Felony Riddle me this Batman (ESC/motor combo)

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Arrma RC's
  1. Felony
Castle has a new ESC/motor combo that looks really interesting: MMX8s with the 1520-1650KV sensored motor. At first brush, this looked good because I saw that their cryo-drive technology keeps temps down which is something I'm interested as I live in an area that gets really hot in the summer. But I read that the MMX8s was having fan issues. Not sure the percentage but some folks are having some issues. Then I was curious about how much this changed top speed... it was really a small amount. I'm not going for a 150mph speed run, just using that as a benchmark as to what would change. With the added weight, seemed that it would accelerate slower. I don't know exactly how much extra weight as there is no weight for the 1520-1650Kv motor but the ESC and batteries would be about 4.5 oz heavier on the 8s setup. It almost seems like it would be a minor change.

So it made me question why Castle would recommend this for the Felony. Don't get me wrong, this isn't a poke at Castle at all, quite the opposite really. I am probably missing something which makes this a good upgrade but I'm not seeing it. Spektrum Firma 150A 6s with 2050Kv vs MMX8s 8s with 1520-1650Kv... what is the big difference? Please educate me.
 
The higher you go with Cell count, generally the lower your KV. So the stock compared to Castle is analogous. Take 2 motors and try to set them up at the same RPMs. The lower kv motor will need more volts to match the rpms of the higher KV motor running less volts. Gearing being a constant. This is just a general rule. Can size and armature length add into the equation and it gets more technical than this. Lower Kv motors offer better torque in general yet lower RPM's. So you volt up. and gear down where it runs best. I am generalizing to help you understand it. Others may chime in with their spin. Hope this made some sense. :cool:
 
The 1717, (1650kv) vs the stock system is like comparing apples and bananas ... that castle system would be a huge jump in performance compared to stock. For one the can is massive compared to the stock 2050 can. And for two the ability to go 8s opens the door for so many possibilities.
 
The majority of the MMX8s fan issues was the blades touching the fan cover. Supposedly they have solved that issue, but for people like myself with the 1st ones that came out we clipped the upper edge of the fan blade or some added a small spacer to the fan cover. Problem solved.
As far as top speed and the fan generally the fan does not kick on till after the run is done because the ESC is slowly heating up as the run goes on. I have yet to get the ESC beyond 175 F which is very impressive compared to how the MMX6s or XLX used to preform. I am a believer in this esc and its tech.

I believe this new 1520 motor and the 1717 was marketed towards the Arrma 6s lineup. While some of the top speed runners use 2200kv on 8s for optimum RPMs, someone less experience in the hobby might install this in a parking lot car, and burn up the motor on their first outing. Castle chose this KV because it will run cooler. If someone over heats this motor in a Felony or Infraction it would mean that they geared way too high or didn't run a heatsink/fan on it on a warm day.

There absolutely is not a setup that can speedrun and bash for a full battery pack. Those are two very different gearing setups.
My personal opinion is that any setup geared for more than a real 70+mph is likely to overheat, no matter the motor size or KV.
 
The 1717, (1650kv) vs the stock system is like comparing apples and bananas ... that castle system would be a huge jump in performance compared to stock. For one the can is massive compared to the stock 2050 can. And for two the ability to go 8s opens the door for so many possibilities.
This is a newer motor, a 1520 1650Kv. It is more narrow and slightly longer than the 1717. Compared to the stock 2050Kv, it is slightly bigger diameter but a rather significant length difference (40x74 vs 41.6x88.8). As far as comparing apples to bananas, how does it significantly change the setup? Sorry, I am trying to understand the technology.

The majority of the MMX8s fan issues was the blades touching the fan cover. Supposedly they have solved that issue, but for people like myself with the 1st ones that came out we clipped the upper edge of the fan blade or some added a small spacer to the fan cover. Problem solved.
As far as top speed and the fan generally the fan does not kick on till after the run is done because the ESC is slowly heating up as the run goes on. I have yet to get the ESC beyond 175 F which is very impressive compared to how the MMX6s or XLX used to preform. I am a believer in this esc and its tech.

I believe this new 1520 motor and the 1717 was marketed towards the Arrma 6s lineup. While some of the top speed runners use 2200kv on 8s for optimum RPMs, someone less experience in the hobby might install this in a parking lot car, and burn up the motor on their first outing. Castle chose this KV because it will run cooler. If someone over heats this motor in a Felony or Infraction it would mean that they geared way too high or didn't run a heatsink/fan on it on a warm day.

There absolutely is not a setup that can speedrun and bash for a full battery pack. Those are two very different gearing setups.
My personal opinion is that any setup geared for more than a real 70+mph is likely to overheat, no matter the motor size or KV.
Thank you very much for that. I didn't see if the fan issue had been resolved, I am glad I asked. Your comment about putting a 2200Kv motor with the wrong gearing and burning it up is sort of why I have been asking more questions lately. Manufacturers like Arrma are always going to be conservative with their designs for lots of reasons. On the other end of the spectrum I see folks who push things well past redline knowing it will break stuff but wanting to push the envelope. My goal is to understand the area between conservative and redline.
 
Thank you very much for that. I didn't see if the fan issue had been resolved, I am glad I asked. Your comment about putting a 2200Kv motor with the wrong gearing and burning it up is sort of why I have been asking more questions lately. Manufacturers like Arrma are always going to be conservative with their designs for lots of reasons. On the other end of the spectrum I see folks who push things well past redline knowing it will break stuff but wanting to push the envelope. My goal is to understand the area between conservative and redline.

When the 1717 came out years ago no one really ever took that motor beyond 130. Something seems improved with this new one as guys are now going 150+ I will be watching closely to see what happens with this 1520 motor but I suspect it will under perform compared to the 1717 given the specs are almost the same but is a smaller motor overall.

Lower KV can handle big gearing, but will never have the RPMs. Bigger motors don't seem to need as much RPM to go fast. Guys are also running the Castle 2028 in the 1100kv wind on 8s in the Limitless and breaking 150mph. To do that they have to go well past the 1:1 ratio into the "negative" I have heard of some setups like 29t spur and 45t pinion.

Edit/Addition -
When your KV is higher temps will be higher as will amp draw.
With lower KV you initially will have lower temps and amp draw can reach the same as higher KV by adding gearing. In this scenario you have the control of amp draw and temps via gearing. It is not always apples to apples, but this has been proven to work with guys pushing the 1650kv motors just as fast as the 2200kv motors.
 
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This is a newer motor, a 1520 1650Kv. It is more narrow and slightly longer than the 1717. Compared to the stock 2050Kv, it is slightly bigger diameter but a rather significant length difference (40x74 vs 41.6x88.8). As far as comparing apples to bananas, how does it significantly change the setup? Sorry, I am trying to understand the technology.


Thank you very much for that. I didn't see if the fan issue had been resolved, I am glad I asked. Your comment about putting a 2200Kv motor with the wrong gearing and burning it up is sort of why I have been asking more questions lately. Manufacturers like Arrma are always going to be conservative with their designs for lots of reasons. On the other end of the spectrum I see folks who push things well past redline knowing it will break stuff but wanting to push the envelope. My goal is to understand the area between conservative and redline.
My bad, ??‍♂️didn’t realize. I thought you were referring to the 1717 which is a beast! Also, the sensored capabilities of the castle systems is fantastic and to me does not at all compare to the oem systems. I can only speak to the experience of 1515, 1717 and 2028 systems. I’ve never had any experience with what you mentioned.
 
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Yep, that is what I read before I posted this question.

I decided to call Castle and talk about this. Overall, the benefit to this package seems to be cooler running temps as opposed to what the stock Felony setup. Castle has not tested this on the Felony or Infraction so they cannot speak to fit or performance. Though the consensus is that it will fit in the stock motor position (might need a shoehorn ;) ) and that the cooler temps will allow more gearing options that you cannot run with the 2050Kv/Firma 150A ESC. Though they couldn't specify as no one has tested it.
 
Castle has a new ESC/motor combo that looks really interesting: MMX8s with the 1520-1650KV sensored motor. At first brush, this looked good because I saw that their cryo-drive technology keeps temps down which is something I'm interested as I live in an area that gets really hot in the summer. But I read that the MMX8s was having fan issues. Not sure the percentage but some folks are having some issues. Then I was curious about how much this changed top speed... it was really a small amount. I'm not going for a 150mph speed run, just using that as a benchmark as to what would change. With the added weight, seemed that it would accelerate slower. I don't know exactly how much extra weight as there is no weight for the 1520-1650Kv motor but the ESC and batteries would be about 4.5 oz heavier on the 8s setup. It almost seems like it would be a minor change.

So it made me question why Castle would recommend this for the Felony. Don't get me wrong, this isn't a poke at Castle at all, quite the opposite really. I am probably missing something which makes this a good upgrade but I'm not seeing it. Spektrum Firma 150A 6s with 2050Kv vs MMX8s 8s with 1520-1650Kv... what is the big difference? Please educate me.
Weight isn't always a bad thing. Although I only run a 3s Senton(im new), I found it runs better since I added weight with the body modification I did. Although I didn't do before and afters like I should have, I feel it accelerates faster but top speed is probably the same. Reason for this is traction. Going full throttle had it spinning out before and over-drifting. Now it darts out when going full throttle with little spin out and drifts the way I want it to, controllable. Its more about finding the perfect power/weight ratio. To little and too much would be counter-productive.
 
To my mind and understanding, the 1717 and 1520 should be roughly equal in terms of performance, if this gentleman is credible in his assessment of motor performance
. What he says and shows seems logical enough to my mind and if he's not talking hog warsch, all other things being equal you can roughly determine a motor's output by its weight (since they're both CC motors I'm going to go with "all other things being equal"). Both of these motors are in the 460g ballpark (+/-10g) sans leads. I think it's also worth reiterating that the given KV value printed on the motor is not the actual KV of the motor but is a binning value and the actual max RPM of each individual motor will be in a +/-10-15% range of it. Its possible to get a readout of the actual KV value of your motor with a CC ESC (Raz Shiffrin explains how to do this in one of his videos). My 1520 1650KV for example has an actual rating of 1320KV if memory serves.
 
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