Uprated ESC for Clod

[Apollo11 19]

Before anyone says anything, I will admit that in hindsight this wasn't the smartest of moves. But the thing is that in a fit of youthful exuberance (doesn't happen often) I decided to get the fastest brushed Tamiya motors I could find. So I ordered two Super Stock BZs. Stupidly I didn't check against the spec of the ESC first. Now that one has arrived (two different suppliers as they were low on stock), I see it is 23T. The standard ESC that came with the Clod is rated for motors over 25T. Other than uprated bearings, the Clod is currently as standard. This leaves me with two fundamental questions:

1. How serious a problem is this? (i.e. how much damage would it do to the ESC? Is this far too much motor for the Clod?)

2. What are my options?

[Apollo11 19]

Assuming these motors will be ok in my Clod, would this be a suitable ESC for them?

https://www.modelsport.co.uk/hobbywing-quicrun-0880-dual-motor-brushed-esc-80a-waterproof/rc-car-products/440053

[wolfdogstinkus 1893]

That ESC is well recommended, a better upgrade would be the ESC and a 3s lipo.

A very noticeable power upgrade. 

Some say that the sports tuned motors have advanced timing which will mean the motor running in reverse will be slower which will cause running issues as one axles pushes or pulls the other one. 

Check motor timing and set it to zero if possible, or equal opposites to achieve the same speed in each direction.

[Apollo11 19]

So that would work then? And not put too much strain on the transmission and the like? I'm happy to stick with Nimh, at least for the time being.

At the risk of asking a bone question, what is this advanced timing? I've read it mentioned before, but don't understand what it is. I think I get what you're referring to re: one axle pushing/pulling the other: if the two motors aren't in sync, then one would be running faster than the other.

[MadInventor 3884]

6 minutes ago, wolfdogstinkus said:

That ESC is well recommended, a better upgrade would be the ESC and a 3s lipo.

A very noticeable power upgrade. 

Some say that the sports tuned motors have advanced timing which will mean the motor running in reverse will be slower which will cause running issues as one axles pushes or pulls the other one. 

Check motor timing and set it to zero if possible, or equal opposites to achieve the same speed in each direction.

This is what I've done with my clod. I believe that ESC is actually good for 4S on silver cans

 

[Apollo11 19]

2 minutes ago, MadInventor said:

This is what I've done with my clod. I believe that ESC is actually good for 4S on silver cans

 

Just that ESC, or the motors as well? What do you mean by 4S btw?

[MadInventor 3884]

1 minute ago, Apollo11 said:

So that would work then? And not put too much strain on the transmission and the like? I'm happy to stick with Nimh, at least for the time being.

At the risk of asking a bone question, what is this advanced timing? I've read it mentioned before, but don't understand what it is. I think I get what you're referring to re: one axle pushing/pulling the other: if the two motors aren't in sync, then one would be running faster than the other.

Clod transmission is pretty much unbreakable as long as you have steel pinion gears and roller bearings throughout. Advanced timing means the motor runs faster in one direction that the other. This is achieved by altering the angle of the brushes with respect to the magnets. What it means is that if you put advanced timing motors in a clod, one gearbox will run faster than the other, as one gearbox runs in the opposite direction to the other. This is why using cells with uprated voltages is popular over buying motors with advanced timing, as you have to find a motor with the timing advanced in the opposite direction to match it. These used to be commonly available for uprating Clods, but they are thin on the ground now. If you don't want to go LiPo you could always try a 9.6V Nimh, which will also work ok with that speedo

 

[MadInventor 3884]

2 minutes ago, Apollo11 said:

Just that ESC, or the motors as well? What do you mean by 4S btw?

Just the ESC. Still running it on 7.4V as my son drives it, but I have a 3 cell setup (11.1V) for my juggernaut 2, which has 2 silver cans and a 880 speedo.

 

4S is a 4 cell LiPo. 7.4V x 2, so a 14.8V battery.

 

[Apollo11 19]

19 minutes ago, MadInventor said:

Clod transmission is pretty much unbreakable as long as you have steel pinion gears and roller bearings throughout. Advanced timing means the motor runs faster in one direction that the other. This is achieved by altering the angle of the brushes with respect to the magnets. What it means is that if you put advanced timing motors in a clod, one gearbox will run faster than the other, as one gearbox runs in the opposite direction to the other. This is why using cells with uprated voltages is popular over buying motors with advanced timing, as you have to find a motor with the timing advanced in the opposite direction to match it. These used to be commonly available for uprating Clods, but they are thin on the ground now. If you don't want to go LiPo you could always try a 9.6V Nimh, which will also work ok with that speedo

 

Thank you. The pinions are the standard ones that came with the motor. I'll look out for replacing those if need be. The kit was built using sealed bearings throughout. I've done a search and read the instruction sheet that came with the Super Stock Motor and there's no mention of timing. So I think we're ok on that front.

[Apollo11 19]

Ok, I've purchased a Hobbywing Quicrun 880 ESC and looking at the user guide, it has these specs: see attached. What exactly is the motor limit telling me? I have a pair of Super Stock Motor type-BZ (23T) and a 5000mah NimH stick. Simple question, will this work?

Scan.pdf

[CoolHands 816]

Yes. Chuck it in

[whahooo 465]

The Hobbywing works with the Super Stock BZs. I Use it in my Wild Dagger even if i like the Tamiya ESC handlingwise better. It has a softer Brake, the Hobbywing brings almos a imidiate Stop wich often gets into a "frontflip".

[Juggular 4964]

On 5/14/2020 at 4:26 PM, Apollo11 said:

I have a pair of Super Stock Motor type-BZ

Super Stocks have advanced timing.  As @MadInventor mentioned, that's a bit of a problem

I tested 23t Sport Tuned at 1S (3.7v).  It was going 11,100 RPM going forward, 9,900 RPM going backward.  (12% difference) 

Super Stock is the same; the RPM is not equal both ways.  

Clod axles identical axles, but they are mounted opposite to each other.  For Clod to go forward or backward, each motor on either ends always has to turn opposite to each other.  That's fine for silver cans because they have neutral timing. (It will give you the same RPM forward and backward)  But if the motors are "timed" like Super Stocks, one axle will turn much faster than the other.  (you can test it. Mount both Super Stock motors. Then put a white masking tape to front and rear tire.  Run your Clod off the ground.  You'll see that front and rear won't turn in sync.  

In case of Wild Dagger family (another dual motor chassis with axles running opposite to each other), it is the rear axle that turns the "right way." The front axle turns the "wrong way."  Since the Clod axle was never used in 2WD configuration, I don't know which way is the right way.  If it's like Wild Dagger, the rear axle would want to go faster than the front.  That's a recipe for doing donuts (they pull the front brakes and let the rear rip).  

On sand, this would be less of a problem. But it still means less-than-stable 4WD.  (You might have seen showdowns for 1:1 AWDs. Subaru often does better than Honda, Toyota and Nissan. Because Subaru matches front and rear speed very well with their viscous center differential)  

Here is a photo of a clod chassis.  You can see how the motors are not facing the same direction.  

IF they were facing the same direction, it would look like below.  

So... both motors should have neutral timing. (or you can time one motor going forward 10 degrees, the other motor going backward 10 degrees)  

If I was in your shoes, I would re-time the Super Stock motors to zero.  Another member had done it for Clod.  Since Tamiya motors don't mark where zero is, it's bit tricky, but doable.  

 

 

I always felt Wild Dagger's handling wonky, I suspected that it's because of the RPM difference (even though I mounted silver cans--photo was taken when I was testing Sport Tuned).  I bought a tachometer to measure motor RPM.  If you want, you can measure exact RPM as you adjust timing.  

 

[Apollo11 19]

On 5/15/2020 at 9:25 PM, Juggular said:

Super Stocks have advanced timing.  As @MadInventor mentioned, that's a bit of a problem

 

Oh ****. Well, as they say 'Act in haste, repent in leisure'.

Thank you for the insight. I see those tachometers are around £12 on Ebay. Are they straightforward to use?

[Juggular 4964]

2 hours ago, Apollo11 said:

Are they straightforward to use?

Pretty much.  You know that bevel on the axle for the worm gear to latch onto?  That reflects the laser almost as well as a reflective tape.  But you can cut a sliver of reflective tape and place it on the bevel.  

You run the motor, and just shine the laser on the axle. Angle it about until you find a stable reading.  If you have a 18560 battery like the photo, it's easier to use that.  The motor doesn't jerk around as much.  What you are after is the difference, not the exact RPM at 7.4v. Lower voltage would not matter.  Less chance of shorting the battery, etc, etc. 

  

[Apollo11 19]

Thank you. I've got one now. It took a little while as I grabbed what I thought was a bargain on Ebay. But the seller had made a **** up on the listing and sent a pair of ladies hot pants instead. fortunately when I pointed this out, he swiftly provided a full refund. Getting to keep the hot pants would be a bonus if I had any use for them.

I was a little frustrated about the mem function. It just seems to scroll forwards. It's difficult to go back to a more recent reading. But never mind. I wrapped black electrical tape around the axle, leaving the bevel clear for the laser. Using the same AA battery, these are the readings I took on both motors:

                   Motor A          Motor B

Forward   7375                8375

Reverse    4933               4593

I was a little surprised at the difference in performance between the two. I got similar results each time I repeated it. One motor was consistently fast than the other. What I am planning on doing is adjusting the timing of motor A to get it as fast as possible in reverse. Then adjusting the timing of motor B to match it forwards. How closely do I have to actually get the two to match in order for it to work in the Clod?