Cooling

[revkev91]

Hey guys, I'm running my yeti on 3s 5000msh lipo. i have noticed that the motor gets a bit. Just wondering what people have done for cooling.

[OhioSuperSport]

Get a castle sv3 fan for the esc and a castle blower fan for the motor.

[cmbscx10]

I don't here very good things about the Castle blower fan. I am a fan of the Hobbywing C1. Run one in my Slash and will get one for the Yeti but need to drop a tooth or 2 on the pinion first.

[revkev91]

Thanks guys

Just wondering if you drop a tooth on the gear will it lose topend speed? And what gear ratio would you drop it to.

[Zombi]

Best solution is to ditch the stock electronics as they just thermal all the time if you try and do any crawling. I tried lowering the pinion to a 12T, updating the ESC software, underdrive gears in the rear diff - none of which stopped it from getting too hot.

I now have a Tekin RX8 G2 and Pro4 HD and no more thermals. WIN.

And of course you'll loose top-end if you drop pinion size...!

[cmbscx10]

What Zombi said is true for the ESC/Motor from what i have been reading. If you can justify or have $350 laying around for the Tekin RX8 G2 and Pro4 HD then by all means do that. I personally would go to an entirely different vehicle id i had to do that.

If you don't and can loose a barely noticeable amount of speed, $10 for the fan and a few dollars for pinions in either 14 or 15 tooth should be fine. I never thermal with the stock gearing but i also don't spend all my time rock crawling. The yeti is not designed to do that and knowing that will help you decide what to do. A thermal temp gun and a stop watch are great tuning tools. If you thermal at 20min. Only drive for as long as you don't. I can buy almost 4 sets of the stock ESC/Motor take offs for the price of one set of the Tekin. Great combo but i'll change my terrain, vehicle and driving habits before i dropped that kind of $$.

[Zombi]

Aye for bashing the stock elecs are fine and i never thermaled it whilst just racing about. So if you don't intend to do any crawling leave it as is and go for some cheap cooling options.

Tell you one thing though, the Tekin gear made an awesome difference, both at top and bottom end. Bottom particularly, as at low speed there is just no cogging any more. Before i changed the motor and ESC, I couldn't keep up with the wraith boys on our trail days. Now the Yeti can do things they cant (crawling-wise), mainly on the crazy steep inclines. It becomes a completely different truck.

[Poprivet]

I recommend taking the middle path.
To handle both crawling and high speed. a sensored system is a must. But you don't have to go all out $$. There are many options out there. Almost any would out perform stock electronics. Mamba max pro is half the price of the rx8, and an awesome all around speed control. Paired with any sensored 4 pole motor around 4000kv would do the trick. I have read good things about the holmes hobbies sensored motors, also half the price of tekin. I'll be trying one in my next rig.

[OhioSuperSport]

Adding an under drive to just the rear won't help anything. Dropping a tooth and adding a fan to the esc will solve your issues. The esc is basically an sv3 and the yeti being 4wd and on the edge of its weight limit will make it work hard.

[Zombi]

I doubt it'll *solve* the issues at all, but it will help. And cooling just the motor is only half the problem, the ESC also generates tremendous heat.

As suggested above by Poprivet, the MMP is an excellent middle-ground. As for motor KV, that is dependant on what battery you run. for a 3S you're better off with something around 3000KV. If you run 4000KV on 3S all you're going to do is generate even more heat and deplete your batteries faster.

This may be of interest if you decide to go for a Tekin motor:

http://www.teamtekin.com/pro4-hd.html

Input Voltage:
2S - 4300kV / 3500kV
3S - 3000kV / 2500kV / 1850kV
4S - 1850kV

[Justin82]

When my kit gets here I plan on gearing a bit wider, 14 pinion to be safe