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Old 04-12-2006, 07:33 PM   #1
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Default Reading Fantom Dyno #'s????

I know I know, get a CE or Robotronics Just wondering what guys who have and use this dyno have come to look for to determine what a "good" motor is to them? I just got a Fantom dyno in trade for some other RC stuff and was trying to put it to use. Do you guys look for the highest wattage? Torque? Eff??? Here's a sample of a new Komodo I just finished with a couple different spring combos

37/67/68 158.41 watts @9994 Max Rpm 15689 @1.20secs 2.93tq 45%eff
32/75/80 149.15 watts @12775 Max Rpm [email protected] 1.37tq 77%eff
31/74/81 146.13 watts @13449 Max Rpm [email protected] 1.30tq 79%eff
34/70/72 141.57 watts @10275 Max Rpm [email protected] 2.13tq 51%eff

Thank you in advance for any help
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Old 04-12-2006, 08:55 PM   #2
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Honestly, you need to look at the curves on the graph. You can compare powerband widths and such a lot better. You can also check out the time base view to get detailed numbers. Hope this helps.

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Old 04-12-2006, 10:08 PM   #3
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I don't own a Fantom dyno, but I've used them a lot at oval races...

The biggest 'secret' is that the numbers that come up on the screen right after a run are (or can be) misleading. Peak RPM comes at a different point that Peak Power, and/or Peak Efficiency -- many oval racers have a motor they use as an example of a motor that "fakes out" the dyno on these numbers -- the numbers look "killer", but the motor is a POS on the track...

Jeff is right on -- you need to look at the power curve.

Even if you only have the original DOS software, you can look at the data on the timeline to see how the motor builds and maintains it's power... look at the number in the 20-30 amp range to get a feel for how the motor will perform under real world use...
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Old 04-13-2006, 03:03 PM   #4
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Thanks guys Anyone else?
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Old 04-13-2006, 03:20 PM   #5
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What they are telling you is right.

To help corolaote teh data you are seeing think of Watts has HP, torq as punch and RPM as top end.

More watts is more power, torq and RPM readins just tell you where the power is coming from and how you will need to gear it.

What you are looking for in a good motor is one that produces the most watts in the 20-30A with a linear torq and RPM cuve in that range for stock and 19T motors. You may also want to check the spool up times, A motor with a little more power but a longer spool up time may be good for tracks with longer straights but will feel a bit sluggish on more technical circuits.

With this type of dyno I would suggest that you use the data provided as more of a guide to weed out bad motors and compare your better motors on the track to really see whats what.

Mark
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Old 04-13-2006, 08:27 PM   #6
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Quote:
Originally Posted by tfrahm
The biggest 'secret' is that the numbers that come up on the screen right after a run are (or can be) misleading.
Actually, we have found the numbers after a run help to make the motor finish stronger. You can compare before and after numbers and see how the motor holds up. Ultimately you need to finish strong to finish first and no better way to check than off the track. We used to try and dyno motors after a run as they were still warm.

Dyno numbers before a run are good, to keep a baseline and make sure the motor is maintaining performance. The motor after a run I think tells you more about how the motor holds up and you can change setup and/or gearing to finish strong. Just my opinion though.

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Old 04-13-2006, 09:18 PM   #7
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Jeff -- What I meant by "after a run" was after a "run" on the dyno -- the summary numbers that come up automatically on the screen immediately after you spin up a motor on a Fantom...

As to dynoing a motor after a run on the TRACK -- I agree totally. I've seen guys cut a fresh comm, etc. and then cool the motor (even put it in a fridge) before they dyno it. That always seemed silly to me -- our motors reach "operating temp" (say 110-150 degrees or so) probably within the first 30 seconds of a run. "Cold" numbers are meaningless on any dyno. The more you can test the motor under real world conditions, the more accurate your information.
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Old 04-13-2006, 09:32 PM   #8
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Quote:
Originally Posted by tfrahm
Jeff -- What I meant by "after a run" was after a "run" on the dyno -- the summary numbers that come up automatically on the screen immediately after you spin up a motor on a Fantom...

As to dynoing a motor after a run on the TRACK -- I agree totally. I've seen guys cut a fresh comm, etc. and then cool the motor (even put it in a fridge) before they dyno it. That always seemed silly to me -- our motors reach "operating temp" (say 110-150 degrees or so) probably within the first 30 seconds of a run. "Cold" numbers are meaningless on any dyno. The more you can test the motor under real world conditions, the more accurate your information.
Exactly.

Jeff
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