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austinmaxx
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12.27.2007, 01:37 PM

Hummm so traxxas knew all along when they had that novak hv bolted up at the show...thats pretty sad to be deciving like that...I won't buy any motors they come out with for it ...i won't support that kind marketing pretty crappy hey would a 1515/1.5d work for new e-maxx? could you gear it right with 4s lipo?
   
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lincpimp
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12.27.2007, 03:24 PM

Good lord! You guys are really giving Traxxas a hard time. Look, the revo style slipper will only fit one way, just because the hv maxx shaft is too short for this application does not mean traxxas did that intentionally. They could have designed a 32p gear that works the same way as the 48p rustler/stampede gear, but it was not required for the titan motors to work correctly. Plus the novak motor is too small and not powerful enough to give much benefit over the titan setup. If I am going to spend 250 - 300 on a brushless sytem it better be capable of twice the power/speed of what I am replacing. I am sure tha Novak's hv replacement will be up to the task, as will the castle MMM. And both of those should have 5mm shafts, so pinion placement will not be so critical.

Give Traxxas a break, they are the only MFG with a factory truck that can handle high power brushless.
   
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steve050773
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12.27.2007, 04:14 PM

Quote:
Originally Posted by lincpimp View Post
Plus the novak motor is too small and not powerful enough to give much benefit over the titan setup.
That's so far from the truth that its not even funny.
   
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lincpimp
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12.27.2007, 04:58 PM

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Originally Posted by steve050773 View Post
That's so far from the truth that its not even funny.

Ok, seriously, have you calculated the speeds with novak's recommended gearing?

http://www.teamnovak.com/products/in...v_gear_add.htm

Given that info, and the pulished kv ratings of the two hv motors (3100, 4800) here are the calculated speeds of both motors in an old style emaxx in 2nd gear on 12 cells.

6.5 Motor:

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.7222222222222223
Spur Tooth Count: 70
Pinion Tooth Count: 14
Total Voltage: 14.4
Motor KV: 3100
Tire Diameter (inches): 5.75
Spur/Pinion Ratio: 5 : 1
Total Ratio: 24.50855 : 1
Total Motor Speed: 44640 RPM
Vehicle Speed: 31.16 MPH

4.5 Motor:

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.7222222222222223
Spur Tooth Count: 70
Pinion Tooth Count: 14
Total Voltage: 14.4
Motor KV: 4800
Tire Diameter (inches): 5.75
Spur/Pinion Ratio: 5 : 1
Total Ratio: 24.50855 : 1
Total Motor Speed: 69120 RPM
Vehicle Speed: 48.24 MPH

Now, I have personally radared a stock old style emaxx at almost 30mph with good batteries. So it is very similar to the 6.5 motor on recommended gearing.

Now the 4.5 motor has to turn almost 70k rpm to get to 48 mph. Thats a good speed, but I do not see how the motor will last, not to mention how ineffecient it will be at 70k rpm. It must put out a ton of heat. Plus both of these motors are producing their power with higher rpm, not low rpm torque like a bigger motor would.

Lets put it this way, the best motors you can get are Neu motors, and no one uses a neu motor the same size as a hv motor in an emaxx. They use a 550 or larger size motor with a large rotor, on 4-5s lipo. And generally keep the rpm around 40k or less. The larger motor allows for gearing options and speed that the smaller novak just can't do.

The Novak HV system was designed about 4yrs? ago, for the older emaxx. Remember how good batteries were back then? The novak was setup for 2 stick packs, that maybe could handle a 30 amp load. So 14 volts at 30 amps gives 420 watts, .5 hp. Eevn if you run it on 14 cells thats only 480 watts. That was good power on crap batteries, hats off to novah for making it happen. However batteries are better and larger motors work better in heavier vehicles, try to prove that wrong.

The new emaxx is not going to go see much improvement with 480 watts. The stock titans on 16.8v should be able to produce about 300 watts at least. A feigao xl motor on 4s can push out 1200 watts.

Nuff said.
   
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