When Sam asks Dean how long he was out, Dean says 2-3 minutes. Sam tells him it felt like a week.
Ok so based on Lilith's original algorithm
4 months = 40 years in Hell
we get this:
Realtime Helltime
1 month 10 years
1 week 912.50 days
1 day 3128.64 hours
1 hour 7821.60 minutes
1 minute 130.36 minutes
2.5 minutes would be 325.90 minutes, or 5.43 hours
Now based on what Sam tells us,
2.5 minutes = 1 week in Cagetime
Realtime Cagetime
1 hour 168 days
1 day 4032 days 134.4 months (where 30 days= 1 month)
1 month 336 years
12 months 4032 years
18 months 6048 years
Well damn Sam, just DAMN. No wonder there was Hellfire in your eyes ; )