Mojave Motor fan recommendations for HW 4985

Currently reading:
Mojave Motor fan recommendations for HW 4985

Dan B.

Area man
Premium Member
Messages
58
Reaction score
45
Location
Southern Vermont
Arrma RC's
  1. Mojave EXB
Howdy. I was hoping to get a recommendation for a single or double cooling fan setup with heat sink for my HW 4985 motor. I’ve seen that the Max 6 combo with this motor is one of the most popular for these trucks, but I’m so far unable to find a 49mm (+/-) heat sink with fan mounts on that god dawged interweb. I hit 215° today on the end plate of the motor, so it mos def needs some help cooling itself and I won’t be repeating any more extended bash sessions until I gear down. It has a 21t pinion in it, and I’m planning to step down to a 19t as soon as it arrives. Funny, most say they don’t really have any heat issues running this combo with 21t, but mine sure does. I am running gens-ace 100c batteries, so maybe that’s contributing. IDK. The batteries were very warm but not hot, and the ESC temp was 115° which seems fine. But any recommendations and links to where this motor cooling setup might be found would be greatly appreciated.
That said…Good God what a freaking beast this thing is! This was probably my 6th or 7th outing with it and I’m still just blown away. Coming from 1/10 3s SCT’s this is a HUGE jump! I wish I would have bought one of these things a long time ago. I’ve probably got upwards of $900.00 in one of my 2wd Slash trucks and now that just sounds outright stupid. (But that particular truck is actually pretty groovy, and it’s still a lot of fun.). Any-who, please let me know what y’all are doing to cool these motors. Thanks!
 
Last edited:

Sargent_Horse

Well-Known Member
ArrmaForum Fan
Build Thread Contributor
Messages
1,231
Reaction score
1,166
Arrma RC's
  1. Infraction
  2. Kraton 6s
Howdy. I was hoping to get a recommendation for a single or double cooling fan setup with heat sink for my HW 4985 motor. I’ve seen that the Max 6 combo with this motor is one of the most popular for these trucks, but I’m so far unable to find a 49mm (+/-) heat sink with fan mounts on that god dawged interweb. I hit 215° today on the end plate of the motor, so it mos def needs some help cooling itself and I won’t be repeating any more extended bash sessions until I gear down. It has a 21t pinion in it, and I’m planning to step down to a 19t as soon as it arrives. Funny, most say they don’t really have any heat issues running this combo with 21t, but mine sure does. I am running gens-ace-r-spam 100c batteries, so maybe that’s contributing. IDK. The batteries were very warm but not hot, and the ESC temp was 115° which seems fine. But any recommendations and links to where this motor cooling setup might be found would be greatly appreciated.
That said…Good God what a freaking beast this thing is! This was probably my 6th or 7th outing with it and I’m still just blown away. Coming from 1/10 3s SCT’s this is a HUGE jump! I wish I would have bought one of these things a long time ago. I’ve probably got upwards of $900.00 in one of my 2wd Slash trucks and now that just sounds outright stupid. (But that particular truck is actually pretty groovy, and it’s still a lot of fun.). Any-who, please let me know what y’all are doing to cool these motors. Thanks!

Pretty sure the Alza racing motor fan mount (which can be single or dual 40mm fans) works in that can. Perhaps send Alza an email asking. Powerhobby has a 1/5th scale motor heatsink that would likely work.
 

Dan B.

Area man
Premium Member
Messages
58
Reaction score
45
Location
Southern Vermont
Arrma RC's
  1. Mojave EXB
Pretty sure the Alza racing motor fan mount (which can be single or dual 40mm fans) works in that can. Perhaps send Alza an email asking. Powerhobby has a 1/5th scale motor heatsink that would likely work.
Alta only has the ones for the BLX models with the Spektrum 40mm can. Same with Powerhobby. The HobbyWing is A 49mm can. I could go a few mm under and stretch it a bit, but no way a 40mm heat sink would conform to a 49mm can.
 

jkflow

TB RC Bashers
Premium Member
ArrmaForum Fan
Excellence Award
Build Thread Contributor
Messages
4,767
Reaction score
5,693
Location
Tampa, FL 🇺🇸
Arrma RC's
  1. Infraction
  2. Kraton 6s
  3. Talion
This works as well,
Motor mount
https://www.ebay.com/itm/393222917261

At 212F your motor is already permanently damaged. The epoxy holding the kevlar on the mpotor breaks down at 190F. Plan on getting a new motor soon. Keep that in mind.

I run an 18T and have heat issues, keep in mind that different people bash differently. If you do jumps and hops with breaks in between, you won't have heat issues. If you are 'ba**s to the walls', yes you will have heat issues.
For bashing, stay away from these big fans. They will break when jumping. I'm using 2ea. 35mmx10mm fans myself and stays within a decent range. They fit side by side on the mount I linked above. Won't break the bank, works and holds up to bashing.

Fans:
https://www.ebay.com/itm/284417058561?hash=item423893e701:g:kyYAAOSwwK5hH0ht
 

Dan B.

Area man
Premium Member
Messages
58
Reaction score
45
Location
Southern Vermont
Arrma RC's
  1. Mojave EXB
I did read a TON of posts here about this, but I’ve yet to find a 49mm heat sink. I’d prefer not to stretch or “persuade” one that’s too small onto the can. To be effective a heat sink has to fit perfectly. I do realize that the ribs/fins on the HW 4985 help to cool it, and that because of those the surface area that a heat sink would contact would essentially be cut in half, but I was still hoping to find one with a dual fan setup.
This works as well,
Motor mount
https://www.ebay.com/itm/393222917261

At 212F your motor is already permanently damaged. The epoxy holding the kevlar on the mpotor breaks down at 190F. Plan on getting a new motor soon. Keep that in mind.

I run an 18T and have heat issues, keep in mind that different people bash differently. If you do jumps and hops with breaks in between, you won't have heat issues. If you are 'ba**s to the walls', yes you will have heat issues.
For bashing, stay away from these big fans. They will break when jumping. I'm using 2ea. 35mmx10mm fans myself and stays within a decent range. They fit side by side on the mount I linked above. Won't break the bank, works and holds up to bashing.

Fans:
https://www.ebay.com/itm/284417058561?hash=item423893e701:g:kyYAAOSwwK5hH0ht
PowerHobby 47-49 dual mount sporting two 32k Rockets. Almost surprised I don't get lift off View attachment 169284

Link was listed above
Thanks guys, I guess this is the route I’ll take, along with gearing down several teeth. Probably going to a 17t pinion and see how it goes. Thanks again.
 

Greengaunja

Ise da by' dat burns da Senton........
Premium Member
ArrmaForum Fan
Build Thread Contributor
Messages
1,132
Reaction score
1,249
Location
Durham Region, Ontario Canuckistan
Arrma RC's
  1. Senton 6s
  2. Senton 3s
I did read a TON of posts here about this, but I’ve yet to find a 49mm heat sink. I’d prefer not to stretch or “persuade” one that’s too small onto the can. To be effective a heat sink has to fit perfectly. I do realize that the ribs/fins on the HW 4985 help to cool it, and that because of those the surface area that a heat sink would contact would essentially be cut in half, but I was still hoping to find one with a dual fan setup.
A guy in my local rc group explained it this way. The can design is the heat sink, as is anything attached to it that can take on heat. The ribs in the can actually "make the cans bigger". The more area being heated, the more heat being taken away from the motor and the more are being cooled. That's why bigger bulkier heatsinks are usually only made for and found on smooth cans.
 

YiKKiT

Active Member
Messages
36
Reaction score
20
I have and can recommend the above mentioned powerhobby clamp mount..

I to spent lots of time tryin to find a fan set up as I was running very hot on even 19t

those mounts are the cleanest setup you can do I believe and they are very affordable..they are very easy to install and easy to adjust!!

im running 2-30mm $15 Amazon(rocket) fans and highest temp I’ve seen on 19t is 130-140 on back side of motor(where fan isn’t directly blowing)

105-110 on motor right where fans are directly blowing..this is also hard constant driving trying to see how hot I could get it!!

also I’m running them at 7.4v..they still do great on 6v!!

I don’t see a need for those big bulky setups..this setup works great and I’ve put hand full of packs through this set up and it holding up great!!

I’d also recommend not dropping to 17t..get ur cooling ironed out and it handles 19-21t gears fine!!

Side not..I put one of those same fans in the max6 esc(literally broke stock fan on first session..in grassy yard lol)

it’s smaller that stock fan but I make it work by putting one screw through one hole and they rest kind of lock in the edges so it doesn’t move around

if you can’t tell I love those fans..even put one in my senton 6s blx esc..they seem tobe durable and move hella air
 
Messages
593
Reaction score
899
Arrma RC's
  1. Kraton 6s
  2. Kraton EXB
  3. Notorious
  4. Talion
  5. Typhon 6s
Ok, now I understand. They attach with a zip tie and not with an aluminum round heat sink. Do they work well? How much did they drop your temps, and what fans are you using? What gearing are you running? Thanks so much!
Before I installed them it was hitting thermal every run on a 20t. Now they are cool to the touch. I use one of the aluminum framed fans mentioned above on another basher and it's more robust and is better suited to this application. I didn't know at the time that these fans are not really the right ones, apparently you need spacings between the blades.
 

slick2500

If it ain't broke, you're doing it wrong.
Community Leader
Premium Member
ArrmaForum Fan
Excellence Award
Build Thread Contributor
Messages
16,812
Solutions
7
Reaction score
19,368
Location
Rapid City, SD
Arrma RC's
  1. Outcast 6s
  2. Senton 3s
  3. Typhon 3s
I did read a TON of posts here about this, but I’ve yet to find a 49mm heat sink. I’d prefer not to stretch or “persuade” one that’s too small onto the can. To be effective a heat sink has to fit perfectly. I do realize that the ribs/fins on the HW 4985 help to cool it, and that because of those the surface area that a heat sink would contact would essentially be cut in half, but I was still hoping to find one with a dual fan setup.


Thanks guys, I guess this is the route I’ll take, along with gearing down several teeth. Probably going to a 17t pinion and see how it goes. Thanks again.
The motor can itself is already a heatsink, that is what the ribs are for and keep in mind that is all that the heatsink will come into contact with. Only use heatsinks on smooth motor cans. Other than making something yourself the Alza or Powerhobby fan mounts are your best bet. And those Rocket fans are really nice as they move a boat load of air, I have a couple of the Trackstar branded ones(same fan just a different name).

Here is my setup/
 

Greengaunja

Ise da by' dat burns da Senton........
Premium Member
ArrmaForum Fan
Build Thread Contributor
Messages
1,132
Reaction score
1,249
Location
Durham Region, Ontario Canuckistan
Arrma RC's
  1. Senton 6s
  2. Senton 3s
Note:
With Rockets, the same size/models seems to come in different RPMs and even re-branded. The one constant similar feature is the aluminum body that makes it stronger and even acts as a heatsink itself. Now honestly, I'm not even sure there is a difference.
I've seen 16k, 21k, 28k, and 32k. This could be sellers not knowing or being fraudulent for all I know. But the same can been seen with the difference in voltages for the DS3235 servos. I got the 32k rpm fans and only hope I'm getting that.
 

Sandracer_NL

Well-Known Member
ArrmaForum Fan
Build Thread Contributor
Messages
1,096
Reaction score
1,484
Location
Netherlands
Arrma RC's
  1. Mojave EXB
Note:
With Rockets, the same size/models seems to come in different RPMs and even re-branded. The one constant similar feature is the aluminum body that makes it stronger and even acts as a heatsink itself. Now honestly, I'm not even sure there is a difference.
I've seen 16k, 21k, 28k, and 32k. This could be sellers not knowing or being fraudulent for all I know. But the same can been seen with the difference in voltages for the DS3235 servos. I got the 32k rpm fans and only hope I'm getting that.
AFIAK the RPM’s depend on the fan size; the smaller the fan size the more rpm’s. Not saying some sellers just mention something, but most state 28k for the 30mm fan (on 8.4v that is).
I recently also got the 35mm fan (21k rpm) for the Max6 and the 50mm fan (10k rpm) for a Hobbywing heatsink. The 25mm should be 32k rpm and 40mm fan 16k.
At least according to specs, your real mileage may vary😂
 

Greengaunja

Ise da by' dat burns da Senton........
Premium Member
ArrmaForum Fan
Build Thread Contributor
Messages
1,132
Reaction score
1,249
Location
Durham Region, Ontario Canuckistan
Arrma RC's
  1. Senton 6s
  2. Senton 3s
How are you powering these, off the receiver or with a battery lead adaptor?
Soon to be powered by a separate 2s battery. I run 5 fans, including esc.
4 fans will run constant on 2s
AFIAK the RPM’s depend on the fan size; the smaller the fan size the more rpm’s. Not saying some sellers just mention something, but most state 28k for the 30mm fan (on 8.4v that is).
I recently also got the 35mm fan (21k rpm) for the Max6 and the 50mm fan (10k rpm) for a Hobbywing heatsink. The 25mm should be 32k rpm and 40mm fan 16k.
At least according to specs, your real mileage may vary😂
Makes sense. I couldn't for the life of me understand the rpm differences in the exact same thing. Guess if I wanted, I can get my money because both sets of fans came from China and I doubt they will want them shipped back. I thought I was getting better for the wait because ONLY the Rockets 30mm from China are listed 32k rpm. Either way, it has been working with the load im putting on the motor and esc.
 
Top