Before each race, do some hotlaps in hotlap mode in the game - click hotlapping in the main menu:
select the appropriate track and car and drive a clean lap. Don’t forget to select the correct setup for your car and take only as little fuel as necessary. After you cross the finish line on a clean lap, press “1” to save the replay.
Then go to http://www.lfsworld.net/?win=hotlaps&whichTab=trackcharts - Upload a HotLap. Login with your LFS username and WEB password.
Click browse and get to the LFS .spr replays directory
and choose your replay file. Click upload and you are done! Now you can see your time in the HotLap chart and we can use it to put you in your performance group.