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  1. #1
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    39087-1 stock E-Maxx

    I took this truck to a park yesterday. Drove it on large grassy fields. I pretty much was going full speed back and forth over and over. the truck reached 180 degrees before the dual 3S 5000 mAh Lipo's ran out of. Before, this didn't happen in my backyard, but the difference I realize now is that I was doing more driving and less turning around to go the other way while out at the park.

    What cooling options do I have? I know they have fans that mount to the motor. I've also seen fins that mount to motors. I have also seen people cut out the window in their body to act as an intake. What have you guys seen as the most effective way for keeping the motor cool for those "near" non-stop speed runs?

    I just realized, I didn't title this thread right. I can't find a way to edit the title of the thread.

  2. #2
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    It will be hard to keep it cool running 6s, maybe you can try with a lower pinion, cut some holes on the front of the body and let it cool between runs.

  3. #3
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Mine use to run at 160 degrees with the factory 68/17 gearing. Now, I hang around between 113 and 123 degrees with factory gearing. What I did first was, I dumped Castles' plastic fan rig, and put on a aluminum fined Kershaw heat sink with the two fan setup. Then, I started making my bodies with better air flow.

    For example: An air scope in the front.



    And, air flow exits in the back.

    Last edited by ReglarGuy; 06-10-2015 at 04:33 PM.
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  4. #4
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    Quote Originally Posted by ReglarGuy View Post
    Mine use to run at 160 degrees with the factory 68/17 gearing. Now, I hang around between 113 and 123 degrees with factory gearing. What I did first was, I dumped Castles' plastic fan rig, and put on a aluminum fined Kershaw heat sink with the two fan setup. Then I started making my bodies with better air flow.
    That's really cool.

    Okay, first off, how did you run at 160 degrees at stock when my truck is 100% stock and going above 180 and I have to turn it off before I go any higher. Give me your typical driving scenario where you would be at 160. Were you running 6S? While you were driving, did you go to a big grassy field and drive mostly full speed? The reason I ask is because I just want to make sure everything is working properly on my truck, I just want to figure out the explanation as to why my temp is 20 degrees higher than yours.

    Also, I just checked out the Kershaw Designs website and I can't figure out how to navigate to the heat sink. Can you point me in the right direction?

  5. #5
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    Well, I could never figure out how to navigate to it on their website, BUT, I did a google search and found this:http://www.kershawdesigns.com/MotorCare.htm

    Is it the Integy 700/820 Twin Motor Heat Sink Fan? (oh, and it says it's for "brushed motors", does this matter?)

    Also, you said you dumped Castles plastic fan rig but why not have both the motor heat sink fan as well as Castle's fan that goes to the ESC?

  6. #6
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    As soon as I get a chance I'll answer all your questions.
    The ReglarGuy is kid tested and father approved.

  7. #7
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Give me your typical driving scenario where you would be at 160. Were you running 6S?
    When I first got my truck, I ran it on grass in the back yard for my first season. It really use to get hot, but being I was just getting back into RC I didn't take any temp readings. Back then, I used both 7cell Nims and 6s Lipo batteries. Now however, I strictly run 6s, and only run on dirt tracks climbing 15 to 20 foot dirt mounds with some speed runs on the flat parts of our track. I would think driving on grass would be harder on your truck, and not as fun as driving on dirt. If you can maybe you could do what we do. My buddies and I find constuction sites to play on during the weekends. It's a lot more fun than grass.

    I run mostly stock with the exception of using steel drive shafts, steel axles, and aluminum bumpers. One of the thing you can do to make sure you trucks' mechanics are right is to loosen the motor away from your spur gear and roll your truck around by hand. If you are having any binding issues (slight or otherwise) you can eaily feel it by doing this.

    Well, I could never figure out how to navigate to it on their website.
    To see the Kershaw dual fan aluminum fined heat sink I'm telling you about...go to the Web Site, at the top of the page click PRODUCTS. Then at the bottom of the page click on BRUSHLESS MOTORS. On the top of the next page you will see a blue dual fan aluminum heat sink. That's the one I have, and it really works well. It is well worth the 30 bucks.

    Also, you said you dumped Castles plastic fan rig but why not have both the motor heat sink fan as well as Castle's fan that goes to the ESC?
    That's what I have. I have the Kershaw dual fan aluminum heat sink on my motor, and I have the fan set up that normally comes with a MM2 ESC on my MM2 ESC. Castle makes a plastic fan kit for its' 1515 2200kv motor that comes with our trucks MM2 system. I think the Kershaw dual fan aluminum heat sink setup is much better for our motors than the single fan, plastic, no heat sink Castle setup.
    Last edited by ReglarGuy; 06-11-2015 at 08:26 AM.
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  8. #8
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    We are talking about (http://kershawdesigns.com/Products.htm) aren't we? That's the page that displays when you click products. There is no "Brushless Motors" link at the bottom. They do have a "Brushless Motors and Speed Controllers" option. If I click that, it gives me four more different options. None of those options lead to a heatsink/fan combo. When you described how to navigate to it above, did you actually do it? I ask because I wonder if they changed their website recently and maybe they no longer offer that product.

  9. #9
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    Okay, I think I got it now.

    First click on "products"
    Then "brushless motors and speed controllers"
    Then "brushless motors"
    Then "kershaw designs Gen 5 brushless motors"
    And then you see it at the top listed at $29.99. It's called the "Yeah Racing Twin Motor Fan/Heat Sink" and the description says "For all 40 and 42 mm diameter motors." It doesn't say it's a Kershaw, I wonder if they are calling them "Yeah" lol.

  10. #10
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    I made a modification to my body.



    Notice how I made the cut and "bend" to act as a vent that directs the air to a specific spot.

    After doing that, I went out to perform a test. I drove around full speed on 6S out in that large grassy field. Somewhere around 10 minutes into it (maybe more) I was somewhere around 160 degrees, so obviously I would like to do a little more to cool it down. UNFORTUNATELY, I made a slight lapse in judgement on distance between me and a tree and I "baaaarely" bumped it with my left front tire and the lower ball joint popped out. So then I had to remove the tire, remove the ball joint nut, unscrew the ball joint from the arm, and put it through the carrier and then reassemble everything. By the time I was done the truck had already cooled down to like 112 degrees. I had a little bit of juice in my 6S and went back out but it never got past 140. When it ran out, I through on the 3300 NiMH (that comes with the truck) in the hopes that I could continue to increase the temp and it never got past 145 after draining the entire battery.

    So, my little body modification may have added some cooling power, but I don't think it was enough.

  11. #11
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    Yea, driving on dirt is definitely more fun. I just don't have anywhere to go during the weekdays. There is a construction site nearby that I could go to on the weekends, and I did take it out there "once" last weekend, but that place is definitely no place to take a 6S. The terrain is way way too rugged.

    Also, the other problem with grass is all the grass that gets clogged inside the truck, ESPECIALLY after I made the cut in my windshield. I noticed that the fan on my esc wasn't blowing at the end of my run today so now I have to figure out how to clean it out...

  12. #12
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    Quote Originally Posted by ReglarGuy View Post
    That's what I have. I have the Kershaw dual fan aluminum heat sink on my motor, and I have the fan set up that normally comes with a MM2 ESC on my MM2 ESC. Castle makes a plastic fan kit for its' 1515 2200kv motor that comes with our trucks MM2 system. I think the Kershaw dual fan aluminum heat sink setup is much better for our motors than the single fan, plastic, no heat sink Castle setup.
    Yea, my stock 39087-1 truck didn't come with a fan on the motor, it only came with a fan for the ESC. Just so I understand correctly, the MM2 you refer to is the same thing as my MXL-6S, right?

    So did you buy a 3908, or did you convert something else to brushless? It's starting to sound like you converted something to brushless, and you bought a Castle motor and ESC combo and it also sounds like your Castle motor came with the Castle motor fan. Is my assumption correct?

  13. #13
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    Gosh, if I put fans on my motor and I end up with three fans inside my truck, how do I prevent grass from getting in?

    I thought about putting chicken wire in my window, lol, but I don't think it will be very effective, lol. Would look cool though.

    I wonder how well the fans perform and keep the motor cool "without" the scoop on the hood. I guess I'll order the dual fan setup and do another test with the windshield blocked.

    By the way, how come they have the telemetry sensors monitoring the motor temps but not the ESC temps. Will the ESC temp NEVER reach the temp of the motor or something? I ask because it got me worried when I saw that my ESC fan was completely clogged.

  14. #14
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Just so I understand correctly, the MM2 you refer to is the same thing as my MXL-6S, right?
    Yep.

    So did you buy a 3908, or did you convert something else to brushless? It's starting to sound like you converted something to brushless, and you bought a Castle motor and ESC combo and it also sounds like your Castle motor came with the Castle motor fan. Is my assumption correct?
    Nope. My truck has always been brushless, but when I got it, it came with a MM1. About 2 years ago, my MM1 blew, so I upgraded my ESC to the MM2.

    Gosh, if I put fans on my motor and I end up with three fans inside my truck, how do I prevent grass from getting in?
    I'd go with a hood scoop rather than opening up my windshield, and wait a couple of days after you cut the grass before you run your truck on it.

    By the way, how come they have the telemetry sensors monitoring the motor temps but not the ESC temps. Will the ESC temp NEVER reach the temp of the motor or something? I ask because it got me worried when I saw that my ESC fan was completely clogged.
    I've never had my ESC get hot, but this is what I did to make it easier to keep cleaned and lubed.



    The ReglarGuy is kid tested and father approved.

  15. #15
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    In the pictures above, did you take the fan out from inside that silly box or something?

    Hey, I'm looking for that hood scoop you have. I see that it says Proline on it, but I can't find it anywhere on their website. I did find these guys though: http://www.oocrcracing.com/ Has anyone used any of these before?

  16. #16
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    Nevermind, I learned your scoop was a custom job. I found this: https://traxxas.com/forums/showthrea...ighlight=SCOOP

  17. #17
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Nevermind, I learned your scoop was a custom job.
    That's it, you got it.

    In the pictures above, did you take the fan out from inside that silly box or something?
    Nope, just get a pair of nippers, and cut the plastic cover out.
    The ReglarGuy is kid tested and father approved.

  18. #18
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Also, if you want to make an air scoop all you have to do is get a shop-vac attachment from like Lowes or Home DeePot, and use a belt sander to shape it the way you want. Each truck body is different, so how a person makes their air scoop will not be the same as others.
    The ReglarGuy is kid tested and father approved.

  19. #19
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    $29.99, plus $8.99 for shipping, geez. Hope it's worth it.

  20. #20
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    This looks like it could be made into a nice scoop.
    http://www.amazon.com/WORKSHOP-Wet-D...hop+vac+nozzle

    $12 with free shipping
    Proud member of the red card club.

  21. #21
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    Yep, that's what they look like before I hack-em up.
    The ReglarGuy is kid tested and father approved.

  22. #22
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    The guy from Kershaw Designs sent me a message saying all they had was the black.... I was hoping for blue, but oh well.

  23. #23
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    I received the Kershaw Designs dual fan/heat sink today. I put the heat sink on, but the instructions are far from clear on the fan install. First off, they show "two options", one with the two fans screw flush against the heat sink and the second option is with the spacers installed in between the fans and the heat sink. There is also zero instruction on fan orientation. The fans themselves have no markings to indicate direction of air flow and the instructions don't indicate which direction air should flow. I've read different opinions in other threads. Some say to point flow towards motor to blow cool air on motor and some say to point flow away from motor to blow hot air away from motor. So which is it?

  24. #24
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    You want to pull the hot air off the motor. The amount of air that fan pushes wouldn't be efficient enough to cool it if it was blowing on the motor. So the key would be to pull that air away from the motor.....much like a heat sink does.

  25. #25
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    How about the spacers? Install with or without them?

  26. #26
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    I'm sorry but I'm not familiar with the particular setup your using. I did know the answer to the first question as far as which direction for air flow. The spacers I'm unaware of....

  27. #27
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    I have found better cooling attributes from a fan that blows directly onto the motor, mainly from the rear and sides. I never found great cooling attributes from a heat sink where the fan pulled hot air off the heatsick, which is transfering heat from the motor can heat sinks. Keep in mind you can replace the fan in the Castle ESC and Motor Cooler Fan with upgraded versions that spin faster, and have a higher voltage ratings which means the fans can operate faster without getting hot themselves at higher voltages, and this is especially true if you are running a BEC. If you set your BEC for 6.0 volts, remember castle's fans are rated at 5.0v, anything above will make them spin faster, but the fans will generate heat themselves, so you want one that operates at a higher voltage. I changed mine out, and found a big difference.

  28. #28
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    Great. You proved my point to some degree, air being blow on the motor is a more effective cooling method. In your case, you don't even need a fan. Keep it up. Great work.
    Quote Originally Posted by jmwman View Post
    I made a modification to my body.



    Notice how I made the cut and "bend" to act as a vent that directs the air to a specific spot.

    After doing that, I went out to perform a test. I drove around full speed on 6S out in that large grassy field. Somewhere around 10 minutes into it (maybe more) I was somewhere around 160 degrees, so obviously I would like to do a little more to cool it down. UNFORTUNATELY, I made a slight lapse in judgement on distance between me and a tree and I "baaaarely" bumped it with my left front tire and the lower ball joint popped out. So then I had to remove the tire, remove the ball joint nut, unscrew the ball joint from the arm, and put it through the carrier and then reassemble everything. By the time I was done the truck had already cooled down to like 112 degrees. I had a little bit of juice in my 6S and went back out but it never got past 140. When it ran out, I through on the 3300 NiMH (that comes with the truck) in the hopes that I could continue to increase the temp and it never got past 145 after draining the entire battery.

    So, my little body modification may have added some cooling power, but I don't think it was enough.

  29. #29
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    Quote Originally Posted by BuGgYbAsHeR.28 View Post
    I'm sorry but I'm not familiar with the particular setup your using. I did know the answer to the first question as far as which direction for air flow. The spacers I'm unaware of....
    Here is a link to some info on the fan/heat sink combo. If you scroll down to the bottom, you'll see a black and white instruction sheet with two installation options.

    http://www.yeahracing.com/catalog/ya...er-p-3052.html

    RegularGuy, how did you install yours?

  30. #30
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    Quote Originally Posted by SHIFTT IX MR View Post
    Great. You proved my point to some degree, air being blow on the motor is a more effective cooling method. In your case, you don't even need a fan. Keep it up. Great work.
    It wasn't as effective as I was hoping, which is surprising to me actually. I mean, imagine yourself going 50 mph in the car and sticking your hand out the window. It just seems like I would be getting a ton of air. Who knows, maybe I just need to adjust the "fins" in my windshield vent a little, maybe tape the corners or something. Anyways, the result of the windshield vent cutout basically enabled me to drain the battery without overheating. Before, I would eventually hit 180 degrees with juice on the battery still, but with the windshield cutout I was able to drain the battery. The temp was 185 however. It took 16 minutes to drain the Onyx 3S 5000 mAh 25C. Anyways, something for you guys to keep in mind, the tests were done in a large grassy field where they say that driving on grass is the harshest of environments. Also, since I'm testing, the goal is to push the motor and temps to the limit, so basically the goal is to keep my average speed as high as possible during the length of time it takes to drain the battery. You can't do that at a track.

    Well, I'll try taping the corners of my windshield vent cutouts, maybe too much air is escaping or something. Maybe it's not funneling very well. It just seems like it should be getting a ton of fresh air.

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