A question about my slash setup...
 

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!

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

Alex

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?" :(

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=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 :(

thanks for explaining it to him

Alex

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

+1 !

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

+1

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

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

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

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?

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.

Yeah, I am about to get some bullet connectors so I can hook my velineon motor to it. :). The banana plugs on it are 4mm, right?

I think the Castle are 3.5mm and Trx are 4mm. Post info if you can either confirm or deny-Thanks

I just got back, its 4mm :)

thanks for the reply! I might need that info if I change my VXL w/Mamba ESC. Change MM to 4mm for sure?
Thanks!

I put the velineon motor in. Runs much better. The esc did not get hot, but the motor did...should I lower the pinion to 14?

see now you have a great set up

Yeah, I believe I should lower the pinion though, as the motor is still getting hot. Could this be because I was using a nimh, as opposed to lipo? Should I get a 14 or 16 pinion? Stock is 18 I believe.

I'd make small changes so you don't suddenly wind up undergeared after a big change. 16t would be the one I'd try and if its not enough, then the 14t.

NiMh vs lipo - no, its not the cause of the temp issue. If them NiMh wasn't up to the task, the batt would have gotten hot to really hot.

im runnen a mamba max and vxl motor on my slash , gearing is 21/86 and perfect , no heat issues at all with 6cell , 7cell and 2s lipo ... for the 6900kv motor i wouldnt go above a 16t pinion with the stock spur and watch your temp's and gear from there. you really dont want any motor going above 180 deg's i believe or it will start to de-magnitize. As for the esc(mamba) i believe it will automaticly shut down if it gets to hot but dont qoute me on that as i have never had it happen. Id say for a slash stick with the vxl motor or sell your 6900kv motor and get the castle 4600kv. They still will both be very fast with the right gearing and batteries. expect anywhere from 35 mph - 60+mph with the right batteries and gearing. GoodLuck