Turn VS Kv
 

Can anyone describe to me how turn and kv work. All of these motors either run turns or kv it's kinda confusing. Thanks

All turn motors have a KV rating also, it just depends on how a company wants to label their motors.

Let me explain:
Castle, and most 8th scale motors are usually labeled as KV only. I think only speed-passion uses a turn denomination for their 8th scale stuff.

The KV-Turn is standard across companies.

The only one I know by heart is 17.5 turn, which is 2200kv. No matter which 17.5 turn motor you get, it will be 2200kv, and vise versa.

Hope that helped.

It is confusing as Hobbywing state their 3300kv sensored motor as a 10.5 turn and everyone else calls this a 13.5 turn motor.
And to make it more confusing they call their non sensored motor 3300kv a 13.5.
I tend to go by the motors kv these days as it gives you a true indication of a motors potential.

All 17.5 motors are not 2200, and that includes roar approved 17.5's and kv and turn are not as you noted 'vise versa' at any rating.

All 17.5 turn motors do have 17.5 turns (the wires inside the can) many other factors come into play to determine the kv rating. Manufacturers usually provide this figure.

Kv ratings and torque have more to do with each other in a visa versa sort of way; as kv goes up torque goes down and visa versa, kv down torque goes up.

So the higher the kv you go the power and rpm's?

Kv = rpm per volt of a motor, it is the only measument that we can compare between motors. The higher the kv the more power the motor wll generate but it has to be matched to the car (gear ratios and voltage used etc)

Using "turns" or "wind" to describe a motor is misleading. I have just compared several brands and very few match up kv to wind so its not a level playing field.

The sooner these companies realise not all car guys are stupid the better off we will all be

So would a mamba monster with a 2650 kv castle motor on a 4s 5000 mah 20c in a rc8t with stock gearing be good for a medium to large size track?

Too much motor. 2200kv would be better but still a lot of power.

ok, but how is that size battery, would you go bigger. and where is the best place to buy good cheap batteries.

4s is fine. If you want more Mah for longer run times you will have to look at something. Hobbyking has the cheapest ones.

You also have to look at efficiency. The More voltage you have the less Amperage you will use for a given Power. P=V*I. Now if you go Up in voltage the motor's RPm will go up. That can be good but for racing it is usually kept about 30000 theoretical max RPM . Now to get longer run times with the same power as a 4S 2000kv setup with a 5S 1700kv or 6s 1400kv.

The 5 and 6S setups will use less Mah per min therefore longer runtimes on the same Mah batteries. But heavier batteries too.

ok a REALLY BIG thanks guys you really cleared some stuff up for me

Wait what?

How can you actually have a HALF of a turn?

Have you ever wound a motor before?

You can have a half a turn when you start the wire at one end of the stack/stator and end it at the other end so the last "turn" is only 1/2 way around the stack/stator. All Novak motors are in half turn increments because the wires start at the back of the motor and are connected to a common ring at the front of the motor.

This is more common in brushless motors but some slot car motors in the 1960s were done in what was called, at the time, a "Star" wind where the 3 wires were soldered together at the back end of the stack opposite the commutator.

Have you ever wound a motor before? I have - I had my own brand of slot car motors in the late 1960's.

Interesting. Staring at the inside of the can on the couple BL motors here, didn't realize that was possible.
Also...
Argument aborted :D