Not a lot to say. Each lap is 70.5 miles long, 50 lap, almost 16 hours to complete.
If you're insane enough to do it non afk, the race can be done on unbeatable ai and assists turned off to receive a 100% credit bonus.

1 Lap Race Code - 708 035 642 Time To Complete - 19 Minutes
10 Lap Race Code - 174 496 570 Time To Complete - 3 Hours 10 Minutes
33 Lap Race Code - 580 233 337 Time To Complete - 10 Hours 30 Minutes
50 Lap Race Code - 118 562 834 Time To Complete - 15 Hours 50 Minutes

FE BMW X5 M AFK Tune - 134 931 646

Music -
Song: Vorsa - If Only You Knew
Music provided by BreakingCopyright: https://bit.ly/vorsa-if-only-you-knew