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Old 01-10-2011 | 04:38 PM
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jmackani
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From: Shippensburg
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Originally Posted by 117
First off, I have to say woohoo!! This car is a hoot to drive. Much, MUCH more fun than my RC10B4. The RC8Be is so much more stable at speed and it can really put down the power! I was able to run full blast down my street without too much drama, and I was able to stay fully in control. Brakes were too aggressive and locking up, but that's just an adjustment issue. Tires were ballooning like crazy, so the next set for the street will need to be taped, belted, or foams. It was waaaaaaaaay too fast for being any use on a track or in the dirt. Setup is 6S Zippy 40C battery, MMM w/1800kV Neu motor, 21T pinion, stock 46T spur, ProLine Road Rage tires on ProLine V2 wheels. The tires were out of balance as well, and I could tell at high speeds.

Doug, I'm glad I can help now since these guys have helped me quite a bit.

I would HIGHLY recommend the EFlite EC5 connectors. 5mm barrel connectors that are easy to solder, easy to connect/disconnect, and they seem to handle the power, no problem. The connectors were not any hotter than the wires after this last run I had.

Not sure if 60C is going to be worth the additional cost over 40C. My car had TONS of punch and seemed to get up to full speed very quickly. For this car, I'd use as large wire as you can. At least 10 gauge (IIRC, the batteries I bought are wired with 10 ga). Heck, I'd use 8 ga if it would fit! I also like a single battery to make the wiring more tidy.

As for pinions, I used what Grid recommended, and they seem to work very well. I ended up buying Hot Racing 1M 17T, 19T, and 21T pinions. Definitely not cheap, but they are very compact, appear to be well made, and I didn't have any problems with the set screw backing off during this run.

I didn't use the Kyosho gasket (although I think you might be thinking of the Kyosho red o-rings, which were recommended until AE updated their o-rings to the clear ones). I highly recommend the Mugen gaskets. They're made with real gasket material vs. the AE paper gaskets.

Now, on to my questions.

Given the setup above, after a bunch of full throttle blasts down the street, and a bunch of heavy throttle accelerations here and there, I brought the car in. Ambient temp was around 35F. Here are the temps:
Motor - 150F on the case, 162F on the end bell
ESC - 118F at the bullet connectors, 110F around the battery side
Batt - 110F around the shrink, 115F at the exposed end
Wires/connector - didn't feel hot at all, maybe warm, but my hands were cold from being outside! I did not measure with the temp gun.

These seem a bit high to me since the ambient temp was so low. No vents or anything in the body, and there wasn't much intermediate driving (i.e. lots of blasts, then very slow driving, so not much air flow after the full throttle passes). I didn't notice the fan on the ESC at all, but the Savox servo is pretty loud, even at idle. What do you guys think?

It was insanely fast, but I'm thinking about buying a couple more sets of 6S batteries. For the track, I can see how 4S would be PLENTY.

Also, the MMM seems to stutter a bit in certain situations. For instance, if the car is coasting backward, and I give it some throttle, it'll stop the car from coasting back, stutter a bit, then start going forward. The stuttering seems to happen mostly with any change in direction, or right after putting on the brakes to a complete stop, then attempting to move forward slowly. This is a bit surprising to me as the MMP in the RC10B4 never seemed to exhibit this behavior. I don't think it's the battery, and I tend to think that it's the fact that it's not sensored. What do you guys think?

EDIT: I just hooked up the battery to the car on the bench, and gave it a go. Even with very, very little throttle, the motor and everything turns flawlessly. No stuttering at all. Tried going backward then immediately forward, worked perfectly. Sometimes a tad bit of hesitation during the back/forward transition, but no stuttering. Now I'm confused...
Running sensorless will cause the stuttering/cogging that you are experiencing. I would also recommend putting some holes in the body. I race normally and we almost always have to put holes in the body to get air into the esc and motors.
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