The one sensor is in charge of feedback for the entire fuel system, it needs to see the full amount of exhuast but not because of metering or trim, (which an O2 sensor actually does) but because of balance. If one side develops an injector leaking and the sensor is only in the other side it will not set a rich code and may cause some cat converter damage
Now...without a catalytic converter the point is moot.BUT performance may suffer and a lean condition (such as a plugged injector)could cause damage to the engine and no early warning would be sent VIA the engine light.
It would be Ideal to use an x pipe or an H pipe, and place the sensor just downstream of the crossover so that exhaust pulses from both sides of the engine cross over the sensor. If you have a single wire sensor it needs to be close to the engine in the exhaust stream. It needs to be hot to work properly, exhuast heat performs the task. If you have a 3 or 4 wire sensor placement is not uite as critical as the extra wires are for a heater built into the sensor so it works sooner and stays more stable through the entire operating range of the engine.
So in short it would probably be OK having the sensor in one bank only but it would be a better idea to have it in the downstream just after the crossover, for peace of mind if nothing else.
Fact is stranger than Fiction
Last edited by LATECH; 09-12-2012 at 07:42 PM.