theunleet

So I know nothing about Brushless motors basically. I know lower KV gives you more torque..... but I am not interested in that. I want to buy a HIGH-KV motor and try it out in my VXL-Rustler for speed runs. I have the Anaconda REAR tires, stock FRONT tires.

So I believe the highest KV Motor I have found.... which will not work with my VXL ESC because it is sensored is 10650KV(but the Orion goes down to 2.5T so maybe thats higher?)

Hyperion RC Car Swift SENSORED Brushless Motor $79.95 Bishop Power Products http://www.b-p-p.com (I bought a mamba max combo from them for $155)

[*]4900 KV[*]5850 KV[*]7150 KV[*]7990 KV[*]9130 KV[*]10650 KV[/list]Orion Vortex ProRace Brushless Motor $84.95 http://www.stormerhobbies.com
[*]2.5T[*]3.0T[*]3.5T[*]4.0T[*]4.5T[*]5.5T[*]6.5T[*]8.5T[*]9.5T[/list]Castle Creations Mamba Max $77.95 StormerHobbies
[*]4600 KV[*]5700 KV[*]6900 KV[*]7700 KV[/list]Hacker Brushless E40 $74.95 StormerHobbies
[*]3.5T = 9320 KV[*]4.5T = 7200 KV[*]5.5T = 5800KV[/list]So is it even plausible to go with a 2.0T or 2.5T motor?(9000 - 10000+KV) I understand it will get hot, I just want to see what it will do and how fast it would run on my Turnigy 5000mAh 2S1P. Those are just some motors I found while at work(They have crappy filters so I can't surf most websites). Any other suggestions for good motors?

Slo-V Flyer

The reason why you dont want to use high Kv motors wtih just 7 volts for speed runs is in the long run they DO heat up, most do too much, too often, literally within 5 minutes. They may be fun, but you'll just heat things up in pursuit of speed that way.

You want a low Kv motor with HIGH voltage, to make up for the low rpm rating per volt. This is done with the motor geared low so the extra voltage will give it speed, and usually the best way to run COOLER and more efficient, generally without as much amp draw and the resulting heat that plagues uber high Kv motors.

Try to run a 8-10,000 Kv motor in anything but a 2-3 lbs on-road sedan geared for anything but useful practical speed AND not overheat. I think you'll find it next to impossible. Unless you literally just want to drive the car for 2 minutes up and down the street at 60-70 mph before causing overheating in many different components, with not real control other than straight line driving.

With a low Kv motor such as the VXL 3500 kv motor, and 3s lipo you have the ability to start off with slower speeds at first, and work yuor way up the gearing and voltage from 2s to 3s until you heat things up too much and find your peak performance.

theunleet

I think my rustler is a bit slow on the 3500KV motor it comes with... but then again I am running 2S1P. My 4600kV 2WD Slash seems to go faster than my VXL Rustler.... unless I am mistaken. I would actually like to go 4S just for the hell of it, but neither of my trucks can handle 4S.

TheyDontWantMusic

for any off road vehicle, even for on road speed runs, you'll want something in the range of 2500 - 4500kv, off 3s or 4s.

I was running a 3500kv in my firestorm, off 3s it did 100kph, so, I tried 4s, and got to 107kph (66 miles per hour) but the shell creates massive issues at these speeds, and removing it just makes it worse.

I suggest you start with a 3500kv and 3s, get to 100kph like this, and see what the truck does at those speeds!

TheyDontWantMusic

The motor will handle 4s, for short speed runs,

if the esc can't handle 4s, get a $50 hobby king 100amp esc

theunleet

I don't have 3S or 4S Lipos yet. That will be my next HK order. Possibly thishttp://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11939TURNIGYnano-tech6000MAH 3S 25~50C LIPO PACKorhttp://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11940TURNIGYnano-tech6000MAH 4S 25~50C LIPO PACK

Any idea if the new nano-tech stuff is good? I bought a 5000mAh 2S1P hardcase pack and LOVE it.

TheyDontWantMusic

if you're aiming for speed, a 2s lipo, and high KV motor isn't the right way to go about it.

theunleet

I am aiming for HIGH on-road speeds, but then be able to bash it around in the yard and elsewhere.

TheyDontWantMusic

then you need a 2500 - 4500kv motor off 3-4s

guver

My Feedback: (325)

Plug the numbers into here along with desired speed and do it anyway you want. Low voltage x high kv or low kv and high voltage. Or a little of both.

http://www.scriptasylum.com/rc_speed/_top_speed.html

nitrosportsandrunner

you can get a lower KV motor, but gear it up much higher and run it on 3s lipo. the vxl system can get your traxxas upto 75mph with the max gearing and a 3s lipo.
and if you want to do high-speed and run off road the a low KV motor is the way to go. just change the size of the pinion gear. a 18t pinion on my vxl will get me 35mph even in the grass without overheating anything. but then i can put on a 25t pinion for much higher top speeds on the street. i have never even bothered to put on the smaller spur gear. my rusty does alittle better than 50mph with a medium gearing and thats plenty of speed for me.

ScottStaypuff

Just get a good 3s lipo with the VXL motor and it'll go faster than the truck can really handle...

HRCules77

My Feedback: (4)

My $.02:
A motor with more poles will give you more torque. So if you have a couple of motors with the same KV rating and one is 2 poles while the other is 6 poles, the 6 pole motor will have the greatest torque.
I think it would make sense to choose a *lower KV, higher pole motor for your application. The lower KV would do well for keeping speed manageable on the dirt and you would have plenty of torque. The greater torque would also enable you to gear up for on-road if you like, without excessive worry about over-gearing. Of course, you will still need to pay attention to motor temperatures as a final rule. So if you are looking for a motor to drive on-road and off-road, a low KV, higher pole motor may give you the most flexibility when it comes to a greater range of gearing for performance within the different environments you mentioned while keeping the voltage the same.

*By lower KV I don't mean excessively lower. I would stay close to, but still lower than, the recommended KV rating of a 2 pole motor for your specific vehicle. Most vehicle specific KV suggestions are for 2 pole motors.

Slo-V Flyer

Actually what you are saying is half accurate. A 2200 Kv 2 pole and 4 pole motor will have the exact same torque. It is the amp draw they can handle that will determine the torque, hence the term "Kt" or torque per amp also part of a motor's specs (though not commonly noted in many r/c motors). It just so happens that the Kv rating is mechanically and inversely related to torque. So you could have a 6 pole motor and 2 pole motor that are both 3500 Kv, that pull the same # of amps for example, they will both have similar torque. However of the two, if one heats up more with the same gearing, you know that one is pulling too many amps for its size/design, and is being overloaded.

Here are 2 very common examples. My Feigao 7XL 2-pole motor (36x75mm size) is ~2300 Kv and rated to handle about ~94 amps max. That means at that amp draw, it is able to put out about 53 in-oz of torque. Similarly sized Medusa 36-70 motor 2300 Kv is rated for a maximum of 118 amps, which gives you a torque rating of 69 in-oz. On top of that the Medusa happens to be more efficient in design so it can put more of that power down to the wheels instead of converting it to wasted heat, without getting too complicated.

The reason a multi-pole motor is better and preferred however, is because it is more smoother at putting out power. That is due to the increased rate of "commutation" or switching, of the motor's wire coil polarity (the "poles") since there are more of them so the rotor turns in more "controlled" smaller increments. Think of it as having a smoother powerband.

Your part about using a low Kv motor for off-road is correct. It is generally more manageable. Also a 4 pole motor (such as Neu, Medusa, Aveox etc.) will put this power down better than a Hacker 2-pole motor would so you don't get that uncontrolled unpredictable burst of power as much.

FieroMan121

My Feedback: (2)

yeah and if you havent even seen the vxl on 3s than i would hold off on dumping more money into it, i ran my srt a few weeks running a vxl w/ 3s pack geared 24/83 and ill tell you what, that sucker moved! it squated for a seconed as the slipper wound out and then the car floated by, idk how fast (ill ball park it at 55+) and its a beast to handle, the amount of actual tire on the ground is minimal so the slighltest thing can upset it (thats why i say floated), its insane. then the next day, same gearing on 2s i went and spanked some t4's at the track, 3rd in the heat and 1st in the main

good example of how the cars goes at its limits http://www.youtube.com/watch?v=vVtK_...eature=related