Camo- he DOES HAVE a wideband o2 sensor "prong" in the exhaust as part of his dashboss build. Dashboss allows for external sensors like boost and EGT and Wideband O2 to be displayed and datalogged alongside the internal PID set that can be gathered from the ODB2 port datastream.
I'd say to compare, do one test loop of all sorts of driving, idle, casual, a few good pulls, maybe a wot or two, followed by some slower stuff and end it. Start with the ipad for this first datalog.
Then set up the iphone with the same 12 datapoints in the same locations (for ease of comparison) and repeat the same test loop. Of course, car will be slightly hotter second time around, as well as if you run into traffic or whatnot, there may be some variance here and there, but should be mainly negligable.
Now from each device, go into the log viewer and email yourself each CSV file, and then from a computer, open up excel and view the data side by side. Again, some variance is expected due to different conditions between runs, but if you did about the same each time, it will be good enough to compare.
Unless you chose a different PID to monitor (for example, absolute throttle position is quite different than normalized throttle position) the data should be the same. The dashboss is still transmitting the car's ECM metrics, and it's also still reading wideband values during all the different parts of your test loop similarly. Idle doesn't really count, since there's no load on the engine. Fuel trims, afr, and all that are more useful when you're driving, as that's more 'real world experience' of the car.
It can help to have the ipad and iphone side by side when setting up your 12 values that you will be monitoring, if you pick the wrong one for one of the cells, then those numbers won't match up at all between them, which could easily explain why you have disjoint data.
--zepcom
