Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 34)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 27
 The mounting angle of the sensor should be tilted a minimum of 10 o
to the horizontal tip of the
sensor. The tip of the sensor must be tilted down. See the diagram below. The optimum
sensor angle is 90
o
.
 Make sure sensor cabling is routed and secured away from the exhaust system.
Stainless steel mounting bungs are also available for turbocharged applications.
Drill a 7/8” – 15/16” hole in the exhaust pipe. Weld a WBO2 sensor-mounting bung into the exhaust
pipe. The mounting bung was manufactured with a lip to help locate it prior to welding it to the
exhaust pipe. The entire circumference of the mounting bung must be welded and free of exhaust
leaks! Exhaust leaks around the bung will affect sensor readings! Carbon and stainless steel
bungs are available from BigStuff3.
Once the sensor-mounting bung is welded into place, thread the sensor into the
bung. Installation torque is about 10 – 15 ft/lbs. Connect the oxygen sensor 6-
way connector (with gold plated terminals) to the main wire harness.
7. ECU Installation
The ECU must be installed in the passenger compartment! The ECU has
four ¼-20 x 5/16 x ½” threaded isolation grommets threaded into the
bottom of the housing. To avoid the potential of severely damaging the
ECU,
connect the head connectors to the ECU only after the battery
connections are made .
Note: If the factory installed isolation grommets are not used to mount
the ECU, the bolts used must not extend beyond the ¼” factory installed depth. Using bolts or
threaded rods that are longer than ¼”
will contact and damage the ECU, and void the warranty!
The isolators are not used for any type of electrical grounding.
10 o angle, minimum
Oxygen Sensor Oxygen sensor mounting
bung (entire circumference
needs to be welded)
Exhaust Pipe
The optimal
angle is
completely
vertical or 90
o
This side (with the mounting lip) goes into the
exhaust pipe to locate it prior to being welded
Header 1
Header 2