Brushless motors I'm lost

[thatwelderguy69]

I recently got back into building RC's and I scored a Traxas E-Maxx and about a grand in parts for $300. It has two Titan 550 motors in it and has mostly all steel drivelines and shafts. I I bought the conversion plate to convert it to just one motor, but I don't have a clue on what I brushless motor i need to look into. Mainly the Kv part. I don't know which Kv rating that I would need to produce the same or more performance that i currently have and this thing screams. I went and read about the Kv rating and what it means, but that doesn't help me understand what Kv rating would work for me. Like i have seen, 3500Kv, 3800, 400, 5000Kv etc. etc. What Kv rating should I consider? OR,,, should I just stick with the same motors and upgrade the ESC so it will accept an 11.1 battery. I wasn't paying attention when I dropped two 11.1 batteries in it and smoked the steering servo. OOppss! I was looking at a Spektrum

Firma 85A Brushless Smart ESC / 3300Kv Sensorless Motor Combo or​

Spektrum XSEMC01 FIRMA 85A BL Smart ESC/3300Kv Sensorless Mot Combo​

I Just need some advice on this from those of you that have more experience than I do. I was looking for a previous thread that might've answered my question, but I didn't find anything after 10 minutes of searching. Thank you so much

 

[Lukedavis]

I recently got back into building RC's and I scored a Traxas E-Maxx and about a grand in parts for $300. It has two Titan 550 motors in it and has mostly all steel drivelines and shafts. I I bought the conversion plate to convert it to just one motor, but I don't have a clue on what I brushless motor i need to look into. Mainly the Kv part. I don't know which Kv rating that I would need to produce the same or more performance that i currently have and this thing screams. I went and read about the Kv rating and what it means, but that doesn't help me understand what Kv rating would work for me. Like i have seen, 3500Kv, 3800, 400, 5000Kv etc. etc. What Kv rating should I consider? OR,,, should I just stick with the same motors and upgrade the ESC so it will accept an 11.1 battery. I wasn't paying attention when I dropped two 11.1 batteries in it and smoked the steering servo. OOppss! I was looking at a Spektrum

Firma 85A Brushless Smart ESC / 3300Kv Sensorless Motor Combo or​

Spektrum XSEMC01 FIRMA 85A BL Smart ESC/3300Kv Sensorless Mot Combo​

I Just need some advice on this from those of you that have more experience than I do. I was looking for a previous thread that might've answered my question, but I didn't find anything after 10 minutes of searching. Thank you so much

The Firma 85a escape are WAY WAY WAY to small for a truck to that size. I personally would go for either a HW Max8 G2 2250kv motor combo, or, the Castle Creations Mamba X e-buggy edition with the 2200kv motor combo. Or, you could go smaller and get the HW Max10 G2 140a combo with the 2500kv motor.

 

[WickedFog]

Most ESC's and motors work for a certain scale/weight/drivetrain (ie 2wd or 4wd). I am not familiar with the E-Maxx, but it weighs 9.25lb, and is a 4wd monster truck. So if it were me, I would probably go with the 1/8 Castle Mamba Monster X combo with a 2200kv motor. Just a guess though, but it should be a beast with the right gearing.
https://www.towerhobbies.com/produc...ss-motor-combo-6.5mm-bullet/CSE010014503.html

 

[9x19]

I run a 2200kv in my brushless EMax.

If your twin-motor/esc are unmodified, you can trade them in to Traxxas for their 6S ESC and 2200 kv motor. It will cost $165, but still cheaper than most other options.

https://traxxas.com/powerup

 

[thatwelderguy69]

Does the Lower Kv rating make it faster? I also want to upgrade the Axial SMT10 monster truck and the Axial SCx10 to brushless. Money isn't really an issue, but I also don't feel like paying $400 for a motor and ESC
I'm still figuring out how to reply to each posting. So thanks to everyone commenting. I appreciate each response. I'm not computer illiterate, I've just never been on a forum.

I run a 2200kv in my brushless EMax.

If your twin-motor/esc are unmodified, you can trade them in to Traxxas for their 6S ESC and 2200 kv motor. It will cost $165, but still cheaper than most other options.

https://traxxas.com/powerup

Thanks, that's pretty cool

Most ESC's and motors work for a certain scale/weight/drivetrain (ie 2wd or 4wd). I am not familiar with the E-Maxx, but it weighs 9.25lb, and is a 4wd monster truck. So if it were me, I would probably go with the 1/8 Castle Mamba Monster X combo with a 2200kv motor. Just a guess though, but it should be a beast with the right gearing.
https://www.towerhobbies.com/produc...ss-motor-combo-6.5mm-bullet/CSE010014503.html

Thanks, I'll look into that as well

 

[WickedFog]

Does the Lower Kv rating make it faster? I also want to upgrade the Axial SMT10 monster truck and the Axial SCx10 to brushless. Money isn't really an issue, but I also don't feel like paying $400 for a motor and ESC

Lower kv = lower RPM.
1000kv x 11.1v = 11,100 RPM
2200kv x 11.1v = 24,420 RPM.

It isn't just "hey, let me put the highest kv motor in to make it faster". At some point, too much kv will be too much for the RC, and the motor will generate a lot of heat trying to lug the RC around, and it will fry it. That's why I said motors are designed for certain applications. In some situations, a lower kv motor may actually make the RC run faster due to steeper gearing/less heat.

Also, you should buy an infrared temp gun. If your ESC/motor get above 160°F, you are at a much higher risk of burning them up. The MMX/2200kv should run really cool, and allow a good range of gearing to achieve your desired performance, but I would definitely have a temp gun handy, as that will allow you to tune the gearing. If it's running 120°F, try stepping up to a higher tooth pinion for more speed. Just know that more top end speed means you will sacrifice low end grunt. So tune it to run the way you want it. Just keep things below 160°F

And I know this isn't part of your questions, but just so you know, changing tire diameters affects all this heat/speed/low end punch as well. I'm just throwing this out there because I have seen people new to RC think they can put whatever tires they want on their RC, without changing the gearing, and wonder why they have electronics/slipper clutch/part failures.

 

[thatwelderguy69]

Lower kv = lower RPM.
1000kv x 11.1v = 11,100 RPM
2200kv x 11.1v = 24,420 RPM.

It isn't just "hey, let me put the highest kv motor in to make it faster". At some point, too much kv will be too much for the RC, and the motor will generate a lot of heat trying to lug the RC around, and it will fry it. That's why I said motors are designed for certain applications. In some situations, a lower kv motor may actually make the RC run faster due to steeper gearing/less heat.

Also, you should buy an infrared temp gun. If your ESC/motor get above 160°F, you are at a much higher risk of burning them up. The MMX/2200kv should run really cool, and allow a good range of gearing to achieve your desired performance, but I would definitely have a temp gun hsndy, as that will allow you to tune the gearing. If it's running 120°F, try stepping up to a higher tooth pinion for more speed. Just know that more top end speed means you will sacrifice low end grunt. So tune it to run the way you want it. Just keep things below 160°F

And I know this isn't part of your questions, but just so you know, changing tire diameters affects all this heat/speed/low end punch as well. I'm just throwing this out there because I have seen people new to RC think they can put whatever tires they want on their RC, without changing the gearing, and wonder why they have electronics/slipper clutch/part failures.

thank you for that in depth response. Having been building full size 4x4's and rock crawlers for the last 30 years, I know all about gearing and bigger tires. I have two mega$$$ rock crawlers at my shop. One has 4:56 gears and the other has 5:13 gears, running 42" Super Swampers. I don't really care if it's fast than what it is now, because you better be paying attention to it once you shift into high, because this E-Maxx flat screams with stock motors. So I will definitely take the suggestions seriously and look into the motors that were suggested. Thank you again

 

[WickedFog]

thank you for that in depth response. Having been building full size 4x4's and rock crawlers for the last 30 years, I know all about gearing and bigger tires. I have two mega$$$ rock crawlers at my shop. One has 4:56 gears and the other has 5:13 gears, running 42" Super Swampers. I don't really care if it's fast than what it is now, because you better be paying attention to it once you shift into high, because this E-Maxx flat screams with stock motors. So I will definitely take the suggestions seriously and look into the motors that were suggested. Thank you again

Cool beans. Got any pics?

Also, I forgot to mention the servo problem you have. The ESC uses an internal BEC to control the output voltage to the receiver. This voltage is constant no matter what battery you put in. So I can't see how stepping up to more voltage could have caused the servo to fry, unless the servo is being powered directly from the batteries. Traxxas servos are pure garbage. So if you had the stock servo, running off the receiver, I'd guess it was just its time. They are usually short lived servos.

 

[thatwelderguy69]

Cool beans. Got any pics?

First of all, I finally found someone else who says coo beans, lol yeah, I've got pics. I'm currently getting ready to upgrade all the steering on the Emaxx and I'm getting ready to go brushless on the Axial SMT10 I built. Just finished painting anew body for the E-Maxx.

Cool beans. Got any pics?

Also, I forgot to mention the servo problem you have. The ESC uses an internal BEC to control the output voltage to the receiver. This voltage is constant no matter what battery you put in. So I can't see how stepping up to more voltage could have caused the servo to fry, unless the servo is being powered directly from the batteries. Traxxas servos are pure garbage. So if you had the stock servo, running off the receiver, I'd guess it was just its time. They are usually short lived servos.

ok. I didn't know and it did have the original servo. I already upgraded that. I'm going to be looking at some of the motors that were suggested to me. thanks again

 

[tntpoof]

so the pipes and bong just fell of that work bench? LOL. I have a US bong 3 stage. I'm into dugouts.
Brushless has some misunderstood info one is lower kv has more torque. higher kv is faster in long run. both are wrong.
if your going to upgrade steering servo go above what one might need in oz keep sweep the same.more peed never hurts
id go 150 amp+ i a esc for that max.also a servo saver never hurts any rig.

 

[thatwelderguy69]

so the pipes and bong just fell of that work bench? LOL. I have a US bong 3 stage. I'm into dugouts.
Brushless has some misunderstood info one is lower kv has more torque. higher kv is faster in long run. both are wrong.
if your going to upgrade steering servo go above what one might need in oz keep sweep the same.more peed never hurts
id go 150 amp+ i a esc for that max.also a servo saver never hurts any rig.

lmao,,,yeah, i noticed after I uploaded the pic that my bong was on my desk. ooppsss, I'm legal for it though. lol that really helps explain it. I have my head still stuck with my 4x4's that the bigger the number, the lower the gear. I'm catching on slowly. lol I'm actually upgrading the steering right now with an aluminum bell crank kit, servo saver and high torque servo. I need to, because I have bigger tires coming. But just like with me when I'm four wheeling, i like to mash the skinny pedal and I do the same with my RC's. So I'm finding the weak points pretty fast. thanks

 

[WickedFog]

lmao,,,yeah, i noticed after I uploaded the pic that my bong was on my desk. ooppsss, I'm legal for it though. lol that really helps explain it. I have my head still stuck with my 4x4's that the bigger the number, the lower the gear. I'm catching on slowly. lol I'm actually upgrading the steering right now with an aluminum bell crank kit, servo saver and high torque servo. I need to, because I have bigger tires coming. But just like with me when I'm four wheeling, i like to mash the skinny pedal and I do the same with my RC's. So I'm finding the weak points pretty fast. thanks

Yeah, the bigger the number means a lower gear if you are talking about the ratio As in a smaller pinion and bigger spur will create a lower gear ratio (higher ratio number). You get it. I am an old gearhead too, but mine was with corner carvers instead of 4x4's.

And yeah, tnt is correct. People often say lower kv motors have more torque, but it's not really true. The 2200kv range should be pretty decent for your E-Maxx though.

For the servos, some will have torque and speed listed at different voltages. You will notice they develop more torque and faster speed at higher voltages. The way to achieve that is by using an external BEC, like a Castle 10A. It will allow you to adjust your input voltage to the receiver by bypassing the power output leads on the ESC to deliver the proper voltage for your servo, as long as the receiver can handle it. Most ESC's internal BEC's are weak, and don't allow you to get the most out of your servos. Like some internal BEC's only go up to 6v. So that's where it's nice to have a good external BEC to control that, especially if you have high voltage servos.

 

[thatwelderguy69]

Yeah, the bigger the number means a lower gear if you are talking about the ratio As in a smaller pinion and bigger spur will create a lower gear ratio (higher ratio number). You get it. I am an old gearhead too, but mine was with corner carvers instead of 4x4's.

And yeah, tnt is correct. People often say lower kv motors have more torque, but it's not really true. The 2200kv range should be pretty decent for your E-Maxx though.

For the servos, some will have torque and speed listed at different voltages. You will notice they develop more torque and faster speed at higher voltages. The way to achieve that is by using an external BEC, like a Castle 10A. It will allow you to adjust your input voltage to the receiver by bypassing the power output leads on the ESC to deliver the proper voltage for your servo, as long as the receiver can handle it. Most ESC's internal BEC's are weak, and don't allow you to get the most out of your servos. Like some internal BEC's only go up to 6v. So that's where it's nice to have a good external BEC to control that, especially if you have high voltage servos.

I'll have to look into the BEC thing. I went ahead and bought a

Velineon VXL-6s Brushless Power System, 2200Kv Motor & ESC​

that'll get me started with a brushless motor. I still spend money like water on 4x4's, that's all I need is another hobby. lol but at least it's one hell of a lot cheaper to make upgrades.

 

[F.R.S. Ninja_007]

Can’t you use the Traxxas power up program to get brushless? I don’t know what ESC you’d use though…

 

[Chubaka]

so the pipes and bong just fell of that work bench? LOL. I have a US bong 3 stage. I'm into dugouts.
Brushless has some misunderstood info one is lower kv has more torque. higher kv is faster in long run. both are wrong.
if your going to upgrade steering servo go above what one might need in oz keep sweep the same.more peed never hurts
id go 150 amp+ i a esc for that max.also a servo saver never hurts any rig.

That's a vase, the flowers just died and decayed is all.

 

[thatwelderguy69]

Can’t you use the Traxxas power up program to get brushless? I don’t know what ESC you’d use though…

yeah, 9x19 mentioned that earlier and it comes matched with a ESC. But I didn't want to do the exchange.I wanted to keep the motors it has for other things. So I just bought it outright for $260something

That's a vase, the flowers just died and decayed is all.

thats funny as poop, lol

 

[tntpoof]

Right the lighter had no effect on the burning flower.

 

[Chubaka]

Right the lighter had no effect on the burning flower.

New escs and motors often need soldering and heat shrink.

 

[Bogda89]

First of all, I finally found someone else who says coo beans, lol yeah, I've got pics. I'm currently getting ready to upgrade all the steering on the Emaxx and I'm getting ready to go brushless on the Axial SMT10 I built. Just finished painting anew body for the E-Maxx.

View attachment 165670

View attachment 165672

ok. I didn't know and it did have the original servo. I already upgraded that. I'm going to be looking at some of the motors that were suggested to me. thanks again

That's an oldest generation of emaxx. I have one, paid 100$ for it. It's a two speed.

I would highly suggest to keep it stock or if you convert it to brushless to go with very mild setup. Those cars are not designed for brushless power and if you put anything higher than 3 s you will destroy something as soon as you pull the trigger.

If you plan to bash and jump this thing it will brake very easy. It's not worth putting any money into it and actually by doing mods you will lower it's value. Some collectors would pay more for all stock vintage emaxx than modified. But it's not very sought after truck with crazy price.

If you really want to convert to brushless I would go with hobbywing quick run 120 ESC and 3660 motor with around 3000 kv stock gearing. You don't need different motor plate, just use one motor.

I have newest emaxx second gen brushless edition that I bought as a roller for 60$

If you really want to push your luck that go with 3670 motor.

If you need something to bash and abuse Maxx v2 is the way to go

 

[Sixtysixdeuce]

Bogda89 is right, a lot of older kits A) weren't built for modern brushless power & speed, and B) plastics become brittle with age.

If you want something fast to beat the hell out of, pick up an Arrma Kraton 6s EXB, Associated Rival MT8, E-Revo, etc.

Some of the vintage stuff can handle brushless alright, I've got a lot of vintage 1/10 Associated buggies and trucks and several converted 1/8 nitro buggies and truggies. But the old T-Maxx and E-maxx have 1/8 scale + weight with a lot of 1/10 part geometry, so they're not gonna take the torque like a beefy 1/8 critter or a 3.5 pound 2WD buggy or stadium truck that will mostly just spin tires.

1/10 short course truck electronics with moderate gearing, and use that is cognizant of the truck's age and weaker construction will allow you to enjoy it without destroying it.

Take it from someone who has overpowered a lot of vintage kits with both brushless motors and potent nitro engines.

There are definitely efficiency advantages to lipo/graphine and brushless if you select components that will more closely mimic the brushed motors. Some of my favorite vintage RC10 buggies and RC10T/T2 kits have fairly sedate 13.5T or 17.5T sensored brushless motors with ESC programming and gearing that is matched to the chassis, they're super smooth and controllable with long run times.