Attention brushless gurus!!!

[Hounddad]

I am building a FOFF rig and want to use a brushless system. However, I would like to go with something sort of inexpensive.

Option 1: Dynamite 5800kv(about $120) set up like the one ini my SC truck.

Option 2: The new 4 pole 2900kv(about $130) system built by Castle for Duratrax.

I have used the Dynamite set up in my Honcho(with paddles) to see how it performs. It was much faster than a stock Honcho.

Of the 2 options which could withstand being geared more aggresively for more speed?

[JohnRobHolmes]

Probably the 4 pole system. Higher slot count, likely better magnets, and a nice low KV.

[benoj]

just so you know the duratrax (castle) system is a 3900kv not 2900kv 4 pole motor, to bad the esc is rated to 2s. on 3s that motor would likely work well in a foff

[SMR 510RR]

Check out tenshock motors. They are comparable to the castle 4 poles but actually have a little more power. I would look at those or the Castle 1410 if you are on a budget, both can be had for $60-70 on ebay.

[Hounddad]

Originally Posted by JohnRobHolmes

Probably the 4 pole system. Higher slot count, likely better magnets, and a nice low KV.

Thanks for the info.

I have searched for basic brushless info to educate myself about what the difference in kv's mean. I didn't find much and the LHS seems to be leaning towards more kv's = more speed.

Could you splain it better for me?== SIMPLIFY, please. VERY CONFUSED.

[SC Convert]

Kv rating = rpms per volt supplied

I use sensored brushless in my scx10.

[JohnRobHolmes]

Originally Posted by SC Convert

Kv rating = rpms per volt supplied

I use sensored brushless in my scx10.

Exactly. KV is RPM per volt. Higher numbers are faster motors.

[Charlie-III]

Originally Posted by JohnRobHolmes

Exactly. KV is RPM per volt. Higher numbers are faster motors.

Which is exactly OPPOSITE from the numbering on BRUSHED motors where the lower "T" number (T = turns of wire on the armature) means a faster spinning motor but less torque.

[JohnRobHolmes]

That is why I also list the KV values for brushed motors, makes it a bit easier to compare. Brushless motors can be rated by the turn as well, but that isn't always listed.

[AreCee]

Originally Posted by Charlie-III

Which is exactly OPPOSITE from the numbering on BRUSHED motors where the lower "T" number (T = turns of wire on the armature) means a faster spinning motor but less torque.

But don't forget that sensored motors are also rated by turns like 21.5, 17.5, etc. and the lower number is faster. These turns are the wires wrapped around the stator.

[Hounddad]

So the 3900kv 4 pole system will have more torque and the ability to turn a higher geared(pinion+spur) better?

If it makes any difference, I am still using NiMh batts. Haven't taken the plunge into LiPo yet.

[SC Convert]

The 4 pole brushless appear to have the torque. I've only seen them advertised for shortcourse trucks. The powerband should work well. Good luck on your build and keep us posted.

[Charlie-III]

Originally Posted by Hounddad

If it makes any difference, I am still using NiMH batts. Havn't taken the plunge into LiPo yet.

In general, the chemistry that supplies voltage is not an issue. If you are pushing the edge (usually rather far off today....) then performance over the whole discharge graph is an issue.
You should be fine overall regardless of battery chemistry as long as voltage & capacity fit the application.

[madkawi650]

I know there is a HUGE difference in 2 pole vs 4 pole. I have a 2726 kv ( I know, weird rating) 2 pole 550 can motor I ran in my slash 4x4 and it's pretty good, lots of torque. UNTILL!!! I bought a castle 2400kv 4 pole motor.. I makes the 2 pole motor look like a toy.. So much smoother and to say it had more torque would be an insult.. It had GOBS! And Gobs more torque.. Literally tears my slash apart.. However.. You better hope you have a high "C" rated lipo if you're running this beast. It will puff a 20"c" 5000 mah turnigy 3s lipo.


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