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Old 01-24-2017, 07:15 PM   #1
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Default LRP X20 17.5 Blinky... help!

I'm switching from a Trinity, have a new X20 17.5 to try, TC stock (xray T4), Blinky class. All my research about "stock" motors says... "you want to adjust the timing, so it pulls 6A without load". This seems reasonable accurate, based on a couple other 17.5T I've run. The X20 comes with 5 timing choices, 27.5*-37.5*, and the most I can get it to draw, with NO LOAD is under 3A. Obviously I can gear it accordingly, but who has experience with these?? Are they designed to be geared high, hence lower current w/o load?
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Old 01-24-2017, 08:03 PM   #2
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I'm switching from a Trinity, have a new X20 17.5 to try, TC stock (xray T4), Blinky class. All my research about "stock" motors says... "you want to adjust the timing, so it pulls 6A without load". This seems reasonable accurate, based on a couple other 17.5T I've run. The X20 comes with 5 timing choices, 27.5*-37.5*, and the most I can get it to draw, with NO LOAD is under 3A. Obviously I can gear it accordingly, but who has experience with these?? Are they designed to be geared high, hence lower current w/o load?
I would put the two dot insert in the motor, that's 37.5 degrees of advertised timing and pretty much the sweet spot for my X20.

Measuring the amp draw at free spin is good for determining if your motor may be overtimed, because at some point the efficiency drops like a stone without significant power gains, but may not be the definitive way to determine the best timing. I set my 17.5 to about 2.5-3 amps of draw as a start point, some like more, but its always decent.

Also, the way you time the motor up further than the two dot is to put the insert in upside down, if I remember correctly.
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Old 01-24-2017, 08:21 PM   #3
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They are by now a pretty dated motor, so your best bet is just to gear up with what you can.
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Old 01-24-2017, 08:25 PM   #4
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They are by now a pretty dated motor, so your best bet is just to gear up with what you can.
That they are. My old X20 motor is aggressively average, and that's running it as hard as it will go with a good battery. It feels like it makes good mid range torque to pull you out of corners, but that may just be the car or how I drive it compared to others.
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Old 01-24-2017, 08:27 PM   #5
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I would put the two dot insert in the motor, that's 37.5 degrees of advertised timing and pretty much the sweet spot for my X20.

Measuring the amp draw at free spin is good for determining if your motor may be overtimed, because at some point the efficiency drops like a stone without significant power gains, but may not be the definitive way to determine the best timing. I set my 17.5 to about 2.5-3 amps of draw as a start point, some like more, but its always decent.

Also, the way you time the motor up further than the two dot is to put the insert in upside down, if I remember correctly.
Yes, I was playing with the inserts (upside down), and can get more timing, but didn't want to do anything to damage the motor, before I've even had a chance to try it. I'll likely try it at 37.5 & go from there. If it runs cool, maybe I'll start flippin' the inserts. I HAVE come across numerous comments on 17.5 "tuning", always saying "the sweet spot is 6A draw, no load", but I am not speaking from experience
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Old 01-25-2017, 04:46 AM   #6
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I have the same motor at 37.5. I have it geared really aggressive. The LRP instructions say don't let the motor get over 180 which is REALLY hot. I don't let it get near that. Our tracks tend to have more corners so I gear it for torque and it doesn't have a problem keeping up. I do find the inserts really annoying though.
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