Motor selection for Slayer
 

I have a 2.5 Revo sitting on the shelf that I haven't fired up for a couple years. Ever since I went BL with my other models, I haven't had any urge to go back to Nitro.

Now that the Slayer is coming out, I'm very interested in converting my unused Revo to a Slayer and to BL power. I'm sure motor selection would be identical to the Revo.

ESC would be one of my MM's or maybe a new MMM. Battery power would be 4s-6s.

Options:
Neu - probably more than I want to spend.

Feigao - NICE prices. 8xl? 9xl?

Medusa - which one? Vendor? Price?

AXI - haven't heard much about them. What do they offer in the 2000 rpm/v range?

Other?????

Neu- $$$ yeah, but quality with it.

Feigao - cheap for a reason.

Medusa - wait for the 70mm version, or the existing 60mm V2 models are very good, just choose Kv rating according to voltage used. Best to order direct from them, or via mike really.

AXi- only if you want to build an outrunner powered truck with direct-drive, nothing higher than about 1000kv available (plane and heli motors, they are).

CastleNeu is due out end of the month or so- Neu type quality for only ~$100 or so....

Lehner - german, brilliant, $$$.

Hacker - same.

Hobbycity - god no, spinning toasters of death.

Megamotors - 22/35 or 22/45 models, choose kv according to voltage again.

I think due to the reduced weight of the slayer, the medusa would be a great option. Mine ran well, just not quite enough for my maxx.

:lol: :lol: :lol: He's right, though. I've been eyeing the new Medusa V2's myself. Medusa or Neu would be my choices. Or, if you're in Europe, definitely consider Lehner as well.

I'll be converting a Slayer myself when they come out and trying the Medusa 36-60 1600kv on 6s .

I have the 1600kv in my X2 truggy on 5s and a spare one for my buggy or Slayer , which ever i get going first.

If it's not up to the task i'll just get the 70 size when Medusa releases them , for the money they can't be beat .

Sounds like the 70 might be just the ticket. Guess I'll wait around a bit and maybe buy a quart of nitro. . . ewwwww. :(

The 50mm Medusa will be plenty if you keep the 2-speed and mechanical brakes. I ran a 50mm 2200 in my Revo and in my Losi 8ight buggy and it worked great. If you wanna go Neu I'd say the 1509 would be the ticket.

Wow the 50 was alright with that set up , i'm quite shocked but thats good news .
What batteries and esc did you use in that set up .

I ran the Tekno RC conversion, 4s 16c Hyperion 5350mah battery, MM with Castle BEC. The Medusa's are good motors, the only negative i have to say about them is I have had the endbell pop off on me. Not that big of a deal, the older version of the Neus were subject to that too. I just put it back on and ran a bead of CA around it, no more problems.

What do you all think of the gearing change in doing a Revo 2.5 -> Slayer conversion? To do it right would require new tranny case and gears as Traxxas changed the gear ratio to accomodate the shorter tires.

Would it be possible to stay with the Revo tranny and gear the spur/pinion accordingly?

You can play with it in the speed calculator to check for sure, but I think you may be able to use stock gearing and just go smaller spur/larger pinion to make up for it. The brushless motors have a little more capability than nitro.

Edit:

Here it is set up with a 1512 1.5d running 4s lipo and the Revo wide ration second gear. You could also sub the 50mm 3300 kv medusa in there as well.

<table border="1" cellpadding="2" cellspacing="0"><tbody><tr valign="top"><td nowrap="nowrap">Differential Ratio: </td><td>2.8461538461538463</td></tr><tr valign="top"><td nowrap="nowrap">Transmission Ratio: </td><td>2.111111111111111</td></tr><tr valign="top"><td nowrap="nowrap">Other Ratio: </td><td>1</td></tr><tr valign="top"><td nowrap="nowrap">Spur Tooth Count: </td><td>38</td></tr><tr valign="top"><td nowrap="nowrap">Pinion Tooth Count: </td><td>16</td></tr><tr valign="top"><td nowrap="nowrap">Total Voltage: </td><td>14.8</td></tr><tr valign="top"><td nowrap="nowrap">Motor KV: </td><td>3300</td></tr><tr valign="top"><td nowrap="nowrap">Tire Diameter (inches): </td><td>4.37</td></tr><tr valign="top"><td nowrap="nowrap">Tire Ballooning (inches): </td><td>.5</td></tr><tr valign="top"><td nowrap="nowrap">Motor Current Draw: </td><td>0</td></tr><tr valign="top"><td nowrap="nowrap">Motor coil Ω: </td><td>0</td></tr><tr valign="top"><td nowrap="nowrap">Spur/Pinion Ratio: </td><td>2.38 : 1</td></tr><tr valign="top"><td nowrap="nowrap">Total Ratio: </td><td>14.2703 : 1</td></tr><tr valign="top"><td nowrap="nowrap">Tire Circumference (inches): </td><td>16.87 inches (428.51 mm)</td></tr><tr valign="top"><td nowrap="nowrap">Total Motor Speed: </td><td>48840 RPM</td></tr><tr valign="top"><td nowrap="nowrap">Vehicle Speed: </td><td>54.68 mph (87.83 km/h)</td></tr><tr valign="top"><td nowrap="nowrap">Estimated Adjusted Speed: </td><td>51 mph (81 km/h) - 7% loss</td></tr><tr valign="top"><td nowrap="nowrap">Effective KV Value: </td><td>3300</td></tr><tr valign="top"><td nowrap="nowrap">KT constant: </td><td>0.41 oz-in/A</td></tr><tr valign="top"><td nowrap="nowrap">Motor Torque: </td><td>Amperage not specified...</td></tr><tr valign="top"><td nowrap="nowrap">Final Torque: </td><td>Amperage not specified...</td></tr><tr valign="top"><td nowrap="nowrap">Final Power: </td><td>Amperage not specified...</td></tr></tbody></table>

What did you use for tire size? Won't the Slayer have the same size tire as the Slash? Slash is 4.37" diameter for a 13.7287 circ.

Also, refresh my memory, what are the stock Revo tooth count on the diff gears?

stock Revo diff gearing=37/13

I used the slash tire size but added 1/2" to the radius for ballooning.