AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 232)

Page 232 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Add Fuel due to Knock
The Knock %Rich/Volt will add a percentage of fuel per volt above the specified threshold.
The maximum that the EMS can add is set by Knock Fuel Add Max.
The EMS will return the fuel back to normal based on Knock Decrease Fuel and the Knock
Restore Rate.
Remove Timing due to Knock
The Knock Retard/Volt value will remove your specified amount of timing per volt above the
threshold.
The maximum value that the EMS can remove from the engine will be set by the Knock Ign Rtd
Max.
The EMS will reduce the amount of spark advance based on Knock Spark Advance and the
Knock Restore Rate.
In order to have both protective measures running, set both of them up in the knock options.
Knock Center Frequency
Knock center frequency is the sound that the sensor is looking to pick up. AEM suggests that
this value not be changed unless you have done special testing to prove that your engine will
emit a frequency other than this during an actual knock event.
Knock Gain
Knock gain is a knock signal filter. It is used to further desensitize a knock sensor. If this value
gets too high, the knock sensor will not respond to knock events because the values will be
filtered out.
Knock Integrator
Knock integrator is the “window” of time that engine noise is averaged. The engine noise and
knock events will be averaged together in this window.
Please use caution when tuning! The idea is not to advance the timing until the engine knocks
and then back the timing off a few degrees. What we want is to protect our engine from poor
fuel quality or high intake temps. We need to give the engine the proper amount of timing to
produce peak cylinder pressure. Advancing past this point will put you closer to the knock
threshold of the engine.