AEM 30-2340-N 4-Channel Wideband UEGO AFR Controller - For use with Nascar McLaren ECU - Manual (Page 6)

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BACK PRESSURE COMPENSATION (OPTIONAL)
UEGO sensors are extremely sensitive to pressure. Without an EBP kit (30-2064),
UEGO sensors mounted before the turbocharger will give inaccurate AFR readings due
to back pressure. When the EBP kit is installed correctly, the 4 CH UEGO controller will
output accurate AFR readings. UNDER NO CIRCUMSTANCES SHOULD UEGO
SENSORS BE MOUNTED PRE-TURBO WITHOUT USING THE EBP KIT.
When using multiple 4 Channel UEGO controllers on twin turbo or dual bank engines, it
is recommended that an EBP kit is used for each controller as back pressure levels can
vary per bank. When using multiple 4 Channel UEGO controllers on single turbo
engines, such as an inline 6, it is possible to share a single EBP source. To share a
single EBP source between multiple controllers, the green and black EBP wires for each
controller must be tied together as shown in Figures 6 and 7. Use extreme caution
when modifying the harness as improper connections may result in inaccurate AFR
readings. Be sure to cover all connections with moisture resistant heat shrink or
equivalent covering.
Figure 6. EBP sensor connector Figure 7. Cut & Spliced wires
UEGO ANALOG OUTPUT
The analog output from the 4 CH UEGO controller is a linear dc voltage signal that
varies from 0.5 Vdc at 8.5:1 AFR Gasoline (0.58 Lambda) to 4.5Vdc at 18.0:1 AFR
Gasoline (1.22 Lambda). The signal is used for sending information to a data logger or
an engine management system such as the AEM EMS or F/IC. The transfer function
for the output is listed below.
AFR Gasoline = 2.375(V) + 7.3125
For example, if the output is 2.0 Vdc, the AFR is 12.06:1
2.375 * 2.0 + 7.3125 = 12.06