Viper R/C Copperhead ESC & VX4.39 4-Pole 540 Sensorless Brushless Motor Combo (3900kV)

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This is the Viper R/C Copperhead ESC & VX4.39 3900kV 4-Pole 540 Sensorless Brushless Motor Combo. The Copperhead ESC is small and offers the smallest foot print to power ratio of all the speed controls currently on the market. The Copperhead can be used in 2WD applications with VX4 4-Pole motors, but has been optimized to perform the best with VX4R 550 class 4-Pole motors in 4WD short course trucks. It comes preloaded with 5 factory preset profiles, allowing you to easily select the profile for your driving conditions, from high speed to just learning. Plus, the Copperhead features ProGauge programmability so you can easily change the parameters of the speed control to suit your needs. Additionally, all Copperhead ESC's have factory installed high capacity bullet connectors, providing easy installation and removal for cleaning and maintenance.

The VX4 540 4-Pole Brushless motors are designed to make maximum power and torque! The VX4 motors are a great choice for high speed runs in 2WD vehicles, and have been proven to deliver the power you are looking for with the reliability you demand. Plus, the combo is complimented by Viper's 180 day limited manufacturers warranty for peace of mind.

VX4R.45 Motor Specifications:
Motor Size: 540
Shaft Diameter: 3.17mm
kV: 3900kV
Poles: 4
Sensorless: Yes

This product was added to our catalog on January 30, 2012.

Lee Phillips
Verified Owner
GREAT! Ran this system in my SC10RS w/ 20T/48. Fastest truck at the track. No problems with it. Just getting back into the hobby so I wasn't comfortable with spending alot of money but with this type of performance, i really don't see why people do. Key to this hobby>>>>>RESEARCH FIRST!
Verified Owner
Bought this based on all previous reviews to install in my RC10 B4. Ran 3S and 2S and this combo is pretty amazing. Buggy is pretty insane running 2S, 3S it had to be screaming over 60MPH on road 3S was way too much for the track. ESC and motor are very well made and pretty sexy looking as well. Great job, Viper!
George Wheat
Verified Owner
Way too much power for my Rustler, and i love it! Super easy to setup and change modes. Only thing i don't like about the system, i'm destroying my Bodies with no wheelie bar. It's a true Torque Monster.
Jacob Castleman
Verified Owner
My first thought of this combo was hfs the power was grate the brakes were ok and for only 100$ you will not beat it I would recommend this to any one. This was a perfect fit for my sc10 truck. The only thing I don't like about this combo is that it's loud so if u by this don't be alarmed it fine you will not regret buying the setup best bang for the buck you will find. It's good for the track and grate for bashing it has no temp problems on 2s lipos
james mims
Verified Owner
This combo is fast and smooth will be buying the 5150 kv next week!
Chris Elson
Verified Owner
Very strong and worth the money. I put it in my son's torment and its smoking fast only on the 2nd esc setting. I'd definitely buy another viper.
william king
Verified Owner
Excellent product I installed it as a replacement for my velinon system that went bad on a 2wd slash. with the 23 tooth pinion and 3s lipo its unbelievably fast. And has excellent brakes much more precise than the velinon which always wanted to lock up on hard stops. On the stock gearing I can balance the truck on two wheels until I run out of road. Great price for a great system. Had one Small issue with setup the polarity was reversed on the motor simply swapping only two wires to the esc fixed it or by using a pro gauge
Dustin Hamilton
This combo is bad a**!! Run's just about as smooth as a sensored system. Buy it, try it, love it!!
Joseph Dorsey
Verified Owner
Just purchased this system a little over 2 weeks ago and so far i love it. I put it in my Stampede 4x4 with a 9t RR Pinion and 54 spur amd on 2s it has tons of torque and runs about runs between 38-40 mph and on 3s its amazing as well it runs around 45-48mph with same gearing. In my eyes as of right now this thing has just as much if not more punch and speed than the Traxxas VXL System lipo for lipo. plus it runs 30-40 Degrees cooler than the Vxl Systems that cost $90-$100 more than this system. ive ran it 4-5 times on everylipo i have available and it has performed just the way i wanted it too, there is no problem with the LVC on this system where I have had nothing but problems with the Vxl systems. Overall I would reccomend this item to anyone who asks me about it. The Castle Creation motors love to burn up just by pluggin lipo in it, I am not a fan of Castles overpriced products I would choose Viper and Traxxas Systems over Castle any day!
Brian Burbank
Verified Owner
Bought this for my daughters blitz ese. Thought it would be rough for her to start it off at a stand still and not spin the tires with it being sensorless. I was impressed. First time I drove it I was surprised for the power and speed this setup smoothly delivered. Great price and product so far. Right around 10 packs through it. No heat issues. If she happens to not stick with racing ill be keeping it for my own ride. Thanks viper for making a great product affordable.
Chris Blalock
Verified Owner
This was my first after market motor and esc other than Traxxas stuff. I was really impressed after I got my radio adjusted correctly. I put it in my new B5, the esc is a little big for this buggy but it fits with a little cramming. Other than that it performs really good, almost to much power for the track I run on. I would recommend this to anyone on a budget build like I was.
luke mickell
this is by far one of the best systems i ever had way better than the traxxas vxl system this this makes my rustler flip onto its roof with a 8.4 V nimh battery pack and with a 3s i had no tires left it is an awesome system i would recommend it to any one who wants to go brushless or has a traxxas vxl system
Bought this as a cheap BL system for my Traxxas Rustler and was very pleased with the performance. Previous comments about noise are spot on and my Rusty whines like crazy but its very fast and stays very cool even after hard bashing sessions in loose gravel. I don't have a GPS or radar to track my speed but if I had to estimate how fast it is on 2s with stock gearing, I'd say in the 45mph range. Set up is easy, and for the money the overall build quality is fantastic. It is sensorless so the low speed range is relatively unrefined, but proper throttle control remedies this easily. I highly recommend this to anyone looking for an inexpensive transition into a brushless setup.
Rylie Carter
Verified Owner
This combo is very very fast...ran a 6500mah straight and this thing is ice cold son and I ran this with big smiles on our faces....for $99 this viper combo is solid and screams quality ...I still have to hook it up to the programmer and I am sure it will make this combo even better
Russell KOTZUR
Verified Owner
Works great in xxx sct, in fact had to turn throttle epa down because it was too fast for my skills at full speed.
Verified Owner
I have to date run this system for about 2 hours run time. Took out brushed system put this in, kept everything the same and hit the dirt....power compared to old system was enough to blow a was great!(although some down time putting tyres back on) ESC is large and just fits into SC10 where the ESC goes, but I mounted mine on top of the battery tray with some zip ties to even weight out a little. ESC is easy to use even without programming card, but I will get one at some stage to fine tune. Seems to add some over steer to the truck so must be heavier then I am use to but that is easy solved. Extremely happy to date and a great price point on this system compared to comparable other manufactures system.
Steven Bittick
Verified Owner
Plugged it in and it burned to the ground, almost took my Wraith with it, it did however melt my Spektrum receiver. STAY AWAY!!!!!
Ryan Coombes
Verified Owner
Performance on 3s was quite poor, tested in a Savage XS on the same gearing I tried this system (3900kv 4 pole) back to back with the traxxas Velineon (3500kv 2 pole). The traxxas system had more punch, more torque and a higher top speed. The brakes in the copperhead are aweful as well, unless you have the tuning gauge you cant get enough brakes, the first 4 profiles all had poor brakes and if you like to pulse the brakes on and off the copperhead thinks you want reverse and will trow it into reverse, not very helpful. Conclusion is, im selling it, probably replacing it with a castle system, it might cost a bit more but its worth it.

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