1/8 buggys with outrunner power
 

Hi, I'm thinking of converting a Kyosho MP-6 to brushless using a outrunner to replace the center diff.( I know it's easier using an inrunner mounted next to the center diff, but this intrigues me) How big an outrunner do I need? I saw pics of someone else's conversion and they were using a HXT 50-55-450. Do I really need one that big or could I use a Rimfire 42-50-1000? Thanks, Don

Its an art, trying to figure out which outrunner to use for this kinda thing in any given setup- Sike is the guy to talk to...

Does Sike visit this forum? Don

The outrunner you choose will depend entirely on the speed you wish to achieve, and the voltage you want to use. Keep in mind that 4s Lipo shouldn't be used for anything higher than about 45mph.

That's right where I want to be. I'll be using a 4s a123 pack(13.2 volts). An outrunner with a KV of 1000 would produce 13200 rpm which should give a speed of 40-45 mph. I was also concerned about torque- would the motor I selected (Rimfire 42-50-1000) have enough? Don

1000kv is alot in a DD setup, you will need a huge outrunner to give you the torque you need. 4s A123 probably wouldnt be enough to get you to 45mph with any runtime, you using 1or 2p?

I would go up to 5s a123 and a lower kv motor. Startup load is high with a direct to diff outrunner, and the more voltage you have the better it will run. I guess you plan to run a MM? Or maybe the MMM?

Your rimfire motor should be ok, but I would go with the 42-60-800. What are your diff ratios and tire size?

At the moment the battery is 1p. I've got a MM but would like to have a MMM. Diff ratio is 3.3 and tire size is 4.375 dia. Don

The mm is fine up to 5s a123, just use and external bec and disable the internal bec in the MM. 1p should be ok, to keep the weight down, but you will get 15min runtimes or so.

Forgive me, my earlier advise on the 42-60-800 was not good.

I would say that you should run 5s a123, a 600-650kv outrunner, and the MM. Speed will be in the low 40mpg range, which should work fine. The rimfire 42-60-600 would be ok to use, maybe go up to a 4120/14, 660 kv, outrunner, as those are very nice motors, and they will work well in your application.

http://www3.towerhobbies.com/cgi-bin...?&I=LXPPX8&P=7

OK I'll take a look at the 42-60-600. Thanks, Don

I've got my motor. I've centered the motor shaft (thanks Takedown) and have temporarily mounted the drive cups to it. I find myself in need of 2-6mmto5mm bore reducers and a motor mount to mount it to my MP-6. Is this something Mike could come up with? Thanks, Don

OK, should I e-mail Mike directly? Don

bump

Yeah, Mike should be able to make the bore reducers.

How about the motor mount? Don