The sensor can often physically replace the
existing oxygen sensor, but for proper operation
of the ECU, it is often desirable to provide
another bung for the wideband sensor. We
recommend you place the NTK sensor a little
downstream of the existing sensor, and certainly before the catalytic converter.

"Always mount the sensor 15 degrees or more
to the horizontal (in the 10 to the 2 o’clock position with wires at the top)."

Some tuning shops use an adaptor that holds the oxygen sensor, and this adaptor is then
secured to the end of the vehicle’s tailpipe. This position is not recommended for vehicles with a
catalytic converter as the converter will change the readings you are measuring (that’s the cat’s
main function in life!). For carby vehicles (or non-operational cats on EFI vehicles) this position
may also be a problem as the exhaust gasses can be quite cool after travelling the length of the
car, and the sensors heater may have to work too hard to maintain an operational temperature.
Serious tuning will require a hotter position closer to the manifold.

Vehicles with a turbocharger should position the sensor after the turbo (and before the cat) as
a high exhaust back pressure (as will be found between the manifold and the turbo) has an effect
on the measured AFR and tends to read richer than is actually the case.