Edelbrock 3670 User Manual - page 196
196
Tips for tuning:
It is recommended only VERY experienced tuners change the values in the Fuel Adapt
Gain table.
Gains too aggressive will cause instability or non-typical values to be adapted
to the CLC map, particularly if an O2 sensor begins to fail. Small gains are strongly
recommended.
The table is ordinated as a function of error between the desired and actual air/fuel
ratios. The cells in the center represent a very low error, thus no CLC map adaptation is
necessary when the fueling is that close. (zeroes in the calibration cells). As the error
increases positively or negatively toward each end of the table, an adapt rate is entered
which represents a percentage of error which will be "adapted out" or applied to the CLC
map every 5 mS. These values should be very small. Note that even if the O2 error is
very large, with the calculations running every 5 mS (.005 of a second) - the error will be
adapted out very quickly.
If you are running a mass airflow sensor, you also have the ability to adapt the VE map
(airflow) while the O2 sensor adapts the CLC map (fuel flow). This can provide a very
accurate base calibration. If you are not running a mass airflow sensor, you can still
achieve a very accurate calibration through the O2 sensor alone. If you are running
Speed/Throttle control mode - you can apply the adaptation in the CLC map to your Base
Fuel Map to bring your open loop fueling pulse width into tune by using the "Apply O2
Adaptation to Base Fuel Map" function under the tools menu. For more information about
closed loop control or adaptive VE using mass airflow, see the Help section on Adaptive
Tuning .
ECT Spark Trim Table (Pro Option Only)
In Speed/Throttle (Alpha-N) mode, Speed/Pressure (MAP-N) mode, or Speed/Density
mode - there is the ability to adjust a global trim for spark advance based upon ECT. This
can be useful if ignition characteristics change greatly with coolant temperature. While
not often needed, the ECT Spark Trim Table can be helpful in providing a global spark
retard for a very hot engine in order to help avoid detonation.