[Al Skierkiewicz]

Charlie,
From your description, you are running a tank style drive with multiple motors and multiple wheels on the floor. In this configuration, all of your drive motors draw near stall current when ever you turn. (4 motors could easily draw 400+ amps) A sure sign of high wheel friction in turns, is the tendency for the robot to "hop" through a turn.
The fact that your drive motors are getting warm in just a lap or two is an indication that something maybe wrong in addition to the high friction in turns. If you are using multiple motors on your transmissions, are you sure that each motor is running in the right direction? Depending on which transmission you use, the motors run in the same or in opposite directions. Try removing the 40 amp breakers feeding one of the motors on each side of the robot and see if the robot runs correctly. Then swap motor breakers and see if the robot still runs correctly. As an additional check, try moving the wheels by hand and see if there is any significant friction in the drive train. Also try driving the robot with the wheels off the ground and see how long a battery lasts.