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brainanator
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03.13.2012, 10:53 PM

:D :D awesome!


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fastbaja5b
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03.14.2012, 01:53 AM

200f is too hot, something's not right there.


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auto2
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03.14.2012, 06:21 AM

im only braking once or twice a lap. just a touch to slow it after the straight and in the middle.i could do a test an do no braking and see if temps go down.
its still overgeared for this track. would like to try a 16 pinion.
   
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Cain
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03.14.2012, 10:57 AM

Quote:
Originally Posted by auto2 View Post
im only braking once or twice a lap. just a touch to slow it after the straight and in the middle.i could do a test an do no braking and see if temps go down.
its still overgeared for this track. would like to try a 16 pinion.
Definitely worth a shot to try the gearing first and see how it goes. Hopefully it works out for you.
   
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killajb
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03.14.2012, 07:27 PM

Quote:
200f is too hot, something's not right there.
My thoughts exactly, something's definitely not right much longer at 200f.. demagnetizing effect would ruin one's day I think..
   
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Overdriven
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03.14.2012, 07:53 PM

Wow, thats a huge difference! You could almost make that triple into a quintuple if it weren't for the fact you couldn't slow down enough for the next turn! I see what you mean about the stocker not being able to turn enough though. Gotta love brushless, always enough power on tap to do whatever you want!


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auto2
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03.14.2012, 08:00 PM

i did make a quintuple plus a few feet and ended up in the next lane. if you play with it in the air you can get it to slow down and just land for the rt turn. i made it once out of 3 and decided to just do a quad lol
   
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  (#68)
auto2
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03.14.2012, 09:16 PM

Quote:
Originally Posted by killajb View Post
My thoughts exactly, something's definitely not right much longer at 200f.. demagnetizing effect would ruin one's day I think..
i changed the current limiter from 200 to 150 just before that run. could that cause the motor to heat up?how?
   
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FG101C
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03.14.2012, 10:14 PM

It's diffing out to the front a lot. From my experience with brushless motors, this is just my experience, brushless motors like a load. Diffing out may be causing the motor to run with less of a load causing slight over revving. I fixed this same sort of issue in my 1/8th Truggy by going to a thicker center diff oil.

In my baja the 2028 was running hot, so I went up two teeth on the pinion and it coooled down some.

Again this is just from my experience, I'm by no means saying that's the problem with your truck or saying I'm an expert at this...end disclaimer.
   
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killajb
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03.15.2012, 12:24 AM

Quote:
i changed the current limiter from 200 to 150 just before that run. could that cause the motor to heat up?how?
Not exactly sure and there could be a few causes to reason.. FG101C may be on the right track regarding the center diff in general.

I've stated elsewhere about the heat generated through the use of a center diff that unloads quite often on my heavy vehicles. Mike countered that the sharp angles of the drive shafts are the reason for excessive heat.

In either case (or perhaps both combined), the motor mount transfers that heat as well. I'm sure that would contribute to overall high motor temps.

Patrick from Castle can chime in on the efficiency curve of the 2028. In my XBE for example, a 1520 runs cooler with the relatively tall stock gearing (~50mph) than a 1717 does. Hard to fathom at first, but then CC released info that the 1717 seems to "brick wall" after certain rpm's in terms of efficiency.

Regardless of the cause, I go for the lowest temps possible and 200f is pushing it. Sometimes a little trial and error is in order to find where things seem most comfortable.

Last edited by killajb; 03.15.2012 at 12:26 AM. Reason: add'l info
   
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fastbaja5b
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03.15.2012, 12:48 AM

That's also why you should never test a brushless motor on your bench with no load!


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auto2
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03.15.2012, 06:54 AM

Quote:
Originally Posted by FG101C View Post
It's diffing out to the front a lot. From my experience with brushless motors, this is just my experience, brushless motors like a load. Diffing out may be causing the motor to run with less of a load causing slight over revving. I fixed this same sort of issue in my 1/8th Truggy by going to a thicker center diff oil.

In my baja the 2028 was running hot, so I went up two teeth on the pinion and it coooled down some.

Again this is just from my experience, I'm by no means saying that's the problem with your truck or saying I'm an expert at this...end disclaimer.

i have 30000 dif oil in the center and its still diffing out lol
well this is interesting cause i though it would of run hotter on the street using a lot of brakes and basically dragracing over and over but it ran hotter on a dusty track with no real traction with a 17 pinion where i had an 18 on the street. i probablly didnt drive it for 12 minutes on the street though cause bashing gets boring to me real fast. plus it was 45-50 degrees during the street test and the track test was 70 degrees f

Last edited by auto2; 03.15.2012 at 06:56 AM.
   
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freddy
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03.15.2012, 07:28 AM

The motor looks tiny in that vehicle, guess if you have it geared wrong it will quickly damage the motor.
   
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auto2
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03.15.2012, 07:37 AM

i never thought 30,000 would diff out like that.:-) well guys what do you-all suggest? 50,000 and gear it for 55MPH ? i used brians speed calculator and without ballooning tires the 17 i have in it is geared for like 46 mph + or- and i doubt im going that fast on the straight? mike is sending me a 16 t to try and if that doesnt help its back up to 18T oh and BTW the 18 pinion is SICK! FAST. but full throttle from a dead stop was worse with the 18. from a slight roll it lifted the ft tires for a sec.

Last edited by auto2; 03.15.2012 at 07:46 AM.
   
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auto2
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03.15.2012, 07:49 AM

"I've stated elsewhere about the heat generated through the use of a center diff that unloads quite often on my heavy vehicles. Mike countered that the sharp angles of the drive shafts are the reason for excessive heat. "

yes center diff front cup is 180 degrees. some of the gas guys that run for hours have actually got the dog bone blue from the heat. the rear cup was 150.
   
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