I just came across this app in the Google Play Store. Together with an OBD2 Bluetooth Adapter it lets you see lots of real time information about your vehicle.
Dyno / Dynomometer and Horsepower/HP & Torque
* Can read Transmission Temperatures (vehicle dependant)
* 0-60 speed timings - more accurate than just using plain old GPS - see how fast your car is (or truck )
* CO2 emissions readout
* Customisable dashboard & profiles
* Video your journey using the Track Recorder plugin with onscreen OBDII data overlay - a black box for your car/truck!
* Automatically send GPS tagged tweets directly to twitter (for example if you are going on a road trip)
* Massive fault code database for lookup of fault codes from different manufacturers
* Theme support (choose from different themes to change the look of your dashboard)
* Send logging information to web or email CSV/KML for analysis via excel / openoffice reader
* Heads up display / HUD mode for night time driving
* Compass (GPS Based) that won't suffer magnetic interference
* GPS Speedometer/Tracking and realtime web upload capability - see what you were doing and your engine, at a point in time
* Turbo boost feature for vehicles that support MAP and MAF sensors (VW & Golf / Audi / Seat etc supported)
* Alarms and warnings (for example if your coolant temperature goes over 120C whilst driving) with voice/speech overlay
* Car dock support
* Graph data
* Able to share screenshots to Facebook, Twitter, Google+, Email, etc
* AIDL API for third party apps, A simple Telnet interface for developers to talk to the adapter, and an OBD scanner.
* Works on tablet devices like the Motorola Xoom, Dell Streak, Samsung Galaxy Tab and Nook