# 17.5 motor wattages



## NCFRC (Aug 4, 2005)

So a lot of tracks are allowing a 17.5 motor just long as it's Roar approved.

BUT has Roar looked at the wattage differences ? I don't have them all as many manufacture's are not posting them.

I did see one company advertise there 17.5 at 165 watt where the very common SS or Ballistic is rated at 130 watts.

Any thoughts on this


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## bojo (May 6, 2002)

Thats were your power is . not by amps


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## NCFRC (Aug 4, 2005)

bojo said:


> Thats were your power is . not by amps


I understand that ,, So how is a class that allows any 17.5 motor NOT going
to fall victum to the motor of the week deal ?

It wasn't so bad when you could buy the latest brushed motor for $30-$40.
Now a custom build with bearings and spec. sheet is $120


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## ta_man (Apr 10, 2005)

NCFRC said:


> So a lot of tracks are allowing a 17.5 motor just long as it's Roar approved.
> 
> BUT has Roar looked at the wattage differences ? I don't have them all as many manufacture's are not posting them.
> 
> ...


Advertised wattages on these motors don't mean much. Esspecially since it frequently isn't clear what they mean by the watt rating. Too many people think that because a motor is ratted at "X" watts, they will always get "X" watts out of it no matter what the circumstances. (I've lost track of how many times guys have said they expected 890 watts out of an HV4.5 on 2S LiPo when Novak rates that motor at 890 watts on 14.4V.)

Novak ratings, for example, are continuous output at 7.2V for 6 minutes. It is strictly a heat dissipation issue. Neu, for example, might rate a motor at 1000 watts continuous and 2000 watts surge. Is it a 1000 watt motor or a 2000 watt motor?

So that 165 watt rating might be for 4 minutes instead of 6 for the Novak. Or it might be 8.4V (peak LiPo voltage) for 1 minute. Or it might have been with a heatsink and active cooling (fan or thermo-electric). Or it might be like MaxAmps C-ratings (100C for a fraction of a second - totally useless information, except as marketing hype).

Comparing wattages from different manufacturers is like comparing grapefruit and footballs. Yes, they both have a round cross-section (assuming you slice the football correctly), but that's about it.


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