fit out a 2wd slash?

[j0e]

fit out a 2wd slash? UPDATED 10/5/20 w/ new gear!

In my collection of parts and electronics I found a Tenergy TrackStar 80A esc and 4000kv motor that I've been saving for something.

I figured this would be great for a 2wd slash with lcg chassis that my son could drive relatively fast (not too fast; he's 9).


My problem is that the motor and esc overheat before draining an entire battery.
I'm kind of lost on my gearing and have tried a few different combos and not sure where to go next.
I started with 90t spur and 17t pinion, then 90/19 and now 86/23.
Everything runs hot, like 160* plus and I'm not sure if I should be trying to bring my gear ratio down or up now?!?


Also, now my esc won't calibrate and I can't seem to find any good info as this unit seems to be disco'd.
So... I'm thinking of swapping in a vxl esc that I have or buying a sidewinder 3, 4 or a HobbyWing 10BL60.


Any input, ideas or suggestions are appreciated!
"thumbsup"

 

[Gula]

Does everything spin smoothly? How big are your tires? Bearings oiled? The esc you mentioned would work fine for your intent.

 

[MaX-D]

Go 86/19 on the gearing. It will bring the heat down a bit.

Sent from my LM-G710VM using Tapatalk

 

[j0e]

Does everything spin smoothly? How big are your tires? Bearings oiled? The esc you mentioned would work fine for your intent.

Everything seems to spin just fine.
Current tires are 2.2 Masher 2000's, but I've got some 3.5" street tires on 2.8 wheels coming.
That should lower my tire height by almost an inch.

Go 86/19 on the gearing. It will bring the heat down a bit.

That's what I thought; i need to "gear up" to lower my gear ratio.
:roll:

 

[Steve g]

Was it over heating on the 17/90? You geared up from there, which would increase speed and heat. Go back to 17/90, or even 15/90 if it fits. What kind of temps are you hitting?
Another option, which i did with my son's truck, is get a remote that can limit the throttle. Got his set to 75%, which it is almost as fast as 100, but it runs much cooler and the battery last noticeably longer.

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[j0e]

I need to do some more testing this weekend.
It was running hot and shutting down with all the gearing changes.
I’m going to swap the esc, run it some more and take temps this time.
Thanks for the help so far!
"thumbsup"

 

[j0e]

So, we got a little time to run this and it’s still finicky.
I put in a vxl esc and ran with the 23/86 gears.
It runs and it’s fast, but I get this weird cogging at full throttle.
I’ve never had that happen before; usually I get cogging at start ups.
With this, if I pull the trigger upto about 75% it runs great.
If I go farther, the clogging starts.
Also, when done for the day the motor was up to 198*!
Maybe my issues are motor. I may have cooked it.

 

[MaX-D]

So, we got a little time to run this and it’s still finicky.

I put in a vxl esc and ran with the 23/86 gears.

It runs and it’s fast, but I get this weird clogging at full throttle.

I’ve never had that happen before; usually I get clogging at start ups.

With this, if I pull the trigger upto about 75% it runs great.

If I go farther, the clogging starts.

Also, when done for the day the motor was up to 198*!

Maybe my issues are motor. I may have cooked it.

Gear down to 86 / 19 and it won't run so hot.

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[j0e]

Great. Any ideas on the cogging?
I’m kind of baffled.

 

[Steve g]

Could be over geared with a motor on its way out. Repeatedly over heating it would cause the magnets to get weaker and weaker, also causing the motor to run hotter faster. Should have geared it back down before you tried the new esc.
What batteries are you using?

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[j0e]

Batteries are 2s and 25-30c.
To gear “down” I need a smaller pinion and/or bigger spur, right?
If the motor is shot, I’ve got a 5700kv and another 4000kv I can swap in.
I think I might buy a new esc, too.

 

[durok]

I'm not certain you're clear on the best thing to do for an overheating motor...

Either run a bigger spur and the same pinion, or run a smaller pinion and the same spur.

The bigger the difference there is between the tooth count on your spur and pinion, the cooler your electronics will run.

Obviously you will lose some top speed if you do this, so experiment until you reach a gear combo that provides decent performance yet doesn't overheat.

A side benefit to gearing for a cooler motor is that what you lose on the top end, you will gain on the lower end - TORQUE FTW!!!

 

[meatmonkey]

Those mashed 2ks are great bashing tires, but they are much larger/heavier than the stock sc tires. This requires that you gear down to compensate. I'm not familiar with your particular motor, but some of the cheaper units basically use 380 guts in a 540 can to keep costs down. This also reduces torque, which requires further gearing down.

I'd start at 15/90 and it will still likely be to fast for most kids.

If you really cooked the motor it weakens the magnets and it will never make full power efficiency again.

Oftentimes clogging at full throttle once moving is a sign of weak batteries that can't supply enough amps to keep the esc happy. What brand batteries are you running, and how old/how many cycles on them?

 

[j0e]

Thanks for the info, fellas.
I think my issue is that I’m fighting multiple gremlins at once.
Now that I have a good starting spot for gearing I can work my way up or down.
I’m gonna pull the motor, too.

Is there a way to tell if it’s hurt?

 

[j0e]

...The bigger the difference there is between the tooth count on your spur and pinion, the cooler your electronics will run...

This is the part I always forget and need clarification on.

...some of the cheaper units basically use 380 guts in a 540 can to keep costs down. This also reduces torque, which requires further gearing down...

...Oftentimes cogging at full throttle once moving is a sign of weak batteries that can't supply enough amps to keep the esc happy. What brand batteries are you running, and how old/how many cycles on them?

The motor appears to be a true 540, not a 380 in a 540 can.


Batteries are Zippy and Turnigy 25c and 30c 4000+mah
I've been using these brands for years with good luck.
I did run a few of my older packs; I'll make sure to due further testing with my new packs that are new with 3 cycles or less.

...get a remote that can limit the throttle...

We're using a Spektrum DX5 Rugged, so throttle adjustments are available.
"thumbsup"

 

[j0e]

Man, idk what’s going on. I’ve got the worst luck or something.
Motor seems to be shot and esc is goofy.
I took a working vxl/5800 combo and swapped into this rig and now I can’t get reverse to work.
The esc keeps blinking the red low voltage light, too, even with fully charged cells.
:ror:

 

[j0e]

Well, I took the “easy” way out...
Ordered a new HobbyWing Max10 esc and 4000kv 4 pole motor.
If this doesn’t fix my issues it’s all going in the trash! Lol

 

[Shinchu]

Trash?! Man at least toss it up on the classifieds here.
I jave a slash 2wd and its brushed. Stock tires nothing done to it and it RIPS even oh NIMH batts.
I cant wait to see what it does with a nice punchy 50c 2S Lipo...

Your brushless combo is brave for a 9 year old lol but my son started with a barrage on 2s when he was 8... Mostly because he crashed his grandpas yeti at full rip on 3s with a castle 1406... Right into a boulder.
Whiskey throttle he panicked and squeezed harder.
But now hes 12 and wheeling an ascender with a blazer cab hard body and loves it. Saidbthe fast stuff is not his speed.

Anyway sounds like you are taking the right approach with new gear. I let some magic smoke out of the hobbywing 1060 in my kyosho outlaw rampage pro and its never been the same. No brakes and trying them only makes it go faster. Scary...

Let us know how your slash does with the new setup!

 

[j0e]

Trash?! Man at least toss it up on the classifieds here...

...Your brushless combo is brave for a 9 year old lol...

...Anyway sounds like you are taking the right approach with new gear...

hahaha! It won't really go to the trash.
I'm just getting frustrated with things not working; especially when they were before going in the slash.

My boy and I did get a few decent runs with the original 4000kv motor and it was pretty fast.
My son has been bashing rc's with me for years, so i think he can handle it.
We have two TXT's, one running a 4600 and the other with a 3800 and a wheely king with a 4000 in it.
I just took my 5800 and vxl out of a custom truck with wk axles.
That's where I got the vxl to put in the slash; it was working fine before the move.

What I think happened is I cooked the TrackStar motor and then it shorted out the TrackStar esc and the VXL esc.
On the last test with the 4000kv motor and vxl I noticed that the esc wires were HOT!
I also lost reverse and brakes with both escs; the trackstar would accelerate when brakes were applied!

I've never had that happen before and I didn't know the motor could hurt the esc, but I think it did.
:shock:

 

[j0e]

Received my new esc and motor... awesome!
The esc is programmable with the HW card, but the number prompts don’t line up.
Still, this combo is great.

We’re running 2.8 Banditos now and I started with 90/17 gearing.
As it is we achieved 26 mph and a max temp of 106* on the motor with 78* at the esc.
My 9 year old is happy now!
"thumbsup"