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Old 02-23-2015, 08:11 PM   #1
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Default Fan and heatsink or just fan?

Have a Sakura running a 13.5 and my temps do get up a bit in the warm weather. Have a Yeah racing 30mm fan running and it helps but is it worth putting a heatsink or as well? Looking at a few other cars at the local track and hardly anyone uses them (but they all have fans).
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Old 02-23-2015, 08:15 PM   #2
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Have a Sakura running a 13.5 and my temps do get up a bit in the warm weather. Have a Yeah racing 30mm fan running and it helps but is it worth putting a heatsink or as well? Looking at a few other cars at the local track and hardly anyone uses them (but they all have fans).
just a fan, but look at getting something stronger then the Yeah racing ones, or run them off the battery.
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Old 02-23-2015, 09:39 PM   #3
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Ok thanks
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Old 02-24-2015, 02:27 AM   #4
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Only problem with a fan on it's own is that the airflow only occurs in one direction.
If you combine it with a heatsink, as it wraps around the motor more you may find it can dissipate the heat more evenly.
Best thing might be to try both and see what it does to motor temps.
Remember to measure the temp inside the motor through the holes as well, as this can sometimes be quite a bit higher than the outside.
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Old 02-24-2015, 06:18 AM   #5
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IMO, depends on what kind of heatsink you have and how the fan blows to the motor.

Personally I don't like the large clip-on heatsinks that wraps around the whole motor, I think its only as efficient as the area, more importantly the quality of the contact, as worst case if the shape between the can and heatsink arc aren't matching the only contact area is probably only three points around the motor can: two ends of the clip and at the center of the clip arc. The remaining area is likely just a thin gap of air or just poor contact.

Probably better to mount the fan in a way that it blows directly onto the can surface, while the heatsink faces another direction away from the fan (instead of the fan mounted on top of the heatsink).

Of course, what better way to compare than to test in reality.
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Old 02-24-2015, 06:58 AM   #6
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IMO, depends on what kind of heatsink you have and how the fan blows to the motor.

Personally I don't like the large clip-on heatsinks that wraps around the whole motor, I think its only as efficient as the area, more importantly the quality of the contact, as worst case if the shape between the can and heatsink arc aren't matching the only contact area is probably only three points around the motor can: two ends of the clip and at the center of the clip arc. The remaining area is likely just a thin gap of air or just poor contact.

Probably better to mount the fan in a way that it blows directly onto the can surface, while the heatsink faces another direction away from the fan (instead of the fan mounted on top of the heatsink).

Of course, what better way to compare than to test in reality.
I agree, that's why it's important to get a decent heatsink.
I also use heatsink compound between the stator and the can and some more between the can and the heatsink.
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Old 02-24-2015, 07:18 AM   #7
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Heat sink compound??? Here is my solution. Its a superior hobbies F5 with a lexan shroud ontop and side to direct air straight onto the motor. It is wired to run straight off the battery. Motor temps drop by 20deg or more with it.

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Old 02-24-2015, 08:10 AM   #8
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Are you all using fans to push air on to the motor?

I always believed they were used to pull the hot air away.
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Old 02-24-2015, 08:17 AM   #9
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Better for weight distribution if you have the fan in front of the motor blowing over it (or over the heatsink and motor in my case )
Also more efficient having them blow over a motor instead of trying to get them to pull the air across it.
If it's behind the motor and blowing over it you're also trying to push air in the opposite direction to any underbody airflow.
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Old 02-24-2015, 08:29 AM   #10
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If your putting it infront of motor, how are you not on the motor, where do you have space between the esc and motor? The fan needs a few mm of space to be effective in any direction. And if its betwen the esc and motor aren't you just drawing warm/hot air off the esc to blow on the motor.

I put the shrounds on the motor to ensure the air blows directly on the motor. The force of that fan with directed airflow is far greater than the force of turbulent air moving around inside the body. If there were that much airflow under the body to counter a fan, we wouldn't really need fans would we?

On my VBC putting the fan behind helps me get a better chassis balance. My cars are weighted to be within 10g front/rear and dead even left/right.
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Old 02-24-2015, 09:12 AM   #11
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Quote:
Originally Posted by daveaustin5 View Post
Are you all using fans to push air on to the motor?

I always believed they were used to pull the hot air away.
For a fan to draw heat away instead of blowing, the motor needs to be in a more enclosed environment for it to be effective (creating suction).

My 0.02
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Old 02-24-2015, 10:52 AM   #12
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I did a quick test on the asphalt track here last summer with my 17.5 TC. I did a run with my Xray T3 with an Associated TC4 heat sink on the motor with heat transfer compound between the two. Temp was about 160F. Next heat I took the heatsink off and lost about 15g, but my temp went up to about 175F. I put the heatsink back on and geared the motor up.
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