I think innovate has an AFR sensor that can hook into the OT-2 module and allow you to get that reading.

 

I actually have an auxbox from innovate as well. I believe I can hook up a map sensor to it as well as order the wide band controller. I found the voltage chart for the af ratio, but there arent enough points to accurately correlate to a formula. I'm still pretty happy with this so far. Next project may be a carpc and touch screen.

Also, log works for the computer is able to convert readings from whatever to whatever, but the iPhone version will not. I had a very fast and the furious moment yesterday driving around with my laptop heh.

Also looked into volume pressure relations. Apparently, given a constant temperature, volume and pressure are inversely related. Means nothing for my purpose but it was Cool to know. Boyle's Law