brushless conversion help!

[CerberusVI]

So I've converted my associated monster gt to brushless recently and have run about 3 packs through it and I'm having some problems. So first off here are my specs

Monster gt locked in 2nd gear
Castle mmm esc
6s 40c 5000mah lipo
Hk kb45-10xl
20/54 gearing
Maxx mashers wheels (5.8"?)
I'm geared for about 30

I've peaked this motor a couple times at 200 while trying to play w/ the gearing, took it apart after the 1st run and found a broken peice of windig. Being new to brushless I cleaned it up and reassembled it. Now I took it apart 2 packs later and found more carnage! More broken windings. Tried a bunch of different gearing and tire sizes trying to bring my temps down but it seems every 10mins the motor hits 200f. So I'm wondering if I should try a lower kv motor? I've drilled the front and rear of the kb45 but I believe its too late now and I need a new motor

[CerberusVI]

Ran the motor tonight, feels a little down on power. after 7 mins the motor hit 200f again. due to the size of the motor i cant gear down anymore than i am now. I might be able to go to a 18 or 19 but i don't think it will drop the temps enough to make them reasonable to run.

So now i need help with planning a new setup, I was thinking of a castle 1515 2200kv motor. using the setup calculator if i geared for 40mph on 6s the motor would be around 49k Rpm which seems really high. I'm pretty set on 6s as i have already purchased the battery

[ransom]

those older style 2 pole motors are not torquey enough and run hot and die fast
newer four pole in the right kv range will be much better 1900-2300kva

castle or red leopard seem to be reliable and good value

MG is a big truck with big wheels can you fit a larger spur for lower gear options?

[CerberusVI]

It seems to have plenty of torque at 30mph 3/4 throttle i can still punch it and do wheelies. I went from a 52 to a 54t spur. I had to switch to the Robinson racing steel spur because i couldn't stop melting plastic spurs even with the slipper all the way tight

[x-y]

hk motors = shits ....... if you search a good motor for your car buy a 4074/4274 or 4082/4282 4 pole motor ........ you will see the difference ;)

[ransom]

yep the two poles hk kb kd and fieago style motors just run way too hot
i have three dead ones here 3674mm size
even running them with a fan mounted in heavy ext savage
same truck with 4060mm red leopard 1900kva runs cool and strong with no fan

motor tech is just getting better and cheaper and more efficient

[CerberusVI]

@ransom
How heavy is your savage?

So if I wanted to go cheap just to test the waters say with a tacon 4074 2000kv motor I would be ok? I want to gear anywhere from 30-35 for bashing but I'm wondering if motor rpm is going to be really high at that gearing. Or should I shell out the extra money for a leopard lower kv motor?
Here's a link to the motor im considering
http://www.hobbypartz.com/96m801-4074-2000kv.html

[brian015]

I have one of those tacon 4074's but haven't tried it yet. I've been very happy with my leopard 4065, though, so I expect good things from the tacon.

For your setup on 6s, though, the tacon's kv looks to be too high. Did you put it in the top speed estimator and see what pinion you'd need?

[CerberusVI]

Using the calculator I would need a 14t for 34.95 mph and it says motor rpm would be 44k. Granted 35 is plenty fast for bashing in my needs so 14t is the biggest I would probably go.

Diff ratio 3.308
Trans ration 1.701
54t spur
5.8" tires
6s 22.2v

[suicideneil]

I wouldn't be affraid of trying a lower kv option for 6s lipo use, something like 1600-1800kv would work quite nicely.

The castle 1717 would be great for that size of truck, it is 50mm in diameter but would be worth a try as it is currently only $70 ( special clearance price ):

http://www.castlecreations.com/produ...le_motors.html

[CerberusVI]

I wouldn't mind trying the 1717. Its kinda what I had in mind, but the problems is with where my motor mounts and the transmission. The 45mm motor I have now sits butted up against it and smallest pinion I can fit now is a 18. I've also heard of some issues with running the 1717 on 6s?

[ransom]

i have two savages one is 4.5 kg 10.? pounds
one is 5kg 11 pound
without batteries is that heavy or light
here is the speedcalc for the heavier one i only run 4s

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.5366847826086956
Other Ratio: 1
Spur Tooth Count: 49
Pinion Tooth Count: 13
Total Voltage: 16.00
Motor KV: 1900
Tire Diameter (inches): 5.84
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 3.77 : 1
Total Ratio: 19.15855 : 1
Tire Circumference (inches): 18.35 inches (466.01 mm)
Rollout: 0.96:1
Total Motor Speed: 30400 RPM
Vehicle Speed: 27.57 mph (44.28 km/h)
Effective KV Value: 1900
KT constant: 0.71 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

savage 2nd cog

[brian015]

Originally Posted by CerberusVI

Using the calculator I would need a 14t for 34.95 mph and it says motor rpm would be 44k. Granted 35 is plenty fast for bashing in my needs so 14t is the biggest I would probably go.

Diff ratio 3.308
Trans ration 1.701
54t spur
5.8" tires
6s 22.2v

Then I'd give the tacon a try - if you're looking for a cheap option, I think it fits your needs. (I also agree that the 1717 would be better if you could make it fit.)

[CerberusVI]

Well i went ahead and ordered the Castle 1717 motor this morning. I'm hopeful i can make it fit and gear it right, but if not i have other plans! Before i started this project i wanted to build a center diff mount, now if my transmission idea doesn't work i will be going that route!