yes, a 13 turn (assuming it's a double-wind) will certainly offer good power, more than a 19T unless it's a real cheapie - $25 or less. I'd drop your pinion gearing at least 3 teeth and try again.
Lower turns generally means more top-end RPMs, but they usually offer more low-end also.
If your motor got really hot along with the pack the brushes may be burnt too. If they're bluish tinted on the end replace them because once the lube is burnt out of them they'll wear your comm much faster.
GV2 Pro, XXX4G+, Blitz SCT, CRC GenXL