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Old 05-15-2007, 03:46 AM   #1
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Default Motor dyno readouts.

Id like the more experienced guys and pro's to please explain what we should be looking for on a motor dyno read out to help us make a decision if motor is good ,is suited for short gearing or long gearing ,or basically to know which is better.
Obviously there is factors that influence read outs between brands and models etc... but i am looking at it if choosing from a number of x brand motors of the same model.

example of 2 read outs from CO27 stock motors:
both at constant voltage of 7v

Motor 1
rpm torq watt Ef amps
26444 3.8 75 59 18.1
24846 4.8 89 63 20.0
22913 6.1 104 67 22.1
21462 7.0 118 67 25.1
19658 8.0 129 65 28.2
18637 9.7 133 62 30.2

motor 2
rpm torq watt Ef amps
29293 3.2 70 55 18
28269 4.0 83 59 20
26947 4.8 95 61 22.1
24693 6.2 114 64 25.2
22483 7.7 129 65 28.2
21279 8.6 135 63 30.2

What are the key properties to look out for ie: rpm vs torque or rpm vs wattage ,etc...
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Old 05-15-2007, 08:24 AM   #2
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Default moto dyno

when reading dyno # for 1/12 scale I look at the perform ance in the 20.25 amp range watt output being the 1#.
I find most people look ant the rpm as theis reference.that is # tree behind watt and torque
tha way I calculate gearing using the CE is eace first yuo have to have a good stocker motor at a certein track to be a standard to go by. say you have a fast trinity monster the dyno reads 102 watt a 20amp load and your gear for your track was 4.00 the rpm at tha load was 21.000 now you have a trinityco27 but the rpm is only 18.202 at the same 20 load. what do you gear

well first divide the ratio that you use with trinity monter into the rpm (21.000/4) that gives you a # of 2550 this is your control # for stock motors at this track.

now take that control # (5225 an divide tha in rpm of your new trinity co27 motor to equal the seme speed (if tire size remmains the same) 18202/5225= 3.47 this is ration you should run the trinityco27

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Old 05-15-2007, 08:51 AM   #3
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They both have similar power, but the first one is a torquey motor, meaning you'll want to use a bigger pinion on that one, whereas the second one is a lot revvier, needing a smaller pinion.

If you look at the Power output, i.e. watt provided, they're both really similar, but will provide their power really differently.
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Old 05-15-2007, 10:18 AM   #4
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Another thing i noticed is that all these readouts on new motors are done with new brushes and from a few i had a look at ,they didnt have the brushes broken in properly.From this wouldnt you think the info would be misleading or not indicative of what the motor is capable of.Surely when the brushes are bedded in properly they would have different readings.
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Old 05-15-2007, 11:11 AM   #5
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Quote:
Originally Posted by razzor
Another thing i noticed is that all these readouts on new motors are done with new brushes and from a few i had a look at ,they didnt have the brushes broken in properly.From this wouldnt you think the info would be misleading or not indicative of what the motor is capable of.Surely when the brushes are bedded in properly they would have different readings.
when you get a fresh motor off the dyno and you get a print out ,the motor is going to have different #'s once you run the motor 1 time, after you run the motor once you might as well and throw away that dyno print out.
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Old 05-15-2007, 11:54 AM   #6
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I got a few motors that i wanted to compare and i took out one that i ran on the weekend.stripped and cleaned it and then compared the brushes on the new motors hence my post above.
From what ive seen the dyno info would then be useless seeing that the brushes are still new and not bedded in yet.
The info would be usefull if the motors were run in or dynoed after a run or two.
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