Wanna go brushless, but how?

Dopeman

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I want to convert my Raider Xl Mega to brushless. I was looking at this Castle setup.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDYJC&P=3#tech

I don't know if that is all I need? The rest of the car is stock. Also, would love for someone to explain the whole Kv thing on the motors. Using only one battery, probably 3s lips, should I look at a 3900kv, a 4500kv, I think they even had one rated at 7700kv? Don't fully understand the rating. I want power and speed from this rig. You guys are my go to guys for the arrma knowledge.
 

donp

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You can go to castle creations site and read the chart on which system is best for you. The short course systems would be a good choice in my opinion cosidering you have an 1/8 scale 2wd buggy. You may want to check your diff, if its not metal gears you will need to upgrade it, the drive cups, and dogbones.
 

Dopeman

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You can go to castle creations site and read the chart on which system is best for you. The short course systems would be a good choice in my opinion cosidering you have an 1/8 scale 2wd buggy. You may want to check your diff, if its not metal gears you will need to upgrade it, the drive cups, and dogbones.


I believe the diff is a metal gear diff. I would be upgrading the tranny and spur gear to metal gears. Drive cups and dogbones are already metal parts. What would I need to upgrade those to?
 

donp

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I don't know if there are aftermaket available foe these but, I recall seeing a thread on here about using the stock pars from the brushless raider axles. I would leave the transmission alone unless you break something. I know alot of the other manufacters like AE and traxxas have a mix of metal and plastic gears in the trans which I do own and never had a problem on brushless.
 

chargh

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The Kv rating of a motor can be hard to rap the brain around but it is fairly simple.
Say you had a 3900 Kv motor, what that means is for every volt you have running through the motor the motor will spin 3900 times a minute.
For example if the motor was receiving 3.75 volts then it would spin at 14625 RPM (3900 Kv X 3.75 volts = 14625 RPM).
A 3s battery would spin the same motor at 43875 (3900 Kv X (3.75 volts X 3(for 3s battery)) = 43875 RPM.
3.75 volts seems to be the "standard" voltage used when calculating the RPM's of a motor
 

Dopeman

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The Kv rating of a motor can be hard to rap the brain around but it is fairly simple.
Say you had a 3900 Kv motor, what that means is for every volt you have running through the motor the motor will spin 3900 times a minute.
For example if the motor was receiving 3.75 volts then it would spin at 14625 RPM (3900 Kv X 3.75 volts = 14625 RPM).
A 3s battery would spin the same motor at 43875 (3900 Kv X (3.75 volts X 3(for 3s battery)) = 43875 RPM.
3.75 volts seems to be the "standard" voltage used when calculating the RPM's of a motor

So higher Kv = higher rpm. So higher Kv = more speed. Does that also equate to less torque?
 

chargh

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I wish I could help you with that but I have no knowledge of the Raider XL.
In fact I am just starting out in RC vehicles. I have been into RC helicopters and planes for about 6 years.
Thought I would try to "keep em on the ground" for now.
 

donp

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You may want to check the motor specs, being 4400kv, it may not be capable of 3s. To run 3s is usually 4000kv and under.
 

Dustin Mustangs

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An important thing to keep in mind with KV is gearing. You have a limited amount of gear options available (spur and pinion) without Frankensteining parts from other vehicles. They will give you a range of easily attainable final drive ratios. Those, along with your tire diameter, battery voltage, and motor KV determine your (theoretical) top speed. There are online calculators that do this math for you. Use them and the high and low end of your final drive options to get a corresponding range of suitable KV for a given top speed. Then pick a KV close to the middle of this range and gear accordingly.

Clear as mud? :wtf:
 
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donp

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You should be fine with that setup, you can find a chart on castlecrations.com to get a base line for your gearing. Just be sure and check your motor temps, if you don't have an infared thermometer a basic rule of thumb is if you can't hold your finger on the motor for more than 5 seconds, it'to hot.
 

Unusual RC

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The BLX system for the RaiderXL is a good starting point:
- 60A Esc (2,0A/6,0V BEC) sensorless
- 3650 3800kV 4-pole motor

With that on 3S the power is already more than ridiculous! Make sure you buy the 32p spur and motor pinion from the BLX manual.

So a matching set will be fine, like the Sidewinder sv3 with 3800kV motor from Castle.
But be aware that BEC output of Castle will not allow powerful servo's.
 

Dopeman

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The BLX system for the RaiderXL is a good starting point:
- 60A Esc (2,0A/6,0V BEC) sensorless
- 3650 3800kV 4-pole motor

With that on 3S the power is already more than ridiculous! Make sure you buy the 32p spur and motor pinion from the BLX manual.

So a matching set will be fine, like the Sidewinder sv3 with 3800kV motor from Castle.
But be aware that BEC output of Castle will not allow powerful servo's.

With the Raider being light and only 2wd, do I really need a more powerful servo than stock? To me, it does a fine job.
 

Unusual RC

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With the Raider being light and only 2wd, do I really need a more powerful servo than stock? To me, it does a fine job.

Since this is the MEGA version, it's servo has plastic gears. They will strip sooner or later.
Even the Raider 1/10 version's servo is known for stripping.

Servo speed is not the first reason to upgrade.
Personally I found the stock servo a bit slow. But I do race my Fury on a track. For bashing it is sufficient
 
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