The OBD2 interface is limited in the range of turbo pressure readings it can output - -11 in/hg may be the lower limit. I believe +22PSI or so is the upper limit.I installed a turbo gauge today and the readings differ wildly from my Torque app. For those with a gauge can you tell me what it reads while the car is idling? My gauge reads -20 and the app reads -11.00 in/hg. Thanks.