Granite Grom Fan Options?

[rhinopuncher17]

My gf, a close friend of mine, and I all just walked out of our LHS yesterday with 3 groms (one of each color). We seriously got an hour or so run time on these little groms. That isn't an exaggeration. We have really tight knit, shallow carpet in the basement and we made a few jumps out of the cardboard boxes they came in (just unfolded the top and put some weight in the box to hold it steady)

Anyway, we were all running 50-75% throttle, and we all noticed (obviously after running a brushed motor for around an hour) they got very hot. So now i want to install a fan, but i'm not sure about how to mount them... or what size to try.

The upper portion of the motor heatsink measures 25mm, and counting the two "lower" fins it measures 31.7mm. Will i need a bracket for this thing if i try a 30mm fan?

 

[Tex Koder]

My gf, a close friend of mine, and I all just walked out of our LHS yesterday with 3 groms (one of each color). We seriously got an hour or so run time on these little groms. That isn't an exaggeration. We have really tight knit, shallow carpet in the basement and we made a few jumps out of the cardboard boxes they came in (just unfolded the top and put some weight in the box to hold it steady)

Anyway, we were all running 50-75% throttle, and we all noticed (obviously after running a brushed motor for around an hour) they got very hot. So now i want to install a fan, but i'm not sure about how to mount them... or what size to try.

The upper portion of the motor heatsink measures 25mm, and counting the two "lower" fins it measures 31.7mm. Will i need a bracket for this thing if i try a 30mm fan?

You'll probably want a mount of some kind to secure an alternate fan size to that heatsink..
- Otherwise you're only going to get one corner of the fan bolted down to the heatsink while the remaining corners of the fan just 'float'...

 

[rhinopuncher17]

You'll probably want a mount of some kind to secure an alternate fan size to that heatsink..
- Otherwise you're only going to get one corner of the fan bolted down to the heatsink while the remaining corners of the fan just 'float'...

Any suggestions for the mount? I'm pretty new to the hobby and pretty ignorant as to the options

 

[Tex Koder]

Any suggestions for the mount? I'm pretty new to the hobby and pretty ignorant as to the options

The Grom is Brand spanking new..
I'm not sure if anything is even made/available yet...

You're probably going to need something custom made for that rig.

Take some photos of the heatsink with a ruler next to it -for measurement reference and I'll see if I can come up with something..

 

[rhinopuncher17]

These are my cheap analog imperial calipers, but here are the measurements.

I believe the motor is a 380 size? If that helps. I imagine many more people will have the same question. Appreciate any help in advance

 

[Cirasa]

.

 

[Just a hobby]

This will fit. And 8.4 volt

 

[rhinopuncher17]

This will fit. And 8.4 voltView attachment 331556

Part of the question is mounting, do the screws just self-tap into the fins?

 

[Jluther@becoinc]

Part of the question is mounting, do the screws just self-tap into the fins?

Yes. Squeeze them together if you need to with needle nose pliers

 

[Tex Koder]

Part of the question is mounting, do the screws just self-tap into the fins?

No.
I'll design in a expansion-fitted slots so it will tighten onto the heatsink without gouging into the fins.
Should provide a solid mounting platform for you to install bigger fan..

 

[rhinopuncher17]

No.
I'll design in a expansion-fitted slots so it will tighten onto the heatsink without gouging into the fins.
Should provide a solid mounting platform for you to install bigger fan..

Oh seriously? That'd be awesome. Do you need measurements for the fins?

 

[Tex Koder]

Oh seriously? That'd be awesome. Do you need measurements for the fins?

I'm eyeballing from your earlier photos..

Looks to be a little less than an 1/8" gap between the outer fins..

 

[eXo]

Remember that you still need to be able to push that lever over the motor cooler in order to be able to remove the body. I think adding a fan won’t work height-wise.

 

[rhinopuncher17]

Remember that you still need to be able to push that lever over the motor cooler in order to be able to remove the body. I think adding a fan won’t work height-wise.

I thought about that and seeing the clearance available, i would rather modify the latch if needed than continue to run the motor as hot as it gets.

The latch isnt build to a very tight tolerance anyway, and doesn't need to be pushed all the way in to release the clip either.

The end of that latch is also shaped with a corner moulded in, so that would work to my advantage as well

It is a good thought though, im just fairly sure it will be fine, or would only require minor mods

 

[Tex Koder]

I thought about that and seeing the clearance available, i would rather modify the latch if needed than continue to run the motor as hot as it gets.

The latch isnt build to a very tight tolerance anyway, and doesn't need to be pushed all the way in to release the clip either.

The end of that latch is also shaped with a corner moulded in, so that would work to my advantage as well

It is a good thought though, im just fairly sure it will be fine, or would only require minor mods

I was a tad worried about the whatever custom fan mount I designed it would pose a possible hindrance to that body clip..
Glad to hear you're willing to do some modding if it comes down to it.

Or to at least remove that plastic tab/flap off the spring wire.. (IF it's removable?)
That would surely clear any problems that may arise with the custom fan mount.

 

[Tex Koder]

@rhinopuncher17
Can I trouble you to measure or at least test to see if a M3 screw can fit in between the fins ,area marked below..

 

[Hammer Down]

@rhinopuncher17
Can I trouble you to measure or at least test to see if a M3 screw can fit in between the fins ,area marked below..

View attachment 331999

It’s about 2.6-2.7mm and yes an M3 will screw in there.

 

[Tex Koder]

It’s about 2.6-2.7mm and yes an M3 will screw in there.

View attachment 332001

Thank you sir ,for checking & verification.

 

[Hammer Down]

Thank you sir ,for checking & verification.

No prob Tex!

 

[slick2500]

Just tossing this out there but the motor at normal operating temp will get hot enough to burn you. If you can get 5 Mississippi's before you have to take your finger off for the average person that is about 145*F, most say not to exceed 170*F on any electric motor anything above 200* will likely cause permanent damage to the motor. Buy a temp gun for more accurate readings.