1. Download Telemetry from here. And extract in the rfactor folder.
2. A telemetry folder will be created there, with an exe file inside called f1_telemetry.exe.
3. Go to the UserData/Player Name_Folder (where Player Name is your name in the game ) and open with the Notepad the Player_Name.plr file.
4. Under [ DRIVING AIDS ] you’ll see some “Data Acquisition” lines, put them like this:
Data Acquisition Version=”1″ // Version of vehicle data to write out
Data Acquisition Rate=”8″
Data Acquisition In Race=”1″
Data Acquisition EXE=”D:\games\rFactor\Telemetry\f1_telemetry.exe”  // Your game path
Data Acquisition File=”D:\games\rFactor\Telemetry\vehicledata.spt” // Your game path
5. Save the PLR file
6. Now it will work like F1 Challenge. Your last run will be saved as vehicledata.spt that you will need to load with the f1_telemetry.exe file to see the laps you made with all the data about it. (press “Load Session” in telemetry to load your last lap)