Ok, I see what you're talking about now. It sounds like those old car horns... AaaOOOOgaa :smile:

How are the bearings in the motor? Any side play at all could be causing that noise. Is there any linear play in the rotor, like there might be a spacer missing? Have you ever tried spinning a plastic lawnmower wheel really fast and it kinda flips out and vibrates? Same idea there.....mechanical resonance.

It could also be interference in the motor wires. You might want to try either braiding them or shortening them a couple inches and see if it helps.

Check your Rear diff... Sounds like the pinion is slipping on the ring gear to me....

Listening again, I'd also check that the output shaft of the motor isnt slipping on the Grub Screw of the Center driveshaft.

You said it does it when you hammer it?

I can hear it. I've heard it before. :yes:

It's the ESC losing Sync with the motor.

Try turning the punch control off, and turn the timing down one notch.

It's probably a result of the punch control, but another suggestion would be:

Upload a different version of the software to your controller. Some versions are better than others at handling outrunner motors.

What version are you running now?

Nice truck! She runs pretty good, it just needs a few adjustments.

yes it happens when i punch it from a rolling start,
no it isnt the diff slipping (i know that sound off by heart :lol:)

i'm running the latest and greatest beta firmware. should i drop back to the last non-beta edition?
and i'll ditch the punch control and see if that helps (although with no slipper i'd like to be able to use it lol)

issues solved!
shortened and braided motor wires, lowered punch to 20%, set timing to 15, went back to firmware 2.42 (i think...the least non-beta one anyway) and it's all good..think the wire shortening did the most difference though.
it's brilliant now, even on a crappy half flat 4s i got zero cogging :yipi:

Nice! :great:

Excellant!

Outrunners have a different feel than alot of setups, but definately make some good power.

Now it's time to drive it like ya stole it. LOL