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Old 06-15-2012, 12:54 AM   #1
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Default Timing (motor/ESC) vs. Gear ratio

I need some serious help or some expert opinion when it gets to achieving top speed without heating up the motor too much. I'm running mod!

Is it better to work with Timing (motor/ESC) or lowering the gear ratio? What will get the motor hotter when you make more timing (motor/ESC) or lower the gear ratio to get the same top speed and how does it affect the torque/bottom power?

Thanks for any advice!
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Old 06-15-2012, 03:09 AM   #2
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Depends on the motor you are running. Some motors do have more torque than the other and benefit more from lowering gear ratio. A motor which is better in the higher RPM area benefit from more timing.

You should just test this.
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Old 06-15-2012, 05:05 AM   #3
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I'm running a NOSRAM Pure/LRP X12 4.5T motor with 12 mm rotor on a big track 6 min run. Boost (min) and Feel (min), gear ratio 8,0 motor temp 100 degree. But still too slow. Should I go to a 4.0T but the problem is 5500 Reedy LiPo capacity ...
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Old 06-15-2012, 08:15 AM   #4
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you still have alot of motor left. ive read that timing is a fine tune adjusment. get it with the gearing first then add timing. you want your motor to be around 140-150 on the heat side. so if your at only 100 and need more speed try to go up 2 teeth. run it for 2 mins and check the temp. if its around 100 then you should be good. if its way higher then it was to much change.
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Old 06-15-2012, 08:34 AM   #5
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Is that 100 degree C or F? If it's Fahrenheit, than svr is right, if not, better get cooling the motor down.
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Old 06-15-2012, 09:20 AM   #6
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Guess thats Celcius ;-). X12 doesn't like boost that much, btw.
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Old 06-15-2012, 10:06 AM   #7
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Quote:
Originally Posted by dennisV View Post
Guess thats Celcius ;-). X12 doesn't like boost that much, btw.
Yes it's 100 Celsius, not Fahrenheit!
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Old 06-15-2012, 10:06 AM   #8
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Quote:
Originally Posted by dennisV View Post
Guess thats Celcius ;-). X12 doesn't like boost that much, btw.
kinda figured that as well... otherwise he wouldn't be concerned
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Old 06-15-2012, 09:16 PM   #9
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That's way too hot! It seems that your setup of gearing vs timing Isnt running efficiently to be getting that hot, your motor
Is slow because it's getting really hot!
The x12 is a very torquey motor , try gearing it abit lower and see what happens
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Old 06-15-2012, 09:33 PM   #10
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What timing insert in the motor? It had better be the -10 one.
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Old 06-18-2012, 11:12 PM   #11
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Quote:
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What timing insert in the motor? It had better be the -10 one.
I was running one dot (+5 degree) now I will go to three (-5 degree) or even four dots (-10 degree). I hope this will help.
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Old 06-19-2012, 07:26 AM   #12
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Default gearing vs temp

I try to gear any motor in blinky 1st. I know the temps in F*, I know rude american. I try to gear on a nice hot day, 160 F and then you can drop a tooth for every 5* degrees of timing or you'll get way hot. As you said, you need a really good battery to pull something that deep in wind. I haven't found tires the likes our high heat in the midwest on asphault. My Xray is really fast with a tekin 10.5/35*T and 20% boost. I'm not good enough to handle more car then that. You can go one tooth beyond the 160 point, and the motor will come down a bit, but the esc goes up fast. Hope I didn't blur things worse, if you can afford 64 pitch, it's easier to fine tune it. I only use it on road and not on the dirt, doesn't matter as much, traction is more important on dirt as slick is much harder to gear for, but what an equalizer.
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Old 06-19-2012, 12:04 PM   #13
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I don't know much about modified motors and their operating temperatures, but when my LRP/NOSRAM 10,5T stock motor (open boost, speeds close to mod) got a few runs in the 100+ degrees Celsius zone, one of the 3 phases on the motor melted (very hard to explain in my non-native language, sorry!), which resulted in the motor not starting at all (you need to turn it by hand and then it will run). This came after one of the 2 fans stopped working which I didn't notice at first since my mechanic/father was not home that week so he couldn't measure the temperature instantly, which meant I had to measure it coming from the drivers stand, and it's a bit of a walk to the pits which meant the motor was in approx. 20 seconds of cooling airflow which when I came to the car resulted in 100 C (it probably operated in 110+), which a young engineerig student like myself descibed as "meh, it's a hot day..." Anyway, the point is, lower the ratio (smaller pinion), the motor will be much cooler, you will use less mAh and it seems to me the car is even braking a little better. If too slow, you can always add a bit of boost/turbo.
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Old 06-21-2012, 08:41 AM   #14
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OK. I gotta put something on here too.


BLinky: Time for Power, Gear for the track. If your lucky enough to ahave a dyno, spend a rainy day doing some pulls. Figure out where _YOUR_ motor and ESC like to run. Changing even the rotor will change the motor dramaticaly. Once you get to the track then you can gear it accordingly. Remember though, you dont need to be fast on the most track straights, 70% of the course is in the infield and corners.

Boost: Same idea, I boost the heck out of my motors to have the lowest end bell timing. Keeps the motor cooler, and makes the most torque. Then gear to the track. Wish I had a DAC system to measure the motor in real time though. Maybe next year.


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