Help me with gearing!

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SarsK9

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Arrma RC's
  1. Granite
  2. Typhon 6s
Wasn’t sure where to post so just putting it in general chaos. I’m building up my Kyosho Fazer as I plan my typhon build. I’m not as knowledgeable so need from help from some veteran rc guys. I’m gonna be running a castle sw4 5700kv on 3s. I know, I bit much for sub 4lb car but I want a crazy parking lot Basher. As of now I’m stuck with a 68 tooth spur (I haven’t found any others that work yet) and have a 32 and 37 pinion but I’m sure those are way to high. I know I’ll need to run and check temps to know for sure but I just need a general starting point.
 
I use bolo speed calculator; located in the video description. It as an ms excel sheet with built formula.

 
The Castle 5700kv motor is recommended as a 2S motor though. You will probably see high temps with whatever gearing you use. I’d probably use the 4600kv or possibly even lower kv motor if using a 3 cell pack.
I use the 4600 in a 2wd rustler and it cooks on 3S
 
On their page they put 2-3 for 1/10 on road cars under 4lbs for the 5700.
 
I wouldn't use 3s on that motor regardless of the gearing or vehicle weight.
You could probably do 3s for single speed pass and then wait 5 mins to cool down.

I was able to do 70+mph with a similar KV on 2s in a 4Tec 2.0
 
I wouldn't use 3s on that motor regardless of the gearing or vehicle weight.
You could probably do 3s for single speed pass and then wait 5 mins to cool down.

I was able to do 70+mph with a similar KV on 2s in a 4Tec 2.0
I’m still learning, have a lot left to learn but that’s what I’m looking for. Want excessive power and want to run 70%-wot for a whole pack without hitting thermal. Would you suggest the 4600 on 3s or the 5700 on 2s?
 
For how light that car is I think 5700kv on 2s is going to be best. (consider the 3s pack weighs a good bit more)
If you are set on 3s then Id go further down to something like 3500kv

With the 5700kv and assuming I found the correct differential tooth count online and tire diameter that should put you right around "real world" 50mph.
That car will be hard to control even at those speed I imagine.

fazer.JPG


It would still be a good idea to get a heatsink for the motor, then monitor temps. They sell cheap IR guns on Amazon.

-Liberty
 
Thanks, I think that’s about where I’d want it at. Everything looks right on there but can’t check till I get home. I’ll be getting a yeah racing heat sink fan combo. I really didn’t think about the extra weight of 3s vs 2s, and in a car that small I’m sure thatd affect it quite a bit. Thanks for your help
 
I definitely will. Slowly accumulating all the parts but I’m going to start a build thread once I’ve got everything in hand
 
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