Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 90)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 83
Same screen as above with the window maximized.
51. MAP AE Decay Rate
The third table is MAP AE Decay rate. It is used to determine how quickly to decrease the Positive
dMAP correction value after accelerating (throttle tip-in) the engine at a given coolant temperature.
The ECU decrements the dMAP correction by the MAP AE Decay Rate. A MAP AE Decay Rate of 6
represents a decrease of the dMAP Correction by 6% every crank interrupt until it reaches zero. In
other words, if you input the number 6 into the table, after 1 crank interrupt the dMAP Correction will
decrease 6%. The 6% per interrupt continues until the dMAP correction reaches zero.
The MAP AE Decay rate table’s fixed values (x-axis) represent coolant temperature, which increase
from left to right. The MAP AE Decay rate input values need to increase as coolant temperature
increases. The larger the value in the table, the quicker the fuel is taken out or decayed.
While the engine is running, a “real-time Ellipse” will move within the MAP AE Decay rate table
relative to the current engine Coolant Temperature “operating point”. Use it as a point of reference to
help calibrate the MAP AE Decay rate table.