I got tired of reading the mixed reports of whether or not the stock ESC (VXL-3s) could run the Novak HV Pro motors, so I ordered one and tried it myself. Guess what.... it works!
I also think I've found the cause for some of the unsuccessful reports: the sensor cable port on the VXL-3s makes it very tricky to get the connector fully seated. The first time I tried it, I got low-speed cogging, it ran smoothly at mid-range speeds, then it stuttered horribly at full throttle. I figured it must be a problem with the sensor cable. A little bit of patience and some help from a small alllen wrench (or any small solid item that can be used to apply pressure to the sensor cable connector), and the connector snapped into place. Now I have VERY smooth low speed throttle control and full throttle works just fine as well. I tried this with a ******* 5000 mAh 20C 2s lipo, btw.
Here's what it looks like installed:
Here's proof that it runs at low speeds without cogging: http://www.youtube.com/watch?v=7-YtdMFRcDs&fmt=18
I'll get some higher speed video sometime when it's not the middle of the night.
Here's the details, in case anyone else wants to repeat my success. Acquire the following:
- The Novak HV Pro motor of your choice. I picked the 5.5t.
- A 32p pinion gear of your choice that fits 5mm motor shafts. I'm starting with a 15t pinion.
- TRA3342: Traxxas Bullet Connectors (Male) (3) (VXL).
- TRA3628: Traxxas Sealed Receiver Box Kit (for relocating the receiver).
- 90+ cm of 12 gauge wire.
- A PVC electrical box cover (looks like a lightswitch cover without the hole for the switch; used to make an ESC mounting plate).
Remove the motor, ESC and receiver + receiver box from your Slash 4x4, then use a Dremel (cutoff wheel and sanding bits) to trim down the electrical box cover to the following size/shape:
Mark and drill holes for the screws (line up with existing mounting holes on the chassis), then use a large drill bit to add a countersink to the screw holes. Use the 2 mounting screws from the stock receiver box to mount your custom ESC mounting plate. The heads of the screws should be flush with the surface of the plate, thanks to the countersunk holes.
Install the new receiver box in front of the steering servo (refer to first picture in this post). The wires coming out of the servo make it a tight fit, but the receiver box will mount to existing holes on the chassis there. All necessary hardware and even a tube of grease is included with the receiver box. Just set the receiver in the box for now without taping it down.
Get the motor mounting plate swapped over onto your new Novak motor and set it in place for some test fitting. Figure out exactly where to mount the ESC on the custom ESC plate (refer to first picture in this post) such that the throttle servo cable can reach into the receiver box and plug into the receiver, and leave some clearance for the sensor cable coming out of the end of the motor. When your happy with the location, stick it down with some double-sided servo tape. At this point you can finish installing the receiver into the new receiver box, and get the servo wires and antenna all routed, plugged in, etc. Follow the instructions for the receiver box to get everything closed up and sealed properly. All that remains is the motor itself.
For the motor wires, I cut my 3 wires to be 27cm long each. Follow the included instructions for soldering the male bullet connectors to the wires. Don't put the heat shrink on the connectors yet. Follow the instructions for the Novak motor to solder the other ends of the wires to the motor's solder tabs.
As warned by the motor's instructions, DO NOT hook up the motor and try running it without it fully mounted. You shouldn't run the motor without any load. Mount your pinion to the motor, fully install the motor and set your mesh. To wire the motor to the ESC, pay attention to the labels on the end of the motor next to the solder tabs. They are labeled "A", "B" and "C". The 3 wires on the ESC are similarly labeled (look on the ESC next to the wires). Match these up and plug them together. We didn't install the heat shrink tube on the motor wire connectors yet so that we can verify the wiring first. It's still not time to do the heat shrink tube...
Plug the motor's sensor cable into the Aux port on the front of the ESC. It WILL fit in with the rubber seal still in place (just remove the plastic cover from the hole). Use a small allen wrench or similar to help push the connector into the ESC Aux port. Be careful: the connector has small tabs on it that prevent it from being inserted upside down. Don't force it too hard if you aren't sure that it is lined up correctly. When it is fully inserted, you should be able to tug on the cable lightly without the connector moving or coming out of the Aux port.
Hook up a battery and make sure the motor is working.
If nothing happens at all, then double check that the ESC is hooked up the the receiver properly (ESC is channel 2, steering is channel 1; there's also 2 slots for channel 1 on the receiver), double check your soldered connections, and double check that you matched the A's, B's and C's when you plugged the motor into the ESC.
If the motor runs, but you get cogging at low speeds and cogging/stuttering at full throttle, then your sensor cable is not connected properly. You should be able to make the car move smoothly at very low speeds as shown in my video.
When you are satisfied that everything is working properly, unplug the the motor wires one at a time, slip the correctly colored heat shrink tube onto the wire, then plug it back together. With all the wires plugged together, you can line up the heat shrink tube perfectly against the heat shrink on the ESC wires, then apply heat with a heat gun or similar to shrink it into place.
Finish putting various things back on your truck, then go have fun!