Superlap=8:15=Estimated BTG 7:49?? No.
This is the mathematichs for calcucalting BTG vs Supertest/industry configuration (official laptimes for all production cars):
Gantry to Bridge: Abt 25,5 sec (BMW 1 M),
5 sec: the straight along GP-Sträcke is cut (entrance GPsträcke-exit GPsträcke, abt 200 meters straight along T13: 5sec) This is done to allowe drivers to enter T13 (the area they use for pit) without forfilling another lap after finishing their record attempt.
1,5 sec: During trackdays with open pitlane/Supertest/industry configuration and VLN, we pass Bridge at almost topspeed (abt 250kmh for 1 M) as we keep flat on the long straight to Dottinger Höhe, whilst at BTG without open pitlane we pass Bridge after accellerating only from the cones after entering at main entrance. For the 1 M this adds up to a speed of abt 150-160 km/h when passing Bridge. That costs abt 1,5 sec extra compared to flying by at 250km/h.
Total difference BTG without open pitlane vs Superlap is abt 18 sec for the BMW 1 M. For a car with higher topspeed, like the 991 RS, the difference is abt 17 sec, maybe a bit less.
Estimated BTG without open pitlane fro BMW 1 M: 7:57, very far from the 7:49 claimed. Upgraded tires and suspension and pads will however cut that dramaticly and make 7:50 realistic.