I'm bad at posting videos, anyway heres a link of a dude using the app while driving. You can set the app to only pull certain parameters, which in turn makes the app run faster. In my experience it was pretty close to real-time. Maybe a .1-3 second delay.
http://www.youtube.com/watch?v=CNOLA...eature=related
And here's a better one on a raceway.
http://www.youtube.com/watch?v=WktE9...ature=youtu.be