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Old 01-24-2009, 11:25 PM   #1
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Default novak 8.5 brushless motor question

I have a Novak XBR esc & 8.5 motor combo. I purchased a sintered rotor and endbell for it and when i installed it, i reset the esc and ran it. it is noticably less rpm, like about half the rpm. so i put the original bonded rotor back in it and it runs perfectly. I was told by Steve Weiss that it would work. does anyone know why its doing this. I hope that i did not waste my money. This is the esc-motor im running
http://www.teamnovak.com/products/esc/xbr/index.html
http://www.teamnovak.com/products/br...ors/index.html
any info is greatly appreciated!
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Old 01-25-2009, 12:07 AM   #2
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Did you try gearing up? Half the RPM sounds extreme. Its going to have a lot more torque. Try gearing up a few more teeth till ya hit around 130 degrees and see what happens.? If it runs good with the stock rotor then the can id fine, be sure its shimmed right which would be one shim on the pinion side. If its not coming around after that then there's some thing wrong with the rotor.

Does it have more snap when you spin it.
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Old 01-25-2009, 12:28 AM   #3
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What he said.^^^^

That motors' torque will blow you away compared to the bonded rotor.
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Old 01-25-2009, 09:05 AM   #4
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i understand what your saying but it has less rpm with no pinion. just running in my hand
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Old 01-25-2009, 12:09 PM   #5
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Quote:
Originally Posted by mike williams View Post
i understand what your saying but it has less rpm with no pinion. just running in my hand
Sounds like you altered the timing when you put the motor back together. Additionally, the sintered rotor runs at lower rpms with killer torque. Gear more aggressively and have at it. Dont let "free feel" in your hand be your judge...it can be terribly misleading.
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Old 01-25-2009, 12:43 PM   #6
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A word of caution, we advise that you not run BL motors without a load:

Never Free Rev a Brushless motor

If you need advice for Novak products, you can email [email protected]
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Old 01-25-2009, 12:59 PM   #7
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Hi Mike,

You will definately have to gear up with the sintered rotor to get the same top end performance that you got with your bonded rotor.

But just like the other people noted, the sintered rotor generates so much more torque that gearing up will not be a problem.

You WILL get better over-all performance out of your sintered rotor 8.5 than with the bonded rotor.

Usually when switching from the bonded rotor to the sintered rotor, most people gear up 2-3 teeth on the pinon (or more, but I would like my recommendations to be conservative).

With the sintered rotor you're going to get better torque, better brakes, better resistance to heat... meaning that as the system runs it won't be effected by heat as much as the bonded rotor will.

Eventually running the bonded rotor through heat cycle after heat cycle will result in it loosing most of it's magnetism, thus reducing torque, and efficiency...but producing more heat and as a by product of having less "magnetic resistance" more RPM. Overall power will be significantly less than that of sintered rotor.

You're on the right track with the sintered rotor, you just need to gear up!
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Old 01-25-2009, 01:44 PM   #8
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Quote:
Originally Posted by Steve Weiss View Post
Hi Mike,

You will definately have to gear up with the sintered rotor to get the same top end performance that you got with your bonded rotor.

But just like the other people noted, the sintered rotor generates so much more torque that gearing up will not be a problem.

You WILL get better over-all performance out of your sintered rotor 8.5 than with the bonded rotor.

Usually when switching from the bonded rotor to the sintered rotor, most people gear up 2-3 teeth on the pinon (or more, but I would like my recommendations to be conservative).

With the sintered rotor you're going to get better torque, better brakes, better resistance to heat... meaning that as the system runs it won't be effected by heat as much as the bonded rotor will.

Eventually running the bonded rotor through heat cycle after heat cycle will result in it loosing most of it's magnetism, thus reducing torque, and efficiency...but producing more heat and as a by product of having less "magnetic resistance" more RPM. Overall power will be significantly less than that of sintered rotor.

You're on the right track with the sintered rotor, you just need to gear up!

Steve Weiss, I did not mean to drop your name on here, You seem to have a good rep. and i just wanted every one to know that this was the part i needed. Sorry, please don't think I was blaming you.

I understand what everyone is saying and my buddy has the Havoc w/ the 8.5 and I guess it already comes with the sintered rotor. So im gonna gear my to what his is. My motor with the old rotor only got to 85*F at the most. So im pretty safe.

As to what one person said about free-revving: I only gave it a quick throttle, so Im not just free-revving for a long time. Im gonna run it soon and i will post here if it gives me any problems.

THANKS FOR THE INFO TO EVERYONE!!
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Old 01-25-2009, 05:27 PM   #9
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No worries Mike,

I didn't think you were doing anything out of line... I just wanted to clarify anything I may have told you.

Good luck and I'm sure you'll enjoy your system!
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