[Tom Goldman]

I started with the sensors in the primary where Racepak recommends them.
After I got the new carb to its best A/F ,I moved them to the collector , about 6" from the merge.
The readings are similar and are ok to just monitor o2 levels,but tuning is better achieved with it in the primary.
With the senser in the collector, the readings while on the throttle stop are meaningless .
There is too much "free air" around the senser at low exhaust velocity,and it always reads the afr as excessivly lean.
The WOT readings are relativly close to those measured in the primary.
Billy , the Racepak Sportsman data recorder was the best bang for the buck I've spent on a part for the racecar.
Way better than my old TAG recorder.