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Old 12-11-2006, 05:36 PM   #1
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Default Brushless Offroad Systems Advice

Hey Guys,

As from next year im moving to Modified Offroad Truck in 1/10 Electric.

I am going to use Brushless systems and speedies but all i hear is not to use Brushless because they are unrealiable,burn out and they THERMAL!



Can someone give me advice? like why they thermal? do they still thermal? what is a good speedy and brushless motor that does NOT THERMAL. I really would like to run Brushless in Mod Truck but it seems im better off running brushed modified motors. Ive herd GM RACING make the best, expensive but reliable as they have been doing Brushless in Airoplanes for years.

Thanks, Any help appreciated.
JK
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Old 12-11-2006, 05:44 PM   #2
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Ooh you're opening up a can of worms here! You're going to get all kinds of responses.

Here's mine.

I ran Novak GTB for 1 year (5.5 in 2WD bugg). It was fine. Ran cool, never thermalled onece. Then I switched to 4WD mod and am running LRP with the 3-star. Again have never had a problem, never thermalled or cut out once. It's faster (or as fast) as anyone out there.

You'll probably want the 3-star (LRP) or 4.5 (Novak) for mod truck. I say go for it. Your runs will be more consistent because the motor doesn't vary in performance over a race as much as in brushed.

Just dial in heaps of drag braking if you can't get used to no motor braking like in brushed!
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Old 12-11-2006, 05:59 PM   #3
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The 4.5 was originally the touring car motor for Novak. It might be a little much as it's kinda like a 7-8 turn feel. For 2wd truck, the 5.5, or the 6.5 might be a little better.

I ran my GTB and 5.5 in my XXX4 and loved it. Never had a thermal issue. I am going to be getting the LRP Sphere Competition so I don't have to keep adjusting profiles if I do decide to go between brushed and brushless.

One thing to keep in mind if you will be racing, the system must be a sensor based motor.
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Old 12-11-2006, 06:54 PM   #4
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Thanks guys,

I was thinking going Novak or Graupner.
So why do you thermal? what causes it because everyone with a brushless at my club keeps thermalling and shutting down. Obviously running to high of a voltage cells and maybe to tall of a gearing i guess.

So i dial in drag brake so when im off the power it has brake like brushed motors? i hear the brushless sytems are very free rolling.

JK
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Old 12-11-2006, 08:55 PM   #5
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Brushless truck... one word comes to mind. Fun.

Thermalling, i would expect from the 4 wheelers and maybe if you guys run SUPER high traction surfaces or very long striaghts where you gear to the moon.

I was running a 13 overall drive ratio with Nosram (lrp) 6.5 turn in a half MF1/half RTR XXXT. That's the recommended gearing for this motor in offroad for a short track. If im running last heat of the day, i'll stay out on the track for another 10 minutes after the race with GP3900s... the motor may just get warm enough to be able to feel the heat... the speedy will still be at ambient temp (i dont run a fan on the nosram/lrp comp speedy either).

BTW even at 13:1 overall ratio, wasnt getting top speed down the straight... any lower gearing and its too nerve racking with the throttle.

Ask the guys how they're gearing. If its longer than 11 then no one to blame but themselves for thermalling. Or if they running 3.5, 4.5, 5.5 then i'd also suspect they would be struggling to get the gearing right...

Yeah... the motors have almost no drag on them, it's quite strange actually... Even when the truck's not running, you can feel how "loose" they are by turning one of the driving wheels.
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Old 12-11-2006, 09:00 PM   #6
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Double post sorry

Last edited by Bit_Rusty; 12-11-2006 at 09:42 PM.
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Old 12-11-2006, 09:09 PM   #7
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Triple post, sorry.

Mods pls address

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Old 12-11-2006, 10:26 PM   #8
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I ran the 5.5 in my T4, I thought it was great, but I like bug power. I know a lot of people who think its too much.
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Old 12-12-2006, 06:28 AM   #9
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ok, Here is what I have seen. Once you thermal the system a couple of times you are in trouble. It seems to keep thermalling. I believe it has to do with the fact the magnets do not take well to thermalling in the motor and weaken which means it is harder and harder for the motor to work correctly. More heat for less speed. I have had the Novak about 1 year and only thermaled 1 time. (After 20 mins) It was my fault and I thought I might be geared high.

Get the Novak. In a stadium truck unless you are national level or have a huge track I would bet something around the 7.5 is best. I go between the 7.5 and 8.5(5800). You will not thermal. If you want more go with a 6.5 but go ahead and buy a sintered rotor. That will drop the motor temp.

FYI - I run a 7.5 in my truck for 20 mins in race like practice with no fan and do not thermal.
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