want to adjust (see page 6).
2. Tap “MENU” once to navigate to “Duty Cycle” - the screen will scroll “DUtY”, followed by the current duty
cycle setting, then “PEAK”, followed by the current peak boost recorded for that duty cycle setting.
3. Tap the up/down buttons to adjust the duty cycle setting - it is safest to start at 10 so you can see the
minimum boost pressure, and make adjustments from there. NOTE: whenever you make adjustments to
the duty cycle, the “PEAK” boost value will clear to 0.
4. Do NOT exit the menu
5. Drive the car to record the peak boost – you will need to ensure that you perform a full- throttle run,
sweeping through the engine's peak torque RPM in the highest gear possible/practical to ensure the
controller records the true peak boost - you can do this as many times as you like until you’re sure you’ve
recorded the true peak boost. If you exceed the overboost value, the peak value will be cleared back to 0.
6. Adjust the duty cycle accordingly (higher for more boost), then drive the car again (using the same method
as above to ensure consistency) to record the new peak boost.
7. Continue to make adjustments until you achieve your desired peak boost pressure.
8. When done, tap “MENU” to move on to GAIN, or hold “MENU” to exit. In either case, the duty cycle setting
and peak boost will be saved to the boost preset that you are currently in. The G-Force II will use the
stored peak boost as the target, and will use this target boost for the GAIN and SENSITIVITY features. If
you do not record a peak boost, the controller will still work, but GAIN and SENSITIVITY will not be able to
make any closed-loop corrections.
9. Repeat this procedure for any other boost presets you may wish to set up.
NOTES:
?0-10% duty means the solenoid valve is completely off, and 90-100% duty is fully on - to run boost pressures that cannot be
achieved with 0-100% duty cycle, you must physically change the turbo and/or wastegate - it is not possible to achieve boost
pressures outside of this range with the controller alone (or any controller for that matter).
?It is not unusual for duty cycle values of less than 10% to make little change to the boost pressure, because the solenoid
valve response is non-linear. That is why the default duty cycle in all boost presets is 10%. You may find you need to adjust it as
high as 25% before you start to notice an increase in boost pressure - this is completely normal.
?The higher the required duty cycle to achieve your target boost, the harder boost is to control - it is more likely that boost will
taper at high RPM and vary more according to atmospheric conditions with duty cycles in the upper end of the range.
?For the reason above, it may be difficult to run high and low boost pressures that are vastly different from each other, for
example a low boost of 10psi and a high boost of 30psi simply may not be possible with the turbo and wastegate.
STOP
BEFORE adjusting duty cycle, it is HIGHLY recommended that you first set
up the OVERBOOST feature (see page 11 for more information).
OVERBOOST is a “global” setting that will turn off the solenoid if boost
pressure exceeds the overboost setting (regardless of the boost preset
currently being used), which is intended to prevent damage to your engine
if the controller is adjusted incorrectly or accidentally.
The factory default setting is 100kPa (1 bar, 14.5psi).
duty cycle