So I was cleaning out my shop today, and I came across a Zeitronix ZT-2 Data Logger I bought about 2 years ago and used to tune my WRX. Its got inputs for engine RPM, boost pressure, EGT, and Air Fuel Ratio. It also has an LCD Display which shows Boost, EGT, AFR, and Lamba.

I did intake, exhaust, and Quadzilla M3 on my truck, and I want to get gauges before I start getting more serious performance mods. I was thinking about hooking this thing up, since it cost me about $600 and I already have it. Question is, would hooking up the Wideband O2 sensor do anything for me? Is there anything to be gleaned from a diesels AFR?

Seems like everyone tunes for EGT's, and no one ever mentions AFR. I understand diesels throttle on fuel, not air, so there must be a pretty wide range of AFR's that come out of that engine.

Any thoughts?