O2 Sensor Location?

Tim Collins

We have designed and ordered all the material to fabricate the headers for the Coyote. My question is…how sensitive is the O2 sensor signal, relative to the adjacent bend? For wire routing I would really like to position them after the collector, but we have a bend an inch beyond the bung. The backup pan is to weld them in the straighter section of the “H” pipe.

The header tubes are 1.75” OD with .065 wall, 304 stainless. The mufflers are Burns 2-stage quiet, 4.5” diameter with 2.5” inlet/outlet.
O2 sensor Loc.JPG

Bundle dwg.JPG

headers LF.JPG

headers rear.JPG

header LR.JPG


Mine are just after the collector, as your prefered location. Then again, I dont have any other option, since it goes straight into a muffler after that.
My understanding is that your second location would be better;
1) The gasses from each cylinders are mixed better to prevent unsteady gas composition to be measured by the sensor. (from each cylinder pulse)
2) The risk of moisture damaging the sensor during engine start up is lower on the second location. I've had several wide-band sensors fail due to improper heating up (only heat up when engine is running, not on key-on!), and also incorrect location.

If you really want to stick to location 1, I would suggest you move the bung up slightly. So not at 9-oclock, but rather 10 or 10:30
This really protects the sensor from thermal shock due to water droplets hitting a smoking hot ceramic element in the sensor.
Plan a is better ,plan b you may get some feed back of mixtures through the cross over pipe on plan B.
Your sensors will need heaters as they will go cold on A and B