Question About kV

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Old 03-10-2015, 08:46 PM
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Default Question About kV

Does higher kV automatically give more top end at the sacrifice of torque? I

I'm going to be running a 2S setup in a converted 1/8 buggy to SC and a 1/8 buggy. Both of these vehicles carry a lot of weight (8lbs) and I am looking for the best balance of speed and torque. I want to be able to clear the jumps on an indoor clay tracks, but not get outran down the straight, by everyone (17.5 buggies run with me down straights; currently running 4500kV).

Should I go up or down in kV?
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Old 03-10-2015, 08:55 PM
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WHat motor are you running right now? I run a Castle SCT Pro 2400Kv on 2s in my DESC410 and there is no way a 17.5 buggy can hang with me on the straight.

Does your motor make enough torque to accelerate the weight? It sounds to me as there is something very wrong with your combination. 1/8 buggy on 2s seems to me like a tough thing to do without spending a bunch of coin.
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Old 03-10-2015, 09:16 PM
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Originally Posted by 1/4milecrazy View Post
WHat motor are you running right now? I run a Castle SCT Pro 2400Kv on 2s in my DESC410 and there is no way a 17.5 buggy can hang with me on the straight.

Does your motor make enough torque to accelerate the weight? It sounds to me as there is something very wrong with your combination. 1/8 buggy on 2s seems to me like a tough thing to do without spending a bunch of coin.
Currently running Viper Copperhead-R combo (sensorless 4 pole system). Motor is 4500kV. That is why I'm asking the question. I believe that I need a motor that has more torque to carry the weight, but should I increase or decrease kV to get it, there are lots of 4 pole motor options. You say you're running 2400kV on 2S? Really? That gives the correct RPM to get good speed?
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Old 03-11-2015, 07:22 AM
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What gearing are you running. What is your Motor/ESC temps?
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Old 03-11-2015, 09:40 AM
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Originally Posted by masher81 View Post
What gearing are you running. What is your Motor/ESC temps?
Currently running 46/16 (mod1). Tried various combinations of spur and pinion. Current temps are at 160 (motor), 100 (ESC), and 105 (battery) with a full pack run (6500mah 65c).
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Old 03-11-2015, 09:59 AM
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Higher KV will produce more RPM's and less torque

Lower KV will produce less RPM's but more torque.

But a lot other factors come into play though...like gearing.
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Old 03-11-2015, 10:54 AM
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Size of the can is important, as is the wattage of said can (motor).

For 1/8th scale, recommend you get a can with at least 40mm Diameter and 68mm length.

Lower KV is used for heavier RCs, has more torque, can be geared up to be a speed demon, but needs higher input voltages to achieve high RPM.

Higher KV is for lighter RCs and doesn't require high voltages to achieve high RPM. But if used in a heavy RC, then chances are you'll get dusted down the straights from a lower KV motor geared properly.
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Old 03-11-2015, 11:31 AM
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Originally Posted by skeasor View Post
Higher KV will produce more RPM's and less torque

Lower KV will produce less RPM's but more torque.

But a lot other factors come into play though...like gearing.
Ok...so as a general, wide sweeping, rule, the heavier the vehicle the lower kV you should run so as to have more torque than horsepower?
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Old 03-11-2015, 11:42 AM
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Originally Posted by eXXon View Post
Size of the can is important, as is the wattage of said can (motor).

For 1/8th scale, recommend you get a can with at least 40mm Diameter and 68mm length.
I can run this as a 2s application and still get good rpm? Or will I have to gear it way up to run with other 4x4 SC?

Originally Posted by eXXon View Post
Lower KV is used for heavier RCs, has more torque, can be geared up to be a speed demon, but needs higher input voltages to achieve high RPM.

Higher KV is for lighter RCs and doesn't require high voltages to achieve high RPM. But if used in a heavy RC, then chances are you'll get dusted down the straights from a lower KV motor geared properly.
Ok, this makes sense...thanks!
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Old 03-11-2015, 06:07 PM
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You want a high kv 4 pole 550 motor. What you have shouldn't be slow though, should be fast as a mod buggy
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