Woolich Racing offers Zeitronix oxygen (O2) sensors and controllers for measuring Air:Fuel Ratio (AFR) with the Log Box communication interfaces. The Zeitronix sensors measure the amount of oxygen in the exhaust gas coming out of the engine which is used to calculate the AFR. The signal from the O2 sensor is modified by the Zeitronix controller which generates a voltage which is proportional to the amount of oxygen.
A specific quantity of fuel will require a specific amount of air (oxygen) to combust completely, so more oxygen in the exhaust gas means a higher AFR was used prior to combustion.
There are currently two different versions of the Zeitronix Zt-3 O2 controllers as well as several different sensors. Each sensor is only compatible with a specific controller, if something goes wrong with your controller or sensor we will need to know which version you have in order to support you.
To determine what controller you have you can look at the color of the LED on the Zt-3 when it is powered up. To determine what sensor you have, you can measure the size of the connector and compare with the information below.
LSU 4.9 Zt-3 Controller (typically sold in our Zeitronix kits)
- Green LED visible when unit is powered, and flashes when outputting AFR data.
- Compatible with LSU 4.9 wideband sensors
The LSU 4.9 sensor unit has plug which is approximately 0.9" x 0.6" (22mm x 15mm) as shown below:
LSU 4.2 Zt-3 Controller
- Yellow LED visible when unit is powered
- Compatible with LSU 4.2 wideband sensors
The LSU 4.2 sensor unit has a larger plug which is approximately 1.25" x 0.8" (32mm x 20mm) as shown below:

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