How is the weekly income for the junkyard in GTA V calculated?
Solution 1:
The Car Scrapyard gives you $150 dollars for every car you destroy. You do not need to take the cars to the scrapyard itself.
This is paid out each game week on Monday morning (00:00).
I've just tested this by blowing up two cars on the highway at 23:00 on Sunday. My earnings email for the week came shortly after indicating I'd made $300.
Solution 2:
For every car you destroy you get 150 per week. Mine has capped out at 5000 per week though.