It's called REV from Devtoaster . It make your iPhone connect to the car's ECU from the OBD-II port , and then you can read tons of information such as : Vehicle Speed , RPM , Fuel Consumption , Engine Coolant Temperature , Fuel Pressure , G-force acceleration and braking and Throttle Position . But what's best for me , that it has a GPS track . What it does , after running in a certain lap for 1 time , it saves the track , so when you head to the same track again , it gives you a map of the track and the best speeds for each corner . Now that's some technology .
And the best bit , it's free ! all you need is a OBD-II WLAN device which will connect to the iPhone . It's about 40$ . So would you go to the shop that sells the ECU Control Device for 200$ , or get this free application?
Source : [Devtoaster]