[Patrick]

The guys at my track that are running 4s 4900's (pretty much all of them are flightpower cells) in truggys can get 12 -15 minutes maximum. That's works out to 25 maximum off an 8000 mah pack. I run 5s to get the same power and I used 6400 mah in 26 minutes of racing, so I think I can get just over 30 minutes.
At a decent sized track geared for ~35mph I wouldn't expect to get 30 minutes from an 8000mah pack, unless you spend 5 of those minutes upside down.

I use a neu 1515 2.5D and an unmoded quark 125. The night I did 26 minutes of racing was nice and cool, so I the temps on my esc and motor were under 100f. The week before that we were doing 5 minute races in the middle of a 100f day. I didn't get temps, but the motor and esc were getting quite hot. No thermals though. Once it start getting dark and cooled down a bit, the motor and esc temps dropped to just being warm after the race, so ambient temp seems to make a big difference. Same gearing, tires and setup were used, and at the same track.