[suicideneil]

Excessive heat. Anything over about 190-200*f I think I read once. Trouble with feigaos are that they do run hot under ideal circumstances, so are prone to overheating during a hard session, or in your case they just decide to not play anymore & cook for no apparent reason.

A neu 1515 1y or 1512 2.5d are the most popular upgrades from a feigao, running 12-14 cells or 4-5s lipo/A123. Try to avoid the finned neus as they make it hard to set the mesh with a smaller spur/pinion on the stock emaxx tranny.