A BCR has no function with TMCC engines, only MTH engines. The battery is only there to aid sound over dead spots.
They were meant to be run with TMCC which would allow you to program the trailing engine to start in reverse. For conventional running you could reverse the wires on both motors so it would start in reverse. They can be converted to PS3. Many here do this and might contact you. As for slow running I would remove the shell and make sure nothing is rubbing on the flywheel. That could account for the noise and slow running.
Pete
