SirJangly

iTrader: (14)

Hey guys! I am getting a mamba max with a 6900kv motor in tomorrow. Will I have any problems running with a stock setup? Thanks in advance!

hound_dogs_01

iTrader: (16)

youll cook that motor for sure... WAY too high of a KV motor... you need like a 3500kv motor for a slash....

Alex

SirJangly

iTrader: (14)

Would it be okay just to run for a few minutes? What do you mean by cook? Why would they sell motors like this if they were prone to "cooking?"

fr0z3nfr0g

iTrader: (1)

you would have to gear it way down. the 6900kv motor, by my knowledge, is ment for crazy speed. if you put it in with stock pinion and spur gear, it would be working too hard to accelerate the car, and would overheat really fast. you would want a big spur gear and a small pinion to keep the motor doing what it does best, spin really fast. with the lower kv motor, you get more torque and less rpm, so you could still gear it to go fast, but it would not overheat as fast. correct me if im wrong

SirJangly

iTrader: (14)

QUOTE=fr0z3nfr0g;6078421]you would have to gear it way down. the 6900kv motor, by my knowledge, is ment for crazy speed. if you put it in with stock pinion and spur gear, it would be working too hard to accelerate the car, and would overheat really fast. you would want a big spur gear and a small pinion to keep the motor doing what it does best, spin really fast. with the lower kv motor, you get more torque and less rpm, so you could still gear it to go fast, but it would not overheat as fast. correct me if im wrong[/QUOTE]


Oh gosh. That is no good

hound_dogs_01

iTrader: (16)

thanks for explaining it to him

Alex

sLaSh It UPP

iTrader: (1)

yeah a mamba max 6900kv is WAY TO HIGH you should get a vxl motor or a 4600kv or a 5700kv sidewinder or mm

bowl806

+1 !

JAM MaxAmps

The motor won't cook If you stick with say 7 cell nimh or 2S Li-Po max and gear correctly. Just follow Castles gearing chart and run the largest spur gear possible and a pinion gear in the 15T-20T range. Keep motor temps under 190 and you should be good. I ran a 7700 in my old B4 buggy for a couple of years following the same general rules and never had any issues. But get ready cause your Slash is gonna move out pretty good. 45 MPH plus if you can keep it under control. If your looking for more of a bashing motor the 5700 or the 4600 are better choices.

Jason

sLaSh It UPP

iTrader: (1)

+1

Duster_360

iTrader: (21)

Go with the 4600 motor if you're even thinking about running 3S in that setup.

SirJangly

iTrader: (14)

I will only run 2s I am not crazy Isn't the stock spur really high? I believe the pinion is 18? Should I use the 16?

JAM MaxAmps

Stock spur is 86 you'll have to looks at the on-line parts break down at Traxxas.com but there are a couple larger options for the spur I think.

Jason

SirJangly

iTrader: (14)

Okay, that was crazy. half throttle, going uphill on our court, it was screaming. Any more and it would have flipped over! I put the motor in the for sale section

Also, the esc heatsink and motor were really hot after only two minutes. This was to be expected though, right?

Duster_360

iTrader: (21)

My MM/5700 Slash takes a 4-5 min to come up to temp ~180F and it pretty much stays there.

I'd expect 6900 to get hotter sooner about like you experienced.