Pairing a 6S rated ESC with a 8S rated motor?

[DankRCBoi]

Upgrading my Big Rock 6S. I got a 6S rated ESC (Max8 G2 160A) It has the same amperage as the last gen Max6. And a small 8S motor hobbywing 4990 1650kv. Will pairing it and running on 6S cause any problems?

 

[SirCrashALot]

Yes, the HW Max8 G2 spec list states a maximum motor size of 4278 and upto 2400kv.

 

[PrerunninF150]

As long as you keep it 6s I think you should be fine. It boils down to amps and the lower the Kv the lower the amps. A 160a esc should be enough if it is not overgeared or running paddle tires. Fair warning though if it blows up it not my fault

 

[SirCrashALot]

the lower the Kv the lower the amps.

Nope. That's not how that works. Same motor size, lower kv, ends up in same amp draw. Just read some more spec lists from whatever manufacturer, TP, Rocket and you will see.
The 49 size motors are amp hogs.
If that esc could handle them without problems, HW would offer a set.

 

[rotauq]

Nope. That's not how that works. Same motor size, lower kv, ends up in same amp draw. Just read some more spec lists from whatever manufacturer, TP, Rocket and you will see.
The 49 size motors are amp hogs.
If that esc could handle them without problems, HW would offer a set.

I disagree. Cansize for the motor determines the max power it can pull without burning out. Its based on how much heat it can disperse. The more surface (and a little bit of efficiency rating) will determine the watt rating.
Manufacturers sheets use that max power rating / rated voltage = max amp rating.
I practice the actual load will be lower. regard KV as electrical gearing aside from you mechanical gearing. Without any other changes to the car a lower kv motor will reduce the top speed and the ease to reach it (thus pulling less amps)

So back to OP.

Upgrading my Big Rock 6S. I got a 6S rated ESC (Max8 G2 160A) It has the same amperage as the last gen Max6. And a small 8S motor hobbywing 4990 1650kv. Will pairing it and running on 6S cause any problems?

Yes you can put an endlessly huge 8S motor on a smaller 6S rated esc (and car). The 8S motor and larger motors in general will have a lower kv, thus making less rpm's per volt. You would have to gear up to compensate the reduction of kv's (increasing the load) until you reach the cuttoff of the esc. Little added weight of the motor will increase the load a little, but you'll feel that mostly on driving characteristics.
But no, it will not really be an upgrade for your bigrock. The max8 might be slightly better than the stock esc, but will still limit the benefits of a bigger motor, it might feel a little torquer but that's it. You'll need a max6g2 to propperly unlock the motors potential.

 

[DankRCBoi]

I went out for a run anyway, it thermal shutdown a few times after full acceleration. I'll let you guys know if it catch on fire.

 

[Chapinb]

If can size us the same, the lower kv will pull less amps.
Bigger can, lower kv gets a little muddied. Geared to the same load, amp draw will remain similar, within reason in most cases.

That combo will be fine. Max gearing will be determined by the esc temp though. Keep an eye on the esc temp as the motor will run cool with any reasonable gearing.

 

[rotauq]

Gearing down will help keeping it cool.

The max8g2 might be rated for 160A, but it's thermal capacity (heatsink size + fan) is not that great.

 

[King blitz]

@DankRCBoi welcome

 

[Garcbomber]

G2S would be much more manageable with gearing/punch/timing monitoring on the fly.

I can overgear the max4/xlx2 with a small 4278/higher kV motor and get it to cogg-thermal out the low end/amp draw flipping the throttle during an entire high grip bash.

I’m sure your rolling resistance is far from ideal, but those are the variables an entry level troubleshooter will get to last before pointing at the electronics. Probably also trying to cram 10kmah Lipos in with the ESC/Motor combo that are obviously not designed to pair, especially at factory punch/current unloading parameters.

 

[parcou]

Welcome and good feedback!