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Old Jan 21, 2013, 11:28 PM
SleezyK is offline
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United States, AL, Birmingham
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RC Lightning EPX (What KV for best speed/performance)

Hi guys, new to forum, Gotta question though.

I bought a RedCat Lightning EPX drift last December and immediately changed out the tires for some better traction on road tires. I don't want to drift as it turns out.... I want speed and bashing. So I went to my hobbystore, being a newb they sold me at Sidewinder SCT(short course truck) brushless kit...

Why they sold me a SCT for an on road vehicle is beyond me.
The motor is also a 3800KV, and although I keep hearing people say it is capable of speed, I have yet to see it. 30MPH is about where I think I am. Stock gearing on 2S lipo. (3s not handled through ESC).

So now I just purchased a 7700kv sidewinder3 for hopes of getting what I want. But now I am worried that the 7700 only accepts 2s. Then I thought maybe I shoulda got the 5600kv and put it on 3s. I am so new to this and so confused as to what I need to do. Can someone through some knowledge on me?

I have no idea what my tranny ratios are...but i think stock gearing is something like 64Spur/18Pinion(some close to that, may not be exact)
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Old Jan 22, 2013, 10:24 AM
wparsons is offline
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Canada, ON, Whitby
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Why the desire to run 3s? You can get TONS of power/speed on 2s. 7700kv on 2s is over double the RPM (and double the speed if you run the same gearing) of the 3800kv motor. There's no reason you shouldn't be able to get about 50mph out of it easily on 2s.

kv is just RPM / v, and has no direct relation to power output. You will have to run shorter (smaller pinion or bigger spur) for higher kv.
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Old Jan 23, 2013, 05:09 AM
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On 3S you can get the same power to the motor at lower current so less heat buildup. But I agree, on 2S you can go pretty fast.
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