Senton I'm a Dummy. Bought a 3660 4200kv setup.. PLEASE HELP

[bigbristv]

So I went the route of buying a Senton 4X4 mega and then converting it to brushless which was my first foray into Arrma and LiPo batts and brushlessness so please be gentle.

I went with a 60a x 3650 x 3900kv x 23t pinion on the stock 91t spur, etc. Only mild cogging and it gets up close to 49mph with no major heat issues.

Fast forward to today, I get an 80a x 3660 x 4200kv setup and after a couple of very fast pulls stripped out the spur after only getting up to 47mph.

So now I'm looking at 32p gearing (stock BLX .8 mod) pinion & spur situation but I have questions and am hoping you can help:

1. The stock blx setup is 100a x 3200kv x 57t x 20t and from what I hear is pretty awesome on 3s out the box. Would it be bad to say bump the motor up to 4200kv?

2. Am I looking at potential heat issues and why have I not heard of anyone attempting this?

3. Is my thinking that going up to a 3660 can from 3650 to gain more torque wrong if I also increase the kv?

4. Why are people going bigger motor/lower kv and then gearing up? Heat?

What am I missing here?

Thanks

 

[ArrmaFreek2022]

So I went the route of buying a Senton 4X4 mega and then converting it to brushless which was my first foray into Arrma and LiPo batts and brushlessness so please be gentle.

I went with a 60a x 3650 x 3900kv x 23t pinion on the stock 91t spur, etc. Only mild cogging and it gets up close to 49mph with no major heat issues.

Fast forward to today, I get an 80a x 3660 x 4200kv setup and after a couple of very fast pulls stripped out the spur after only getting up to 47mph.

So now I'm looking at 32p gearing (stock BLX .8 mod) pinion & spur situation but I have questions and am hoping you can help:

1. The stock blx setup is 100a x 3200kv x 57t x 20t and from what I hear is pretty awesome on 3s out the box. Would it be bad to say bump the motor up to 4200kv?

2. Am I looking at potential heat issues and why have I not heard of anyone attempting this?

3. Is my thinking that going up to a 3660 can from 3650 to gain more torque wrong if I also increase the kv?

4. Why are people going bigger motor/lower kv and then gearing up? Heat?

What am I missing here?

Thanks

Firstly good for you for trying different things and experimenting, hope you're having fun. Secondly I'm not an expert...
Yes the 4200KV motor would have more heat as the motor is gonna spin more if that makes sense.
Going to the 3660 was a good move, the blx version of the trucks come with a 3660. Keeping the KV lower will usually result in lower temps plus you could then accomplish the same effect in a way by gearing up if you want to go faster on low KV. Getting a higher KV motor you will sometimes not be able to run on higher voltage so say a 4200KV motor at 12.6(3s full charge) would give you 52,920rpm which is probably above the recommended rpm. Voltage times kv gives you rpm, sorry if you knew that.

So by going bigger on the motor guys can gear up with lots of tourque and if need be they will gear up to get higher speeds, this while achieving lower temps. And Bigger motors means they can run higher voltages like 6s or 8s. Not on these 3s models of course. I'v run the 6s system on my 3s model with no issues. I'm light on the throttle thow. Thats just to give you ideas later lol.

If I messed up somewhere one of the guys will set you straight I'm sure, hope this helps.

 

[bigbristv]

Firstly good for you for trying different things and experimenting, hope you're having fun. Secondly I'm not an expert...
Yes the 4200KV motor would have more heat as the motor is gonna spin more if that makes sense.
Going to the 3660 was a good move, the blx version of the trucks come with a 3660. Keeping the KV lower will usually result in lower temps plus you could then accomplish the same effect in a way by gearing up if you want to go faster on low KV. Getting a higher KV motor you will sometimes not be able to run on higher voltage so say a 4200KV motor at 12.6(3s full charge) would give you 52,920rpm which is probably above the recommended rpm. Voltage times kv gives you rpm, sorry if you knew that.

So by going bigger on the motor guys can gear up with lots of tourque and if need be they will gear up to get higher speeds, this while achieving lower temps. And Bigger motors means they can run higher voltages like 6s or 8s. Not on these 3s models of course. I'v run the 6s system on my 3s model with no issues. I'm light on the throttle thow. Thats just to give you ideas later lol.

If I messed up somewhere one of the guys will set you straight I'm sure, hope this helps.

This makes perfect sense. Thanks for the fast reply,, I'm up watching videos and searching right now.

It's just I'm already running a 3900kv [3650] motor so I figured going up 300kv wouldn't be a big deal especially since it's a longer can.

 

[Bustedaw11]

I run a 4300 in one of my 4x4 trucks that was originally a 3600. I gotta be easier on gearing because of temps, so with that I wind up with an identically fast truck but with more temperamental temps I have to watch.

 

[Greengaunja]

No worries. Not sure if your model came with the heat sink or not, but if it did, mount 2 Rockets on it. If it didn't, check out PowerHobby's fan mounts.
Powerhobby Aluminum Motor Mount 30-40MM for Twister Fans (47-49MM) https://a.co/d/iLMQt5A
You want the 36-38mm

Firstly good for you for trying different things and experimenting, hope you're having fun. Secondly I'm not an expert...
Yes the 4200KV motor would have more heat as the motor is gonna spin more if that makes sense.
Going to the 3660 was a good move, the blx version of the trucks come with a 3660. Keeping the KV lower will usually result in lower temps plus you could then accomplish the same effect in a way by gearing up if you want to go faster on low KV. Getting a higher KV motor you will sometimes not be able to run on higher voltage so say a 4200KV motor at 12.6(3s full charge) would give you 52,920rpm which is probably above the recommended rpm. Voltage times kv gives you rpm, sorry if you knew that.

So by going bigger on the motor guys can gear up with lots of tourque and if need be they will gear up to get higher speeds, this while achieving lower temps. And Bigger motors means they can run higher voltages like 6s or 8s. Not on these 3s models of course. I'v run the 6s system on my 3s model with no issues. I'm light on the throttle thow. Thats just to give you ideas later lol.

If I messed up somewhere one of the guys will set you straight I'm sure, hope this helps.

What did you do to that model? When I ran 6s on my fully uograded 3s Senton, I broke sh!t left and right. Even destroyed my hardened steel spur and broke teeth off the rear steel ring gear and chipped the input gear. Also broke a chassis, more suspension arms than I care to remember. I think the only thing that held up were the HD drive axles. It was funny because the first several runs I wasn't breaking stuff.

 

[bigbristv]

I run a 4300 in one of my 4x4 trucks that was originally a 3600. I gotta be easier on gearing because of temps, so with that I wind up with an identically fast truck but with more temperamental temps I have to watch.

Interesting. Are you running MT tires on those rigs? Also, how far out from stock is your gearing?

No worries. Not sure if your model came with the heat sink or not, but if it did, mount 2 Rockets on it. If it didn't, check out PowerHobby's fan mounts.
Powerhobby Aluminum Motor Mount 30-40MM for Twister Fans (47-49MM) https://a.co/d/iLMQt5A
You want the 36-38mm
View attachment 329502

What did you do to that model? When I ran 6s on my fully uograded 3s Senton, I broke sh!t left and right. Even destroyed my hardened steel spur and broke teeth off the rear steel ring gear and chipped the input gear. Also broke a chassis, more suspension arms than I care to remember. I think the only thing that held up were the HD drive axles. It was funny because the several runs I wasn't breaking stuff.

So far I have moved up to a 23t pinion, added a surpass hobby 60a 3650 3900kv system, swapped out the receiver, added the center shaft bearing and a fan/heat sink on the motor. While the temp gun I use is my fingers, I haven't noticed any heat problems or LVC issues. And I run it hard, some evidence here:

and here:

I explain/show the mods in here:

Just ordered a metal 91t spur so I'll see how that goes but originally I wanted to build my own better BLX and now even moreso taking cues from the new 4s.

Oh, and remember me? The guy afraid of LiPo? I'm running it on 5200mah 80c 3s

 

[Greengaunja]

Oh, and remember me? The guy afraid of LiPo? I'm running it on 5200mah 80c 3s

Not sure I follow what you mean there. But my advice was based on concerns of overheating. Not necessarily my own as my 3S Senton(blx100/3060 3200kv) runs fine without fans or heatsink. Not only is my location(Ontario Canada) a factor, so are the times I usually head out(late evening/night).

 

[ArrmaFreek2022]

No worries. Not sure if your model came with the heat sink or not, but if it did, mount 2 Rockets on it. If it didn't, check out PowerHobby's fan mounts.
Powerhobby Aluminum Motor Mount 30-40MM for Twister Fans (47-49MM) https://a.co/d/iLMQt5A
You want the 36-38mm
View attachment 329502

What did you do to that model? When I ran 6s on my fully uograded 3s Senton, I broke sh!t left and right. Even destroyed my hardened steel spur and broke teeth off the rear steel ring gear and chipped the input gear. Also broke a chassis, more suspension arms than I care to remember. I think the only thing that held up were the HD drive axles. It was funny because the first several runs I wasn't breaking stuff.

I think you hit the nail on the head lol. At first you were probably being easy, then it really gets to be too much fun. When I saw that I put it back into a 6s, I'm sure a little longer I woulda been really hard on her. You have a lead finger my friend.

 

[bigbristv]

Not sure I follow what you mean there. But my advice was based on concerns of overheating. Not necessarily my own as my 3S Senton(blx100/3060 3200kv) runs fine without fans or heatsink. Not only is my location(Ontario Canada) a factor, so are the times I usually head out(late evening/night).

I like visual explanations ergo:

 

[bigbristv]

Update:
I took the seat-of-pants approach and like 10 Arrma SKUs and almost as many hours later I had replaced/rebuilt my rear diff, built the .8 mod slipper gearing, added a 20t pinion, installed and went ripping.

Got up over 46mph but the body catches air and flips over. With the body removed I got 56mph on an almost dead 3s batt. Nice!

Have a new body coming and then I think imma just take it easy. She's done well.

Then why did you order roof rails, bris?

[Shrugs]

 

[bigbristv]

Update and more help needed please:

I have a Senton Mega converted to a BLX and first went with a 3650 3900kv motor with a 60a esc combo which I still have but later put in a road car.

So I went up to a 3660 4200kv motor with an 80a esc. I was having very little to no issues with the first combo but I couldn't wheelie or hit 50mph.

The second combo stripped the mega pinion and rear diff so I switched up to the BLX setup for those items which changed gearing.

So now I was having more frequent thermal limp mode sessions so I decided to get a 120a esc. Burned it up, like desoldered batt connectors, purple smoke and all.

Replaced it with the same esc and I'm thinking it's going thermal (blinking light) but it hasn't measured over 100 degrees after a run and while blinking.

This led me to look at the mfg stated parameters for their escs and found between the 60a, 80a, 120a, 150a, each one recommends less than 4000kv, 3000kv, 2000kv etc. respectively.

I have a 3500kv motor coming tomorrow and was going to order a different brand 120a esc but should I just stick with the 60a? The recommended kv is around 3500-4000 for that one.

Sorry for the long read but I just want to run on 3s (5200mah 80c) and be able to wheelie on demand and run hard without having to keep waiting for the thermal shutdown to subside. What do I do?

 

[Neelis]

For a Senton on 3s with a 3500kv motor, you need a decent 120A ESC.

Doing wheelies depends on your punch settings, how tight you set the slipper clutch and the width of your tires.

This wheelies on demand:

I am running a Hobbywing Max10 120A ESC with a 3660 3200kv on my Typhon 3s and the only issue I have, is that with the second battery on full throttle, the ESC stops, because of the 3200kv motor overheating.
ESC is fine.

 

[bigbristv]

For a Senton on 3s with a 3500kv motor, you need a decent 120A ESC.

Doing wheelies depends on your punch settings, how tight you set the slipper clutch and the width of your tires.

This wheelies on demand:
View attachment 332137

I am running a Hobbywing Max10 120A ESC with a 3660 3200kv on my Typhon 3s and the only issue I have, is that with the second battery on full throttle, the ESC stops, because of the 3200kv motor overheating.
ESC is fine.

Interesting. So the esc will stop if the motor gets too hot?

 

[Neelis]

With this setup yes, it has a motor thermal protection.
Hobbywing Max10 120A SCT ESC.

 

[bigbristv]

With this setup yes, it has a motor thermal protection.
Hobbywing Max10 120A SCT ESC.

View attachment 332146View attachment 332147

Then I might have to pick one up, thanks. Was eyeing those but didn't want to have to solder