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Old 03-30-2010, 09:12 AM   #1
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Default Add motor timing or change pinion?

I have a question I could not find an answer to via searching...

What is the opinion of the experts on this: I have a Slash 4x4 running the stock Velineon 3500 bushless motor with a Castle mamba Max Pro ESC. I am currently using stock gearing of a 13t pinion w/ 54t spur and morot temps are nice and cool. If I want slightly more speed out of the motor utilizing my 4800mAh 2S Lipo, would I be better off turning up the motor timing 10 degrees or so in the ESC, or going up a tooth on the pinion?

This is not really a matter of what vehicle or battery i am using at it is applicable to all cars. It is more a questionof which option is better for speed, torque and motor heat.

Will advancing the timing on stock gearing give me more top end WITHOUT the loss of torque at the bottom end (stock gearing still)? I know it will produce more heat, but the torque is what I am curoius about...

On the other hand, will adding a tooth to the pinion make me lose torque, but gain the speed all while still getting the motor hotter than stock because of the taller gears?

Either option may have the exact same outcome, but I wanted to hear it from you guys what the consensus is.

Thanks!
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Old 03-30-2010, 05:04 PM   #2
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If increasing timing flat out in a linear fashion across the rpm band, you're going to get the same effect as a larger pinion/smaller spur. The advantage of a nice speedo comes in where you can increase timing at a certain rpm, so you still have your torque of low gearing, but get the top end timing advance. Not sure if your speedo can do this like a Tekin can, but I do believe the Mamba Pro can. To simply answer your question, increasing the timing from 0-top rpm is the same as gearing up, but do it only after a certain speed and you can do even more timing without sacrificing any low end torque and the consequential increased heat.
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Old 03-30-2010, 10:01 PM   #3
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The way that the Tekin and Mamba Max Pro ESCs advance timing is for sensored motors only. Using a sensorless motor you are stuck with whatever you set from the start.

My experience has been that timing advances will "bog" the bottom end just a bit, similar to using a larger pinion, unless you are way overpowered, then you will not feel much difference in bottom end torque. Castle recommends changing your gearing as needed, since most motors have a range of timing that works best. With the VXL motor, I think an increase in timing would not cause torque to suffer enough to notice, but a larger pinion will definitely divide your torque output. But really, for each application many people could experience different things happening. Experimentation is the only way to find what will work best for you.
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Old 03-30-2010, 11:31 PM   #4
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I don't think you're going to lose torque by going up one tooth on the pinion. Reason being brushless ESCs have Punch settings. In other words if you gear up and find that you lose punch/torque all you need to do is increase the punch level.

Most people have the misconception that brushless motors behave like brushed motors when they really don't. Brushed motors have limited torque no matter how much current you feed the motor. On a brushless motor the torque will be MUCH higher and will depend on your Battery's ability to supply enough current. That's why brushless ESCs have a punch setting ie there is so much torque that you'd want to be able to adjust it depending on your gearing. If you're just spinning the tires then torque is the least of your problems.

With that said you're likely going to get an increase in motor temps regardless which route you take.
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