AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 216)

Page 216 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Advanced Tuning
Boost Control
The AEM EMS has a very comprehensive and flexible boost control function. Using a pulse
width actuated solenoid, boost can be controlled by vehicle speed, throttle position against rpm,
and a switch input for low and high settings. The first step in creating a new setup is determining
what frequency the solenoid needs to be operated. This information is typically provided by the
manufacturer of the part. If you are using a plug n' play with a factory boost control solenoid, this
comes preconfigured by AEM.
The PWM output pin needs to be determined when installing a boost solenoid. Refer to the
Application Notes for the pinouts of the specific EMS used. This information can also be found
on the AEM EMS forum (www.aempower.com). There are two wire connections for a boost
solenoid and there is no polarity. One wire connects to 12 volt switched power and the other will
connect to the PWM output on the EMS.
The following example setup shows how to configure the GPIO7 output on an EMS-4 for use in
the Boost Control function:
Boost WG Duty Max – Defines maximum duty cycle for boost control output.
Boost WG Duty Min – Defines minimum duty cycle for boost control output
Boost WG Output 1 – Defines the output pin to be used for the boost control function, in this
case GPIO7. Remember that on EMS-4 applications, only outputs GPIO5 through GPIO8 can
be used for PWM/Duty cycle control outputs.
GPIO7 40/64Mhz – Scaling function to increase frequency range. Internal AEM use only.
Default setting is OFF.
Boost WG Frequency – Defines the period in microseconds for this output.
1 microsecond = 0.000001 seconds or 1 x 10 -6 seconds
33000 x 1 x 10 -6 seconds = 0.033 seconds
Frequency = 1 / Period so: