AEM 30-71XX Infinity Stand-Alone Programmable Engine Mangement System Full Manual - Manual (Page 203)

Tuning Guide 197
© 2014 AEM Performance Electronics
KnockNoiseFloor6 Table
Units: Voltage vs Engine Speed
Description: The KnockNoiseFloor6 Table sets an RPM dependant threshold to filter out
background noise from cylinder 6. Setting up this table is key to the success of this function.
Whenever the knock sensor voltage input exceeds this table's voltage value, it is considered to
be detonation. The difference between the detonation signal and this threshold value determines
the severity of the knock.
Tuning with Knock Sensor(s)
To set up the knock sensor control, first identify which cylinders correspond to each knock sensor
input. It must be understood that knock sensors can pickup a lot of noise depending on the type
of sensor and engine setup. The only way the Infinity can determine when actual detonation
occurs is by calibrating the knock sensor being used. The following is an ideal way to set up the
KnockNoiseFloor tables. For this test, use high octane quality-grade fuel.
Get the vehicle on a dynamometer to perform a few 4th and 5th gear power pull sweeps.
Temporarily add 10–15% more fuel in the VE Table.
Retard 2–4 degrees of ignition timing in the BaseIgnMap calibration file.
Start the logger, Log | Start Recording.
At a very low engine speed in 4th gear, such as 1500RPM, depress the throttle
completely to the floor (WOT).
Monitor Lambda1 (or 2) and confirm a safe rich mixture.
If turbocharged, monitor MAP closely as the retarded ignition timing will naturally increase
boost pressure.
If wired and plumbed in, monitor the EGT sensor reading as the retarded ignition timing
will increase exhaust temperatures.
Stop the logger, Log | Stop Recording.
Perform the same test in 5th gear.
For every engine speed breakpoint in the KnockNoiseFloor tables, note the
KnockSense channel's data. This is mechanical noise in the engine that is near the
same frequency as knock but is not real knock.
Draw an imaginary line about 10–25% above these values for every KnockNoiseFloor
table breakpoint. It should start off very low and increase with RPM.
Everything below these points will be considered normal engine noise. Everything above these
data points will be considered true detonation. When actual voltage values breach these points,
knock control will be enabled. So now we need to define what exactly the Infinity should do when
it sees knock.