Esc kv limit

[Greywolf74]

@RC MAN
What RC car are you doing this with? The weight and size will play a big part in the motor sizing and ESC needs.
Realistically how fast do you want to see this car go?
Have you considered how you will record speeds yet? The GPS units run around $60-80. Don't put your cell phone on the car....

You can go cheap on motors like surpass or others, but the ESC is the biggest factor in going fast. Even factory motors from Arrma are not bad (See example below in credentials). The Arrma BLX185 esc or their new smart series will stop in the 94-98 mph range with metal chassis 1/8 scale cars. This number would be higher with a lighter 1/10 on-road car.

The limits of this ESC is due to amperage limiting. Amperage limiting exists on all HobbyWing ESCs or their re-branded models like the Arrma ESCs.

Credentials for my input:

I have been 130 with the Arrma Typhon on the stock blx2050 motor.
At one point I had the worlds fastest 2 cell Limitless at 86 mph. (using a TP4050 motor)
Now building an custom car for 200+ goals.

Pics of the new build:

Body mold:
View attachment 129520

Design in CAD
View attachment 129521
View attachment 129522

can't wait to see some running footage of that thing. Looks sick!

 

[RC MAN]

@RC MAN
What RC car are you doing this with? The weight and size will play a big part in the motor sizing and ESC needs.
Realistically how fast do you want to see this car go?
Have you considered how you will record speeds yet? The GPS units run around $60-80. Don't put your cell phone on the car....

You can go cheap on motors like surpass or others, but the ESC is the biggest factor in going fast. Even factory motors from Arrma are not bad (See example below in credentials). The Arrma BLX185 esc or their new smart series will stop in the 94-98 mph range with metal chassis 1/8 scale cars. This number would be higher with a lighter 1/10 on-road car.

The limits of this ESC is due to amperage limiting. Amperage limiting exists on all HobbyWing ESCs or their re-branded models like the Arrma ESCs.

Credentials for my input:

I have been 130 with the Arrma Typhon on the stock blx2050 motor.
At one point I had the worlds fastest 2 cell Limitless at 86 mph. (using a TP4050 motor)
Now building a custom car for 200+ goals.

Pics of the new build:

Body mold:
View attachment 129520

Design in CAD
View attachment 129521
View attachment 129522

I Am not too sure what vehicle i am going to use yet. I am thinking of a short course truck that wont really be over 4Kg. I am also trying to hit around the 127mph with the Tp 3630-cm 7000kv 3s with the Mamba Monster 2 and a 45t pinion and a 84t spur. Do you think i could go any faster with the Tp 3640 4700kv with the MM2 or would it be drawing too many amps for the MM2. The reason behind a short course Truck is because i also want to do some bashing with it as well so it is not JUST a speed build. And yes i Definitely NOT put my phone on it trying to record its top speed Anyway i don't think those apps even work anyway.


{Nice build BTW}

I'm not sure if it matters but the Tp brushless motors look to be made for RC airplanes which may or may not have a power band that is suitable for an RC vehicle. Also, have you checked that a 45T pinion gear will for sure fit in your RC vehicle?

The Tp motor i plan to use is for Rc cars.
And no i have not checked if the pinion will fit in the car but when i get it i will definitely check cuz a 45t pinion is MASSIVE

can't wait to see some running footage of that thing. Looks sick!

ME TOO

 

[Greywolf74]

I Am not too sure what vehicle i am going to use yet. I am thinking of a short course truck that wont really be over 4Kg. I am also trying to hit around the 127mph with the Tp 3630-cm 7000kv 3s with the Mamba Monster 2 and a 45t pinion and a 84t spur. Do you think i could go any faster with the Tp 3640 4700kv with the MM2 or would it be drawing too many amps for the MM2. The reason behind a short course Truck is because i also want to do some bashing with it as well so it is not JUST a speed build. And yes i Definitely NOT put my phone on it trying to record its top speed Anyway i don't think those apps even work anyway.

With a 7700kv motor you wont be able to bash it anywhere but a parking lot and even then you're going to have to go to a smaller pinion or its just going to overheat during a bash session.

The 4700kv will pull less amperage than a 7700kv on the same voltage.

And no i have not checked if the pinion will fit in the car but when i get it i will definitely check cuz a 45t pinion is MASSIVE

You can usually mod the motor mount with a dremel to get bigger pinions to fit although sometimes you'll need to buy an after market motor mount to be able to mod it depending on how the factory one is designed.

 

[LibertyMKiii]

I Am not too sure what vehicle i am going to use yet. I am thinking of a short course truck that wont really be over 4Kg. I am also trying to hit around the 127mph with the Tp 3630-cm 7000kv 3s with the Mamba Monster 2 and a 45t pinion and a 84t spur. Do you think i could go any faster with the Tp 3640 4700kv with the MM2 or would it be drawing too many amps for the MM2. The reason behind a short course Truck is because i also want to do some bashing with it as well so it is not JUST a speed build. And yes i Definitely NOT put my phone on it trying to record its top speed Anyway i don't think those apps even work anyway.

One of the biggest things regarding brushless motors and going over 100 mph is torque! The air is pushing hard on the car and the motor needs to power through that with torque. The motor torque is significantly stronger with larger diameter motors. For this reason, anyone going over 100 mph is using 40mm or the 1/5 scale motors (56mm and 58mm). You also increase the torque with longer motors, but I have found diameter seems to produce more torque.

3s is very limiting in regards to power. Also it is worth knowing that higher kv pulls more amps. I know all the top names in speed running and no one runs 7000 kv except for maybe a very light weight on-road car running 2s, or drag cars, which rarely see speeds over 110mph. High KV motors get very hot, very quickly!

A quick note in math for how this all works.
voltage x amps = watts

11.1 v * 300 amps = 3,300 watts
watts / 745.69 = hp

3300 watts / 745.69 = 4.4 hp

If you were to instead run 6s on an Arrma 6s vehicle with an ESC that can output 300+ amps (factory RTR ESCs are generally 100a to 150a)

22.2v * 300 amps = 6,600 watts
6,600 watts / 745.69 = 8.85 hp

I honestly think you should get the MMX8s esc and an Arrma BLX2050kv motor or the new Spektrum 2050kv motor. Having data logs from the MMX8s to help you make well educated decisions on what changes to make to the car will be priceless. Without that data you are simply guessing. MM2 esc does not have data logs by the way. Don't bother with the MMX6s esc as it runs hot and has thermal shutdown kicking in all the time.

One thing I can say is that you can spend a small fortune making a SCT like the Slash 4x4 into a speed car. It is far cheaper to start out with an Arrma 6s vehicle. The other thing worth noting is that short wheelbase cars are very unstable at high speeds. Cars like the typhon and SCT vehicles. Your best money spent for going fast would be something with a longer wheelbase like a Kraton, Talion, Limitless, Infraction....

The Arrma cars have a very solid spring/shock setup, heavy duty double a-arms. Aluminum chassis for reduced flex.
Also differentials are a consideration. Some brands differentials just don't hold the power. Hobao is another solid option for speed use.

Having a dual purpose RC car just does not work. It would have completely different suspension, tires, gearing, aerodynamics. They are best left as two separate RC cars.

 

[RC MAN]

With a 7700kv motor you wont be able to bash it anywhere but a parking lot and even then you're going to have to go to a smaller pinion or its just going to overheat during a bash session.

The 4700kv will pull less amperage than a 7700kv on the same voltage.

yes if i was going to bash it i would change the gearing dramatically so it doesn’t over heat.

And on TP’s website they say the 3640 4700kv will pull a max amps of 215 but the 3630-cm 7000kv will only pull 147 amps and my battery pack can only give 250 amps continuously so that was holding me back from getting the 4700kv and a few other things like the 7000kv one is $50 more expensive and 10 grams more than the 4700kv. would anyone know why the 7000kv one is more expensive and is ten grams heavier than the 4700kv one which is 10mm longer?I guess the biggest question is which one will make me go faster?

One of the biggest things regarding brushless motors and going over 100 mph is torque! The air is pushing hard on the car and the motor needs to power through that with torque. The motor torque is significantly stronger with larger diameter motors. For this reason, anyone going over 100 mph is using 40mm or the 1/5 scale motors (56mm and 58mm). You also increase the torque with longer motors, but I have found diameter seems to produce more torque.

3s is very limiting in regards to power. Also it is worth knowing that higher kv pulls more amps. I know all the top names in speed running and no one runs 7000 kv except for maybe a very light weight on-road car running 2s, or drag cars, which rarely see speeds over 110mph. High KV motors get very hot, very quickly!

A quick note in math for how this all works.
voltage x amps = watts

11.1 v * 300 amps = 3,300 watts
watts / 745.69 = hp

3300 watts / 745.69 = 4.4 hp

If you were to instead run 6s on an Arrma 6s vehicle with an ESC that can output 300+ amps (factory RTR ESCs are generally 100a to 150a)

22.2v * 300 amps = 6,600 watts
6,600 watts / 745.69 = 8.85 hp

I honestly think you should get the MMX8s esc and an Arrma BLX2050kv motor or the new Spektrum 2050kv motor. Having data logs from the MMX8s to help you make well educated decisions on what changes to make to the car will be priceless. Without that data you are simply guessing. MM2 esc does not have data logs by the way. Don't bother with the MMX6s esc as it runs hot and has thermal shutdown kicking in all the time.

One thing I can say is that you can spend a small fortune making a SCT like the Slash 4x4 into a speed car. It is far cheaper to start out with an Arrma 6s vehicle. The other thing worth noting is that short wheelbase cars are very unstable at high speeds. Cars like the typhon and SCT vehicles. Your best money spent for going fast would be something with a longer wheelbase like a Kraton, Talion, Limitless, Infraction....

The Arrma cars have a very solid spring/shock setup, heavy duty double a-arms. Aluminum chassis for reduced flex.
Also differentials are a consideration. Some brands differentials just don't hold the power. Hobao is another solid option for speed use.

Having a dual purpose RC car just does not work. It would have completely different suspension, tires, gearing, aerodynamics. They are best left as two separate RC cars.

thanks you for the information

So i can’t go past the width 36mm or i would but i can go longer in length. I can’t also go past 3s. So are you saying a 3660 can size won’t have enough torque on 3s to get me past 100mph? or should i get the 4700kv one instead. The only reason i want to get the 7000kv is because on a speed calculator it said i would get much higher speed with the 7000kv one vs the 4700kv one on the same gearing. And i don’t want to go so extreme on the gearing that i have to have custom motor mounts and other crap like that so the biggest pinion i can fit is a 45t pinion and the smallest spur i can do is a 84t and if i can run the 7000kv one on that gearing then it will smash the 4700kv in speed.

 

[Greywolf74]

yes if i was going to bash it i would change the gearing dramatically so it doesn’t over heat.

And on TP’s website they say the 3640 4700kv will pull a max amps of 215 but the 3630-cm 7000kv will only pull 147 amps and my battery pack can only give 250 amps continuously so that was holding me back from getting the 4700kv and a few other things like the 7000kv one is $50 more expensive and 10 grams more than the 4700kv. would anyone know why the 7000kv one is more expensive and is ten grams heavier than the 4700kv one which is 10mm longer?I guess the biggest question is which one will make me go faster?

thanks you for the information

So i can’t go past the width 36mm or i would but i can go longer in length. I can’t also go past 3s. So are you saying a 3660 can size won’t have enough torque on 3s to get me past 100mph? or should i get the 4700kv one instead. The only reason i want to get the 7000kv is because on a speed calculator it said i would get much higher speed with the 7000kv one vs the 4700kv one on the same gearing. And i don’t want to go so extreme on the gearing that i have to have custom motor mounts and other crap like that so the biggest pinion i can fit is a 45t pinion and the smallest spur i can do is a 84t and if i can run the 7000kv one on that gearing then it will smash the 4700kv in speed.

The 7000kv is going to overheat anywhere but on pavement regardless of gearing. If your kit is more than 6-8lbs it will prolly overheat even just bashing it in a parking lot. Its not meant for offload use. Its definitely gonna get hot quickly doing speed runs.

More often than not you can't compare one manufacturers specs with another manufacturer because they all have different ways of testing and they all have different levels of truth in their specs that they do list. The 7000kv is going to pull more amps than the 4700kv. An MM2 or MMX8 are gonna be able to run any 1/10 scale motor, especially a mid to low kv motor.

 

[RC MAN]

The 7000kv is going to overheat anywhere but on pavement regardless of gearing. If your kit is more than 6-8lbs it will prolly overheat even just bashing it in a parking lot. Its not meant for offload use. Its definitely gonna get hot quickly doing speed runs.

More often than not you can't compare one manufacturers specs with another manufacturer because they all have different ways of testing and they all have different levels of truth in their specs that they do list. The 7000kv is going to pull more amps than the 4700kv. An MM2 or MMX8 are gonna be able to run any 1/10 scale motor, especially a mid to low kv motor.

so in other word you would recommend getting the 4700kv one over the 7000kv because i can bash with it, it will get less hot and i will get more speed with the 4700kv one?

 

[Greywolf74]

so in other word you would recommend getting the 4700kv one over the 7000kv because i can bash with it, it will get less hot and i will get more speed with the 4700kv one?

IDK which one will end up being faster (a lot of it is going to depend on usable gearing and how heavy the car is) but the 7000kv is going to get real hot real quick and is generally not suited for off road use. Its really only meant for light weight 1/10 scale on road kits. If you want something that going to have the potential to go pretty fast and be usable off road the 4700kv is a better choice for trying to do both. That being said its not practical to do both. Trying to do both you're gonna end up with a kit that can technically do both but wont be ideal for either one.

 

[RC MAN]

IDK which one will end up being faster (a lot of it is going to depend on usable gearing and how heavy the car is) but the 7000kv is going to get real hot real quick and is generally not suited for off road use. Its really only meant for light weight 1/10 scale on road kits. If you want something that going to have the potential to go pretty fast and be usable off road the 4700kv is a better choice for trying to do both. That being said its not practical to do both. Trying to do both you're gonna end up with a kit that can technically do both but wont be ideal for either one.

thanks for the reply

I am also thinking of running a Tp 3650 3800kv in it with a mamba monster x 8s. Would that be a good combo for speed and bashing? Also (i am a bit confused by this) but would i be able to run the Tp 3650 on 4s because it says on Tp’s website that the maximum voltage for it is 15.6 so that is closer to 4s then 3s but the same next kv down motor is the 3000kv one which says it can only be run on 13 volts and has a max amps around 300 and the Tp 3650 3800kv one has 420 max amps!!!!!!!!!!!!!!!!! since the 3000kv one has a lower kv shouldn’t that mean it can be run on a higher voltage than the 3800kv one?????
Also their watts of power and the max volts of the Tp 3800kv don’t add up either because they say the max rpm of the 3800kv is 68k and if you divide 68k by 3800 you get around 17 volts you could run it on. And if you get the max amps which is 420 for the 3800kv and times it by 17 you get 7140 max watts of power vs the 4500 watts they claim on their website! even if you times 420 by 15.6 volts they say you still get 6552 watts of power which is still way more than the 4500 watts they say! so they have either got their volts wrong (which i think is much most likely, a second opinion to that would be good) or they got their max amps wrong (which is not very likely, again a second opinion on that and everything else i said we be very helpful!)

Any help with this madness would be much appreciated

 

[Greywolf74]

thanks for the reply

I am also thinking of running a Tp 3650 3800kv in it with a mamba monster x 8s. Would that be a good combo for speed and bashing? Also (i am a bit confused by this) but would i be able to run the Tp 3650 on 4s because it says on Tp’s website that the maximum voltage for it is 15.6 so that is closer to 4s then 3s

A fully charged 4S lipo is 16.8V which exceeds the maximum rating for the 3840kv motor. You could probably run it on 4s but youd have to go with really tall gearing and even then its gonna get hot really quickly.

but the same next kv down motor is the 3000kv one which says it can only be run on 13 volts and has a max amps around 300 and the Tp 3650 3800kv one has 420 max amps!!!!!!!!!!!!!!!!! since the 3000kv one has a lower kv shouldn’t that mean it can be run on a higher voltage than the 3800kv one?????

Not necessarily. Depends on how the motor is made.

Also their watts of power and the max volts of the Tp 3800kv don’t add up either because they say the max rpm of the 3800kv is 68k and if you divide 68k by 3800 you get around 17 volts you could run it on.

The max RPM for the 3650 3840kv motor is 58k not 68k. 58,000/3840kv = 15.10416 volts. Their website says 15.6V max.

And if you get the max amps which is 420 for the 3800kv and times it by 17 you get 7140 max watts of power vs the 4500 watts they claim on their website! even if you times 420 by 15.6 volts they say you still get 6552 watts of power which is still way more than the 4500 watts they say! so they have either got their volts wrong

The max voltage and max amperage dont total the max Wattage. Not sure why. Youd have to ask the company on that one.

(which i think is much most likely, a second opinion to that would be good) or they got their max amps wrong (which is not very likely, again a second opinion on that and everything else i said we be very helpful!)

I'm guessing theres some kind of technical information that the company knows that we dont.

 

[Pat_ranch]

You're overthinking it, man.

You've gotten some top shelf advice from a couple guys who know their (not putting my own name into that mix, by the way). They've already done the work on this. Reinventing the wheel ain't cost-effective. You should try their advice and get some trigger time in with the build. After about the third time you have to reglue a different pinion grub, and readjust your mesh, you'll give up on the idea of a dual purpose rig. Grub screws are a pain in the .

I started with stock everything, and pinioned up. Then I built a spur. I'll work up through a couple pinions until I find my sweet spot. For my speed rig, that'll be the end of it. It only needs to break 100, and I'm 3mph away from that right now. If I need to go faster I'll build and infraction or limitless based on one of the build logs in the speed freak subforum of the arrma forum. Study some of the builds on the link below.

I hope @WoodiE is OK with me putting this link here-

https://www.arrmaforum.com/forums/speed-demons.63/

 

[RC MAN]

A fully charged 4S lipo is 16.8V which exceeds the maximum rating for the 3840kv motor. You could probably run it on 4s but youd have to go with really tall gearing and even then its gonna get hot really quickly.

Not necessarily. Depends on how the motor is made.

The max RPM for the 3650 3840kv motor is 58k not 68k. 58,000/3840kv = 15.10416 volts. Their website says 15.6V max.

Would tall gearing for that motor be like a 45t pinion and a 72t or 84t spur? because it is a very long motor 84mm long so i would have thought even on 4s and that gearing it would be alright?

 

[Greywolf74]

Would tall gearing for that motor be like a 45t pinion and a 72t or 84t spur? because it is a very long motor 84mm long so i would have thought even on 4s and that gearing it would be alright?

If I were going to try and run that motor on 4S (and I wouldnt) then Id start with an 84T spur and about an 18T pinion and see if theres room for a bigger pinion or if you still need to go smaller.

 

[RC MAN]

What about it on 3s? would the 45t pinion and 72t/84t spur be good with the Tp 3650 3840kv

Also would the Mamba Monster x 8s be a good esc for it?

 

[Greywolf74]

What about it on 3s? would the 45t pinion and 72t/84t spur be good with the Tp 3650 3840kv

Also would the Mamba Monster x 8s be a good esc for it?

Hard to say man. Gearing is a type of tuning you have to do with any kit. Start with 45/84 and see how your temps do and then you can adjust gearing according to how hot or cool the motor and ESC are running.

If you want the data-logging feature of the MMX8 then Id say sure but if you dont care about data-logging then save yourself some money and get the MM2.

 

[LibertyMKiii]

yes if i was going to bash it i would change the gearing dramatically so it doesn’t over heat.

And on TP’s website they say the 3640 4700kv will pull a max amps of 215 but the 3630-cm 7000kv will only pull 147 amps and my battery pack can only give 250 amps continuously so that was holding me back from getting the 4700kv and a few other things like the 7000kv one is $50 more expensive and 10 grams more than the 4700kv. would anyone know why the 7000kv one is more expensive and is ten grams heavier than the 4700kv one which is 10mm longer?I guess the biggest question is which one will make me go faster?

thanks you for the information

So i can’t go past the width 36mm or i would but i can go longer in length. I can’t also go past 3s. So are you saying a 3660 can size won’t have enough torque on 3s to get me past 100mph? or should i get the 4700kv one instead. The only reason i want to get the 7000kv is because on a speed calculator it said i would get much higher speed with the 7000kv one vs the 4700kv one on the same gearing. And i don’t want to go so extreme on the gearing that i have to have custom motor mounts and other crap like that so the biggest pinion i can fit is a 45t pinion and the smallest spur i can do is a 84t and if i can run the 7000kv one on that gearing then it will smash the 4700kv in speed.

Which RC vehicle are we talking about? Any that can support running 100mph usually can also run a 40mm motor.

Just remember you can go cheap on the front end on the RC vehicle and then put $500 in metal parts to make it hold the power to go over 100mph or you can buy a used Arrma 6s model up front and save $100s.

Motor Amp ratings can be taken as a grain of salt. Those are voltage and amperage ratings for 10 secs use.
For speed runs I have routinely put 2x the amps through the motor from what TP Power rates them at. For example a motor rated at 220a I put over 450a through it for short 6-7 second speed runs.

thanks for the reply

I am also thinking of running a Tp 3650 3800kv in it with a mamba monster x 8s. Would that be a good combo for speed and bashing? Also (i am a bit confused by this) but would i be able to run the Tp 3650 on 4s because it says on Tp’s website that the maximum voltage for it is 15.6 so that is closer to 4s then 3s but the same next kv down motor is the 3000kv one which says it can only be run on 13 volts and has a max amps around 300 and the Tp 3650 3800kv one has 420 max amps!!!!!!!!!!!!!!!!! since the 3000kv one has a lower kv shouldn’t that mean it can be run on a higher voltage than the 3800kv one?????
Also their watts of power and the max volts of the Tp 3800kv don’t add up either because they say the max rpm of the 3800kv is 68k and if you divide 68k by 3800 you get around 17 volts you could run it on. And if you get the max amps which is 420 for the 3800kv and times it by 17 you get 7140 max watts of power vs the 4500 watts they claim on their website! even if you times 420 by 15.6 volts they say you still get 6552 watts of power which is still way more than the 4500 watts they say! so they have either got their volts wrong (which i think is much most likely, a second opinion to that would be good) or they got their max amps wrong (which is not very likely, again a second opinion on that and everything else i said we be very helpful!)

Any help with this madness would be much appreciated

Max voltage on the motor is rated to save their butts from you over revving the motor and blowing it up.

Voltage x KV = rpm. So if a motor can only handle 60k rpm and its rated at 3800kv
60,000 / 3800 = 15.7

Lower the KV value and you can run higher voltage to make that peak rpm value.

You can put 34v in that motor if you want, but just don't let and axle break or tires go up in the air where it can max out its potential rpms.
The CM series TP Power motors can pull more rpms because they have a metal sleeve over the rotor instead of Kevlar wrapping.

Lower the KV = more torque, this will allow for bigger gearing
Larger diameter motor = more torque for larger gearing
Longer motor = more torque for larger gearing.

 

[RC MAN]

Max voltage on the motor is rated to save their butts from you over revving the motor and blowing it up.

Voltage x KV = rpm. So if a motor can only handle 60k rpm and its rated at 3800kv
60,000 / 3800 = 15.7

Lower the KV value and you can run higher voltage to make that peak rpm value.

You can put 34v in that motor if you want, but just don't let and axle break or tires go up in the air where it can max out its potential rpms.
The CM series TP Power motors can pull more rpms because they have a metal sleeve over the rotor instead of Kevlar wrapping.

Lower the KV = more torque, this will allow for bigger gearing
Larger diameter motor = more torque for larger gearing
Longer motor = more torque for larger gearing.

So since i also want to do some bashing with the rig. I don't really think i want the Tp 3630 7700kv any more because it will probably over heat really quickly so i want to choose from these options.

3630 4700kv on 3s

3640 4700kv on 3s

3650 3840kv on 3s [probably]

3650 3080kv on 4s [probably]

so which one out of them do you think will give me the most speed and best bashing capabilities. I think i will probably go with the 3650 3080kv because according to a speed calculator on the same gearing the 3650 3080kv is about 10kmh faster than the 3650 3840kv on 4s [which i think i can probably run it on but acording to thier website it can only run on 13 volts but if you divide the max rpm 58k by the kv 3040 you get 18.8 so i can probably run it on 4s but just to clarify i have emailed the company] And it will have more torque on 4s so i could probably gear it up even more and make it go even faster.

 

[LibertyMKiii]

So since i also want to do some bashing with the rig. I don't really think i want the Tp 3630 7700kv any more because it will probably over heat really quickly so i want to choose from these options.

3630 4700kv on 3s

3640 4700kv on 3s

3650 3840kv on 3s [probably]

3650 3080kv on 4s [probably]

so which one out of them do you think will give me the most speed and best bashing capabilities. I think i will probably go with the 3650 3080kv because according to a speed calculator on the same gearing the 3650 3080kv is about 10kmh faster than the 3650 3840kv on 4s [which i think i can probably run it on but acording to thier website it can only run on 13 volts but if you divide the max rpm 58k by the kv 3040 you get 18.8 so i can probably run it on 4s but just to clarify i have emailed the company] And it will have more torque on 4s so i could probably gear it up even more and make it go even faster.

3650 would be my choice.
Lower KV will always run cooler and pull less amps until you gear up.

Plus the longer motor can will dissipate more heat and generate motor torque.

Still unsure what RC you are putting this in and why you want an 36mm motor vs a 40mm.

 

[Greywolf74]

So since i also want to do some bashing with the rig. I don't really think i want the Tp 3630 7700kv any more because it will probably over heat really quickly so i want to choose from these options.

3630 4700kv on 3s

3640 4700kv on 3s

3650 3840kv on 3s [probably]

3650 3080kv on 4s [probably]

so which one out of them do you think will give me the most speed and best bashing capabilities. I think i will probably go with the 3650 3080kv because according to a speed calculator on the same gearing the 3650 3080kv is about 10kmh faster than the 3650 3840kv on 4s [which i think i can probably run it on but acording to thier website it can only run on 13 volts but if you divide the max rpm 58k by the kv 3040 you get 18.8 so i can probably run it on 4s but just to clarify i have emailed the company] And it will have more torque on 4s so i could probably gear it up even more and make it go even faster.

Unless the company comes back and says that the 13V limit is a typo then Id get the 3840kv and run it on 3S and adjust gearing between bashing and speed runs. The max RPMs isnt the only thing that limits motor voltage. The construction of the motor in general, including but not limited to, the winds also dictate electrical characteristics of the motors too.

 

[RC MAN]

Unless the company comes back and says that the 13V limit is a typo then Id get the 3840kv and run it on 3S and adjust gearing between bashing and speed runs. The max RPMs isnt the only thing that limits motor voltage. The construction of the motor in general, including but not limited to, the winds also dictate electrical characteristics of the motors too.

yeah i probably would do that if they didn’t come back to me but they did and they said it was a typo and they changed the max voltage of the Tp 3650 3080kv to 19 volts so 4s. So i think i will probably go with the 3650 3080kv because according to a speed calculator on the same gearing the 3650 3080kv is about 10kmh faster than the 3650 3840kv on 4s and it will have more torque because it is on 4s so more bashing and better speed running potential. Also i calculated the max watts (According to my calculations Tps max watts are wayyyy of by 1000 to 1500 watts if their max amps are right but i can’t be bothered to chase it up with them because it ain’t gonna change anything.)
and it should have around 500 watts more power on 4s than the Tp 3650 3840kv on 3s. Also does more watts equal more torque or more horsepower?

Still unsure what RC you are putting this in and why you want an 36mm motor vs a 40mm.

well it is because i plan to put it in this RC car that comes with a 550 sized brushed motor so i assumed i can’t go any more in width. plus i am going to run a sensorless system (because i don’t think the TP 3650 3080kv is sensored) i don’t want any start up hesitation so it is about the biggest motor you can get with probably no to hardly any start up hesitation because i am pretty sure the wider the can the more start up hesitation you have. (also weight is starting to become a problem so i don’t really want a heavier motor)

Hard to say man. Gearing is a type of tuning you have to do with any kit. Start with 45/84 and see how your temps do and then you can adjust gearing according to how hot or cool the motor and ESC are running.

If you want the data-logging feature of the MMX8 then Id say sure but if you dont care about data-logging then save yourself some money and get the MM2.

Thanks for the advice with the gearing

It would be nice having data logging features and there is a few other really good features that isn’t on the mm2 and it fits the budget and i would imagine it will be able to handle more amps so less heat and more life and more motor performance.

also would any one be able to recommend a good big-ass high voltage fan that would be good with the Tp 3650 3080kv that could plug right in to my spektrum receiver