Well I tell you what. my bro has a 65 turn motor in his crawler and it has WAY more torque than the 27 turn it came with.

Direct motor to motor comparisons, not including a transmission and drivetrain, would still agree with what I stated. If you simply dynoed a 27 turn motor, and then a 55 turn motor, you would definitely see the 27 turn motor makes more torque. The forumlas and number don't lie.

The difference is the power band of the motor. Since the 55 turn motor spins slower (because it's windings are heavier with more turns, and because they have more resistance) it's max torque is produced at a lower RPM.

A 27 turn motor is more efficient by design (less internal resistance), and while it draws more current because of that, it also produces much more torque, but at a higher RPM. Chances are the gearing on the crawler would have had to be changed to allow the 27 turn motor to hit it's sweet spot in the power band. The 27 turn motor could have very well been lugging at a much less then ideal [lower] RPM. Had you simply swapped the pinion/spur gear to allow the 27 turn motor to hit the same wheel speed as the 55 turn motor, I can guarantee it would have produced way more torque.

Without going into to much depth, you have to look at a motor's current draw, at a specific voltage, and it's RPM, to determine the wattage and torque measurements. There are plenty of formulas, but in the end, a lot of it can be simply proven by ohm's law.

If the motors were wired in series, the second one would only have access to the voltage and amps not consumed by the first one, making it less powerful. In parallel they have equal access to the power source so both can make full power.
I remember this experiment in 9th grade science; we wired up light bulbs in series, and the last one in the series (farthest from positive battery lead) was always noticably dimmer than the first bulb. Wiring them in paralell caused all bulbs to glow with the same brightness as the first (full power). Home wiring is always done with the receptacles (appliances) in parallel or the voltage drop would be severe at the end of the chain.

But which end do you start from + or - ? :eek: :D

If the motors are on a common gear then they have no choice but to be equal in every way.

Awesome observation. ;)

Kind of, but not quite 100% clear. In series circuits, voltage divides among all the loads, and current is equal. It's basic Ohm's Law stuff. If the loads are equal in resistance, the voltage each load recieves is going to be equally split up as well. In the case of a starter box, the motors would likely be identical. So instead of them seeing 12 volts, each motor would see half that, at only 6 volts. Current would be identical for each motor (load), regardless of the internal resistance.

In parallel circuits, current divides, and voltage stays the same.

This is true, but the bulbs you used must have all been different. In the real world, even identical bulbs are not really identical because of variances in the manufacturering process. No doubt, the same with motors. Resistances will never be 100% the same. The largest load (greatest resistance) will always drop the most voltage.

So I should wire my starter box batteries in series and then my motors in parallel?

After reading this thread, went to have a look at my twin motors starter box & realized that the motors were wired in series.

Just changed them in parallel... & it works real fast. :nod:

Thanks for the info guys..