Outrunner question

[sikeston34m]

Originally Posted by lincpimp

Heres one for you Sike, or anyone else with some experience with Axi outrunners. I have a hb lightning street, which is basically a stretched cassis 1/8 buggy with street tires. I am planning on doing a direct to diff conversion, but with a twist. I would like to run two outrunners, one for enach diff. I would connect them to the diff with short dogbones, or something similar. I would like to run 2 4120/14 motors and a pair of the OEM Setilon HV escs. I plan to run somewhere between 6s and 10s lipo.

Now, I am wondering if the motors would be up to the task. On 10s they would be spinning around 24k rpm. Is that too much for an outrunner? These are supposed to have 3 bearings, so I am guessing that they will hold a load better than a two bearing model.

This will be a strictly on road car. And I will mainly be doing high speed runs with it. So what do you guys think?

I want to do a Hotbodies Lightning Stadium Pro Conversion! *drool* LOL

The 4120/14 works great with 4S to 6S. If you're hard set on the 4120 and plan to do HV, go with the 4120/18 or the 4120/20.

The 4120/14 would probably work on with higher voltage, all the way to the point where heat becomes an issue, BUT anything really high speed becomes hard to control.

Here's my suggestion, Do some math.
You need:

1. Tire Size
2. Diff gear ratio
3. Decide on your "target" operating voltage.
4. Decide on your desired top speed.

My Revo conversion with the 4120/14 tops out around 45mph. But remember, with outrunners, the lower the kv, the More torque it will have.

I'm spinning the Diff pinion gear at 10,000 rpms on 4S Lipo with a 5.75" tire.

If I were running HV, I could spin the Pinion gear at 10,000rpm with 294KV motor at 36 volts! Same top speed, but MUCH more torque. Much more acceleration!

Consider this. The AXI 4130/20 is 305kv. How much more power would it make, than the 4120 on 36 volts? The 4130/16 is 385kv. Pick your top speed and go figure.

The 4120's are good. There are some other kv options in the 4120 line also.

Ummmm, remember to get the cooling fan.