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Best 17.5 Motor For 2017 TC?

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Best 17.5 Motor For 2017 TC?

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Old 06-07-2019, 11:31 AM
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Originally Posted by Marcos.J View Post
would be nice to see some of Nicks testing at the track instead of a bench i had motors with great numbers and turn out to be crap on the track
Well then Nick would need to send every motor to his local racers for testing: no way he could test them all by himself.....Let's be realistic and kind to an old man that did alot more for us than any other man half his age......I know lots of racers have used the track as a dyno, but failed to have a thread to post their findings for all to see, and then criticize those that share what they have discovered...WOW.....Keep up the good work Nick !!!
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Old 06-07-2019, 11:38 AM
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Originally Posted by bertrandsv87 View Post
Well then Nick would need to send every motor to his local racers for testing: no way he could test them all by himself.....Let's be realistic and kind to an old man that did alot more for us than any other man half his age......I know lots of racers have used the track as a dyno, but failed to have a thread to post their findings for all to see, and then criticize those that share what they have discovered...WOW.....Keep up the good work Nick !!!
dont believe in the 6 amp myth thats all
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Old 06-07-2019, 11:40 AM
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It's not that people aren't posting to keep things a secret.... Every motor, every tuner, every Racer has different methods. Pretty sure that's the general conscious these days, no matter the motor you need to dial it in to extract the best outcome of power,run time and heat... seems in 2019 most people know this by now. Some guys like higher FDR with more timing / amp draw others lower FDR with less timing and am draw or half way in between, different track layouts, different surfaces etc. You can post 20 dyno videos and people will still have different opinions and methods to what the person is doing in the video versus the track they are racing at.

Nick does great for everything available to him for sure, but until you hit the track all those dyno numbers are just hype. On any given race day at almost every club I'm sure there are 2-4 different motors in the top of the main. There isn't a point of yapping 30-40 pages about motors when truly it's much more then just that to go fast over 6 mins.
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Old 06-07-2019, 01:13 PM
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Originally Posted by Marcos.J View Post
dont believe in the 6 amp myth thats all
I don't ... I leave my motors the way they came from Fantom and just gear them while trying to lose as much rotational mass as possible....
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Old 06-07-2019, 08:44 PM
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a dyno is like a ruler. It provides a way to accurately measure and reproduce. i build race cars and tune them and there is a tendency for people to build dyno queens that are un-driveable. I dont see it in RC. I see the opposite.

What happens in RC is people test and tune on track and dominate or struggle. The guys struggling dont understand or maybe dont have the patience for FDR/time and heat. Allot of guys want to repeat someone’s or there own results by using a motolyzer. Or they are just trying to get a starting point. None of this is wrong. You either invest in the on track tuning or hope for the best and get varied results.

You have to do 3 things as it relates to motors that require language or time. Find the motor with the most power or power you are comfortable with. Find where the peak of power and efficiency are at. Lastly you have to adjust the car to use these two peaks.

Ive seen 17.5’s range from 125 watts to 600 watts. That is a big difference.
the peaks can be very narrow and sharp or very wide and shallow.
lastly the ability to understand how average rpm and power to pick the right FDR to keep the motor in the peak only comes from a stopwatch or an understanding of track speed or a dyno.

KV doesnt really help until you know far more about electric motors and it has limited use in stock classes. The motolyzer has good info but you cant use it as science until you understand the below and can do some combination of the below fluently.
current=torque
rpm=track speed
Otherwise spend time with the clock

every motor, every track, and every preference creates allot of variables.
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Last edited by Bry195; 06-08-2019 at 06:13 AM.
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Old 06-13-2019, 08:10 PM
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Originally Posted by bertrandsv87 View Post
I don't ... I leave my motors the way they came from Fantom and just gear them while trying to lose as much rotational mass as possible....
https://www.motioncontroltips.com/fa...oes-it-matter/

you have been playing with inertia matching and I found this basic description of the benefits and detriments of inertia management. if your route to speed has you looking into the science then this will give you a how but not a clear why.

if the science of electric motor control is your bag their is a prerequisite before you can master inertia from a science perspective and it comes in stages.

1-like real race cars power is king. 400 watts is twice as much work as 200
2-understand what you are looking at when looking at a power curve. its a bunch of discrete roque and rpm points instead of a peak.
3-understand the torque requirements for a tracks acceleration and decelerations.
4-understand speed or what the average speed requirement is to do a lap in x time.
5-understand peak efficiency so that you dont get fade
6-inertia ratio-the single biggest difference between combustion engines and electric motors. This is the single subject that has the largest impact but is not intuitive to engineer minded combustion trained people. Electric motors accel and deceleration is the biggest impact on how they work and matching inertia ratios is a little more complicated than having a geartrain that is half the inertia of a rotor. Efficient but powerful geartrain control is a tight balance of heat and power.
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Old 06-14-2019, 05:15 PM
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Test and tune is always the best way to find more track speed, but I feel the same should apply for slightly higher inertia rotors...I know muchmore has already tested the lower inertia titanium shafted rotors(22.2g/high rpm+low torque), but nobody has tested the other end of the spectrum yet, where I think the motors will develop enough extra inertia to move the tc cars faster down the track, eventhough they might theoretically take more time to accelerate on the dyno...
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Old 06-14-2019, 07:52 PM
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Originally Posted by bertrandsv87 View Post
Test and tune is always the best way to find more track speed, but I feel the same should apply for slightly higher inertia rotors...I know muchmore has already tested the lower inertia titanium shafted rotors(22.2g/high rpm+low torque), but nobody has tested the other end of the spectrum yet, where I think the motors will develop enough extra inertia to move the tc cars faster down the track, eventhough they might theoretically take more time to accelerate on the dyno...
with the advent of neodymium magnets people got really happy about torque density. allot of people forgot about ferrous core magnets until they have an inertia problem. for a dynamic start stop application its better to have the goldy locks ratio than to have 50 percent more torque or power.

i suspect the same as you about lowering the inertia ratio through increased rotor inertia and decreased mech inertia but its just a suspicion. low inertia ratios for accel and deceleration and high inertia for continuous power. do a time trial that is repetitive accel and deceleration.remove the dif and see how the times respond. if your not traction limited you can test the effects of inertia.
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Old 06-14-2019, 10:14 PM
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Originally Posted by Bry195 View Post


with the advent of neodymium magnets people got really happy about torque density. allot of people forgot about ferrous core magnets until they have an inertia problem. for a dynamic start stop application its better to have the goldy locks ratio than to have 50 percent more torque or power.

i suspect the same as you about lowering the inertia ratio through increased rotor inertia and decreased mech inertia but its just a suspicion. low inertia ratios for accel and deceleration and high inertia for continuous power. do a time trial that is repetitive accel and deceleration.remove the dif and see how the times respond. if your not traction limited you can test the effects of inertia.
I did test lowering my drivetrain inertia by cutting 52grams off , and the acceleration difference was very noticeable, but now I've reached the point where the motor's rotor is the last piece left to investigate by going either low(22.2g)/mid(27g) or high(40g) inertia...So far I only have tested mid motors, but have heard lots of disappointments about the low motors torque output...Knowing the Rc world, I can already see folks' interest peaking.......
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