It all started when I was wondering how slow I was compared to the aliens at iRacing. Back in the good old days of GPL there was site called GPLRank. There your best laptimes were measured against some "default" laptime in order to create a ranking. So I thought I wanted something similar for the iRacing laptimes.
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I consider only qualification and race laptimes. The world records will have a value of 100. For example, if your laptime is 5% slower than the world record, the value for that lap would be 95; if it is 10% slower, the value would be 90. Let's call it alien rating. The average of the qualification and race alien rating build a track alien rating. To get a car alien rating you'll need a number of track alien ratings. For Rookie cars you'll need 4, for all other cars 8 track alien ratings.
They are already there ;) So you don't have to do anything.
Some world records will be unreachable when physics updates are deployed, others will be smashed. That's why only a certain number of tracks count towards the car alien rating. In order to get a better chance to compare the laptimes there are basically two modes available. One is the all-time channel, which should be pretty clear: best laps ever. The other is the season-channel where only data of one specific season is focused.
Don't take these values too serious ;)