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rc8be 2650kv on 4s too much?

rc8be 2650kv on 4s too much?

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Old 11-30-2010, 01:20 PM
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Default rc8be 2650kv on 4s too much?

Hi all I am currently running the castle 2650kv motor in my rc8be on 3s and i'm wondering if i bump up to 4s will it be too fast for racing? I see alot of guys on here running the 2200kv or even lower kv. I'm also wondering what the benefit of the lower kv motors are. I know you can run them on 5s and 6s but whats the benefit over 2650kv on 4s? Help me out guys.

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Old 11-30-2010, 01:38 PM
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Yes thats too much for 4s. You can use a 3s with a bigger pinion.
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Old 11-30-2010, 01:39 PM
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Definately too much... put in a 3s lipo and you will love it.
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Old 11-30-2010, 01:54 PM
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Well thats the thing i'm currently running a 3s and i dont have enough top end. Im geared 15p 44s. Motor temp is around 120-130 after a 15min race. Its decent when battery is full but the last 5 mins or so before it goes dead there is just not enough. I clocked it a 32mph right before the battery died.
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Old 11-30-2010, 01:58 PM
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Not sure why so many agree with 3s. i think you should have been 4s from the start. Just drop a few teeth on the pinion.
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Old 11-30-2010, 02:10 PM
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Originally Posted by Reubster24 View Post
Well thats the thing i'm currently running a 3s and i dont have enough top end. Im geared 15p 44s. Motor temp is around 120-130 after a 15min race. Its decent when battery is full but the last 5 mins or so before it goes dead there is just not enough. I clocked it a 32mph right before the battery died.
What size 3s pack are you using?

You just need to gear up. You are a little undergeared. 2 or 3 teeth on the pinion will wake her up.

4s on that motor is way overpowered. Wasted RPMs.
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Old 11-30-2010, 02:51 PM
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i run a MMM/2650 in my RC8BE w 14/46 on 4 cell - Its stupid FAST ! my club track is only 50x100 so its dialed back 20% but bigger tracks it gets opened up- Motor temps around 150 after 15min
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Old 11-30-2010, 03:12 PM
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Originally Posted by Alex.Eklund View Post
i run a MMM/2650 in my RC8BE w 14/46 on 4 cell - Its stupid FAST ! my club track is only 50x100 so its dialed back 20% but bigger tracks it gets opened up- Motor temps around 150 after 15min
That's like driving a Ferrari in first gear all day long.
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Old 11-30-2010, 03:15 PM
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Most people that run a 2650 that i've seen run it on 3S. 4S is just way too much with that setup for racing, in my opinion. The ideal setup however is definitely a 6S setup with a low KV motor.
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Old 11-30-2010, 03:30 PM
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Originally Posted by Alex.Eklund View Post
i run a MMM/2650 in my RC8BE w 14/46 on 4 cell - Its stupid FAST ! my club track is only 50x100 so its dialed back 20% but bigger tracks it gets opened up- Motor temps around 150 after 15min
No problem with the motor being that hot? How hot can a motor get before its too hot?

Originally Posted by Tyler350 View Post
Most people that run a 2650 that i've seen run it on 3S. 4S is just way too much with that setup for racing, in my opinion. The ideal setup however is definitely a 6S setup with a low KV motor.
Can someone explain to me why lower kv and more volts is better? You end up with about the same RPM so whats the difference? Or are you saying even lower than a 1800kv? Whats the ideal rpm for 1/8 buggy racing?

1800kv 6s 39960rpm
2650kv 4s 39220rpm
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Old 11-30-2010, 03:43 PM
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Originally Posted by Reubster24 View Post
Can someone explain to me why lower kv and more volts is better? You end up with about the same RPM so whats the difference? Or are you saying even lower than a 1800kv? Whats the ideal rpm for 1/8 buggy racing?

1800kv 6s 39960rpm
2650kv 4s 39220rpm
That's still too high. I've seen 6s work best with 1400kv. You have much more efficiency running on 6s than you would on 4s.

Consider cylinders on a car. You can pump out 300hp on a 4cyl, but a V6 or V8 would produce that power much more easily and efficiently, i.e. it doesn't need to try as hard.

You don't need 5000mah on a 6s to get the same run time (or more) than a 5000mah 4s battery, for the same reason: efficiency.
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Old 11-30-2010, 03:44 PM
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Originally Posted by Reubster24 View Post
No problem with the motor being that hot? How hot can a motor get before its too hot?



Can someone explain to me why lower kv and more volts is better? You end up with about the same RPM so whats the difference? Or are you saying even lower than a 1800kv? Whats the ideal rpm for 1/8 buggy racing?

1800kv 6s 39960rpm
2650kv 4s 39220rpm
Ideal RPMs for 1/8 buggy is around 30k. Setups tend to run the most efficient generally speaking around 30,000 rpms.

Yes, in the above examples, you are basically running the same speed. The difference is the 6s setup will run cooler (ESC and batteries don't have to work as hard) and won't need as many amps to generate the same run time. Amps are what create heat. The lower the voltage, the more amps you need to produce a certain amount of energy.

for instance, a 6s 3300mah battery is equivalent to a 5s 4000mah battery which is equivalent to a 4s 5000mah battery.
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Old 11-30-2010, 04:31 PM
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Originally Posted by Reubster24 View Post
No problem with the motor being that hot? How hot can a motor get before its too hot?



Can someone explain to me why lower kv and more volts is better? You end up with about the same RPM so whats the difference? Or are you saying even lower than a 1800kv? Whats the ideal rpm for 1/8 buggy racing?

1800kv 6s 39960rpm
2650kv 4s 39220rpm
You can run those motors to about 180 safely without issue (according to castle)

I agree w the above poster regarding 6s being more efficient at the same rpm. Ideally, you would run more voltage and less amperage for the same wattage, but with less heat generating waste at the higher voltage.

2650 I'd a great bashing/speed motor, but not really the intended race setup(IMO).

I run 2200's and will likely move down from there. Check out castle's current sales (1800's for like $60!!!)
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Old 11-30-2010, 04:39 PM
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Ya I ran my HB car on 3s with a 2650 and it was still crazy fast. Ya so might have to gear it a tooth lower to take so over kill speed out of the setup.
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Old 11-30-2010, 06:29 PM
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Originally Posted by devnull View Post
You can run those motors to about 180 safely without issue (according to castle)

I agree w the above poster regarding 6s being more efficient at the same rpm. Ideally, you would run more voltage and less amperage for the same wattage, but with less heat generating waste at the higher voltage.

2650 I'd a great bashing/speed motor, but not really the intended race setup(IMO).

I run 2200's and will likely move down from there. Check out castle's current sales (1800's for like $60!!!)
Yeah i saw those and i'm thinking that and a 5s would be pretty nice! what you guys think? 33300RPM.
What size pinion would you guys use with the 44t spur?
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