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question about motor turns

question about motor turns

Old 03-10-2011, 01:14 PM
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Default question about motor turns

I'm planning on getting into SC racing. I've been bashing around with a backslash and a rustler for a little while now but am pretty new to the electric stuff. The closest track to me has a few different classes to run in but I need some clarification. The novice class is open to all vehicles but says the cutoff is a 17.5T motor. The 2wd/4wd SC say the cutoff is 10.5T. I've used the search function but didn't really get a good answer on how to understand turns. Some motors (Novak) list the turns of a motor while some others (castle) don't. Is there an easy way to get a rough estimate of what I can or can't run in these classes. My hope is to get a losi xxx sc or associated sc10 for racing but don't want to buy a truck that is to heavy for the motor size to run in the novice class then want to upgrade. If I go 2wd its not as much of a concern but if I go 4wd it might be a concern. Also, for what its worth. The motor has to be able to run on 2's. As always thanks for the help
Darren
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Old 03-10-2011, 01:44 PM
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If they are putting a turn limit to motors, this mean they are adhering to some of the roar standard (Spec racing).

Anything labeled a certain amount of turns is considered legal for that class. Anything novak, tekin, trinity, lrp, etc as long as it falls in the category of legal turns it will be legal for that class.

Ususally a turn rated motor is going to be sensored and run by your ESC with a sensor wire.

Motors with a kv rating only are usually sensorless. Companies making Spec motors (say 10.5-17.5 turns) may include a kv rating with their spec motors and this is usually to satisfy anyone looking, but doesnt amount to much.

Mod classes are usually open and "run what you brung". Only thing staying within limits is the vehicle itself.

As far as 2wd-4wd SCT the 2wd are usually going to have the standard motor while 4wd usually has a bigger motor involved. 2wd 540 can, 4wd 550 can. Most of the time 4wd stays in an open/mod state as they run bigger motors.
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Old 03-10-2011, 01:58 PM
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Thanks for the help. I find it weird that castle has 2 sc labled motors that don't have a turn labled. The 2400kv mmp sct and 3800kv sidewinder sct are both labled as sc but don't have a turn rating. Does not having a turn rating make them illegal if a track adheres to the roar standard? I guess it will be up to the particular track whether or not to allow these motors.
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Old 03-10-2011, 04:32 PM
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Darren,
Most tracks I've visited do allow the Kv motors, but specify what Kv rating are allowed in a particular class. I'd recommend going to your local track and seeing what guys are using, to get a better feel of what you would like to use. I prefer the sensored motors/ESC's and I would select something that will enable you to race in the class that you prefer.
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Old 03-10-2011, 05:29 PM
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Agreed.

Sorry was in a hurry earlier i had to run out.

Like said your best bet is to visit where you will be racing and see if you can get some info there. Most racers are willing to help with advice to get you going. If some are so reluctant to do so, figure out who owns/runs the facility and they can definitely point you in some kind of direction.

Different track and regions are different. Most of what i come across is spec racing. 17.5 13.5 and the like.

I have found the spec turn rated motors (sensored) to drive much better than a sensorless motor rated only with kv.
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Old 03-10-2011, 09:55 PM
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One issue you would have with trying to run Castle motors in a class that specifies a turn is that Kv ratings really are just number there is no way to tell if a 4600Kv motor is actually 4600 and not 5000. This is why they specify a turn. A 13.5 is going to have 13.5 turns of X size wire no matter who makes it. Makeing them all relativly close in speed. Another issue is that Castle doesn't make a motor rated at or close to a 17.5 or a 13.5. Most 17.5 motors have a Kv rating around 2200-2400, some as low as 1700. A 13.5 is roughly 3200-3400, so even a Caslte 3800 is going to be too fast for the 13.5 class. In the end motors that us only a Kv rating are intended for bashing or maybe mod racing. If you're gonna race make life easy and look for a turn rated motor.
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Old 03-11-2011, 08:15 AM
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Sensored motors are described by turns, because (if you unwind the coil) you will find that number of turns on the stator. Turns are real, count-able. Sensored motors are ROAR legal for spec racing only if the mfg has submitted them for approval and they are listed by ROAR.

Sensorless (non-sensored) motors do not have turns and are generally described by Kvs. These motors are not approved for spec racing---they are basically not able to be teched by race directors. Most manufacturers of sensored, BL motors, such as Novak, have added the un-loaded Kv numbers to their motor descriptions as a rough guideline to allow comparisons among various motors.
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Old 03-11-2011, 09:44 AM
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Thanks for all the help guys. It makes a lot of sense now. With that said, anybody have any comments on these motors. These would most likely go in a 2wd short course truck.
http://www.amainhobbies.com/product_...rushless-Motor
http://www.amainhobbies.com/product_...ess-Motor-135T
http://www.amainhobbies.com/product_...rushless-Motor
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Old 03-11-2011, 09:50 AM
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I cant comment on the speed passion motors as I havent used one. Some people seem to like them though.

The D3 = sex! Good strong motor.
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Old 03-11-2011, 10:02 AM
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We have a Short Course section in our store. We offer systems for both 2WD and 4x4 SCTS:

TeamNovak Short Course Store

We have Traxxas compatible SC combos for Plug 'n Play installation into Slashes. We also have a few RMF combos that are an affordable option. Novak products never become obsolete--you can always replace or upgrade to newer Novak products as they are introduced.

Originally Posted by dpcardoza
I'm planning on getting into SC racing. I've been bashing around with a backslash and a rustler for a little while now but am pretty new to the electric stuff. The closest track to me has a few different classes to run in but I need some clarification. The novice class is open to all vehicles but says the cutoff is a 17.5T motor. The 2wd/4wd SC say the cutoff is 10.5T. I've used the search function but didn't really get a good answer on how to understand turns. Some motors (Novak) list the turns of a motor while some others (castle) don't. Is there an easy way to get a rough estimate of what I can or can't run in these classes. My hope is to get a losi xxx sc or associated sc10 for racing but don't want to buy a truck that is to heavy for the motor size to run in the novice class then want to upgrade. If I go 2wd its not as much of a concern but if I go 4wd it might be a concern. Also, for what its worth. The motor has to be able to run on 2's. As always thanks for the help
Darren
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Old 03-12-2011, 09:18 PM
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I'm gonna ask the stupid maybe obvious question. Does a lower turn motor mean more power availability. Counting on the fact that all things are equal (tires, esc, gearing etc).
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Old 03-12-2011, 10:51 PM
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Originally Posted by dpcardoza
I'm gonna ask the stupid maybe obvious question. Does a lower turn motor mean more power availability. Counting on the fact that all things are equal (tires, esc, gearing etc).
In the most basic way possible, yes.
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Old 03-13-2011, 01:20 AM
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Originally Posted by dpcardoza
I'm gonna ask the stupid maybe obvious question. Does a lower turn motor mean more power availability. Counting on the fact that all things are equal (tires, esc, gearing etc).
Yes, but you need to change gearing because the powerband is different. A lower turn motor needs lower gearing (smaller pinion, higher FDR). A lower turn will have a little less torque, but a lot more RPM. Power is proportional to torque times RPM.
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