Edelbrock 3670 User Manual - page 199
Features Available with Pro option only
199
Tips for tuning:
Note: This table should only be adjusted by experienced tuners!
In general, this table should need no adjustment and the calibration will be loaded for
you by the setup wizard based upon your O2 sensor selection. Although the table defines
a band around stoich, as a performance tuner - you generally only have to think about
the rich limit that you want to allow closed loop operation to occur, since performance
engines very seldom are tuned leaner than stoichiometric anyway.
Entering "0" in a cell will disable closed loop operation at that throttle position. The table
above shows the typical values pre loaded for a wideband O2 sensor. A true wideband O2
sensor has the capability of being accurate over a much broader range than factory
switching style sensors. The values in the above table will allow the engine to go closed
loop if the desired AFR is anywhere between about 9.5:1 and 25.0:1 if the sensor is
capable. In a switching sensor at idle, you generally cannot accurately go richer than
14.0:1 or 1.040 equivalence ratio. (Many performance tuners will prevent closed loop
operation at idle with a switching sensor). At higher loads, a switching sensor can
provide accurate feedback at much richer Air/Fuel ratios than it can at idle. for example,
if you wanted to allow the engine to go closed loop at idle with a switching sensor
because your desired air/fuel ratios are calibrated to be 14.4:1 (which is within the
accuracy range for the sensor), you would calculate the equivalence ratio or refer to the
table below to find the equivalence ratio. In this example, the equivalence ratio is 1.020.
To define the band and enter the proper value in the O2 Equiv Ratio Table - simply
subtract 1.0 from the desired value and enter it in the cell at the "0" position (idle
position equals 0% TPS).
In this case, the entered value would be 1.020-1.000=.020 Enter .020 in the table.
Equiv Ratio Lambda
Gasoline
AFR
1.458
0.686
10.08
1.437
0.696
10.23
1.416
0.706
10.38
1.397
0.716
10.53
1.376
0.727
10.69
1.353
0.739
10.86
1.333
0.75
11.03
1.312
0.762
11.2
1.292
0.774
11.38
1.271
0.787
11.57
1.250
0.8
11.76
1.229
0.814
11.96