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Old 02-25-2009, 11:00 AM   #1
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Default novak 17.5 thermal problems

im running it in a xxx-t mf2

im running a 78 spur.... and i went all the way from 28 thru 34 pin gear

wont run for more than 4 min.....

SOMEONE HELP
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Old 02-25-2009, 11:23 AM   #2
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Most fast 17.5 truck guys are running in the 6.00-6.5 FDR (spur divided by pinion times gearbox ratio = FDR)...if it's overheating at that gear, you probably have either a bad motor, bad ESC or something binding up in the truck (not necessarily in that order).

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Originally Posted by rcwiretek View Post
im running it in a xxx-t mf2

im running a 78 spur.... and i went all the way from 28 thru 34 pin gear

wont run for more than 4 min.....

SOMEONE HELP
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Old 02-25-2009, 12:15 PM   #3
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Agree, I'm running the same motor in a truck with an FDR of 6 and I've yet to hit 140 after a 5 minute run, usually 125-130.
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Old 02-25-2009, 01:46 PM   #4
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If you'er running the 17.5 SS, you should be able run it much hotter than that. Novak suggestes running at 160-170F. Some times I run it even hotter than that, and have not thermaled yet.

Send it to Novak and get it replaced.
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Old 02-25-2009, 02:12 PM   #5
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On my B4, I'm running 78T spur and 29 T pinion. It doesn't even get close to warm and it's slow as hell. Here is the formula for FDR=Spur T / Pionion T * Internal Ratio (B4=2.6)

Based on this, I need to run around 34T Pinion.

I think, you may have a problem with your electronics. Check the wires. Is the sensor wire loose?
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Old 02-25-2009, 03:14 PM   #6
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Quote:
Originally Posted by javacrazy View Post
On my B4, I'm running 78T spur and 29 T pinion. It doesn't even get close to warm and it's slow as hell. Here is the formula for FDR=Spur T / Pionion T * Internal Ratio (B4=2.6)

Based on this, I need to run around 34T Pinion.

I think, you may have a problem with your electronics. Check the wires. Is the sensor wire loose?
No, you just need to gear it right. They need around a 5.0-5.25:1 in a buggy. When you gear them right, they're anything but slow.

http://www.speedtechrc.com/store/ebp...id=322&id=7716

65-67 spur and high 20's pinion with the motor in the front of the plate, not jammed against the guard.
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Old 02-25-2009, 03:17 PM   #7
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Quote:
Originally Posted by Foxxrocket View Post
If you'er running the 17.5 SS, you should be able run it much hotter than that. Novak suggestes running at 160-170F. Some times I run it even hotter than that, and have not thermaled yet.

Send it to Novak and get it replaced.
That's the hottest they recommend, not the target. Some run hotter, some run cooler...but most aren't at 160+. Charlie always recommended the "6 second rule": If you can keep your finger on it for 6 seconds, it's not too hot.

120-150 is pretty reasonable from what I've seen.
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Old 02-25-2009, 06:13 PM   #8
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I find the higher you gear the 17.5 the better it works.I currently run the 72 spur 34 pinion on my B4 buggy and the motor is crying for more so i'm going to try the 36 pinion .with the 34P the hottest it gets is 110deg after 15 min
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