This app is great and free. I can't believe I haven't seen it before or that more people don't know about. Great for people that are mainly on 3g. Haven't tested with LTE.
It turns off data while screen is off and turns on data while screen is on. (Power Saving Mode "on") Default is set to turn on and off every 5 mins in free version. In donate version you can set intervals manually.
No root needed
Works in ART
Sent from my Nexus 4 using Tapatalk