Narrowband to AEM Infinity

The Infinity uses some specially designed circuitry (including a Bosch chip) to interface with the LSU4.2 sensor. Heater duty cycle is controlled using closed-loop feedback, and many of the sensor wires are checked for simple diagnostic errors like disconnects or shorts to power/ground. Lambda feedback gets disabled if diagnostic errors are detected or if something is preventing the sensor from warming up to operating temperature. There are a few problems that won't be detected such as air leaks interfering with measured O2 content, or a fouled sensor, or some instances where the ceramic element is cracked but the temperature somehow registers within the normal warmed up range. You can limit the amount of wideband feedback allowed if you don't completely trust the sensor, for instance +10% if lean conditions are detected but only -3% if rich conditions are detected.

I'm not familiar with how the S2000's 4-wire OEM sensors work, but it's unlikely the Infinity would be able to replicate the OEM ECU's heater control for the generic low-side outputs, and I wouldn't trust a heated O2 sensor's data without accurate heater control. We didn't do any work to support narrowband O2 signals, we couldn't see how they would be useful for the conditions most racecars operate in. I'd spend my time and money adding sensors for things like fuel pressure, oil pressure and oil temperature.

That said, I'm interested to hear how this turns out if you try it.