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Old 11-28-2014, 09:00 PM   #8071
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Originally Posted by spurcheck View Post
I like that the cars are running at a more realistic pace, more door to door racing, you aren't chasing the "motor of the week" and more emphasis is on chassis set up and making wise choices on the track.
And they just simply look cool.
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Old 11-29-2014, 11:15 AM   #8072
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Quick question on gearing.
On a tight carpet track, are most cranking the timing all the way up and gearing from there, or leaving the timing lower and adding teeth to the pinion for more torque?
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Old 11-29-2014, 11:20 AM   #8073
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Quick question on gearing.
On a tight carpet track, are most cranking the timing all the way up and gearing from there, or leaving the timing lower and adding teeth to the pinion for more torque?
Good question. I want to know the answer to this too.
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Old 11-29-2014, 11:25 AM   #8074
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I have never heard of a USVTA motor NOT being at max timing. Regardless of track.
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Old 11-29-2014, 12:04 PM   #8075
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I'm sure I will get blasted for this BUT...just like with any motor they all have a "sweet spot" and it isn't always at max timing. you can change the timing while you have the throttle wide open and hear when it hits that "sweet spot" and if you go beyond it will start to lag.
Just my $.02 worth here, be kind.
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Old 11-29-2014, 02:57 PM   #8076
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I have never heard of a USVTA motor NOT being at max timing. Regardless of track.
hate to bring this up again but max timing is what 45 degrees on the label or what?. Because of issues with the timing label placement 45 degrees was actually 58 degrees on one of my VTA motor and 55 on the other. Neither ran particularly well with that much timing. I set the timing at 45degrees with the Motorlyser, and the motor seems very happy there coming off the track barely warm after winning a 12 minute main with no fan. I've seen people running the same motor: one at max timing and the other at zero timing and be equally fast when gears appropriately. Is 45 degrees the sweet spot, I don't know, but its close.
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Old 11-29-2014, 03:26 PM   #8077
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Originally Posted by theproffesor View Post
I have never heard of a USVTA motor NOT being at max timing. Regardless of track.
I have never ran max timing....Mike is absolutly correct. The sweet spot for all these can be anywhere.

But max time is rarely it for me...I average 25-37deg give or take and the track condition
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Old 11-29-2014, 03:36 PM   #8078
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Originally Posted by John Wallace2 View Post
hate to bring this up again but max timing is what 45 degrees on the label or what?. Because of issues with the timing label placement 45 degrees was actually 58 degrees on one of my VTA motor and 55 on the other. Neither ran particularly well with that much timing. I set the timing at 45degrees with the Motorlyser, and the motor seems very happy there coming off the track barely warm after winning a 12 minute main with no fan. I've seen people running the same motor: one at max timing and the other at zero timing and be equally fast when gears appropriately. Is 45 degrees the sweet spot, I don't know, but its close.

dont see what you are saying. your sticker didnt match up with what the dyno? why would it? your motor was hand made by people with different hands. what makes you think that they all are the same strength to pull the wire the same tightness? if your motor is off, its not the end of the world. nor is a black eye on the class. its just what it is.

i hope that you guys that come on here and find complaints and goofy loopholes within the USVTA and USGT classes know you are just hurting the growth of the classes. you are not doing any of us any favors by constantly complaining and whining about this and that.

The rules are simple and easy to follow. I dont agree with the change in the esc ROAR rule. but I respect Robk and Eric and thats the bottom line for that. Im I going to quit VTA...no...complain...no....I got over it real quick and raced within the rules. simple

yawn...cya
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Old 11-29-2014, 05:47 PM   #8079
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I guess i am not seeing where the guy you quoted was complaining?
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Old 11-29-2014, 07:19 PM   #8080
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Well I stand corrected. Everyone at my local track cranks um to the moon and beyond.

Long live USVTA and USGT.
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Old 11-30-2014, 04:19 PM   #8081
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Originally Posted by DARKSIDE View Post
I have never ran max timing....Mike is absolutly correct. The sweet spot for all these can be anywhere.

But max time is rarely it for me...I average 25-37deg give or take and the track condition
If you are talking about timing label timing your sweet spot could be at or near the old MAX timing limit of 45 degrees and not realize it. My VTA motor at 45 degrees timing by the Motorlyser, says ~33 degrees by the label. Sweet spot or not, it runs strong all the way through a 12 minute main (5000MAH battery).

PS ROBK announced he was revoking the 45 degree timing rule here in this thread about a month ago because of issues with the timing label. Not complaining or whining here; just stating facts.

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Old 11-30-2014, 08:04 PM   #8082
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Originally Posted by hairy View Post
I'm sure I will get blasted for this BUT...just like with any motor they all have a "sweet spot" and it isn't always at max timing. you can change the timing while you have the throttle wide open and hear when it hits that "sweet spot" and if you go beyond it will start to lag.
Just my $.02 worth here, be kind.
Read this yesterday so when I was working on my cars today I decided to test this out.

Loosened up the screws on the motor and held the throttle wide open with one hand while I twisted the motor with the other. The "Max RPMs" point of the motor was with the mark WELL past the 45 point on the label. I'm talking like 65 or 70 before RPMs started to go down. It was actually fairly easy to eyeball max RPMs based on tire ballooning.

Also, each motor didn't hit this max RPM at the same spot so I'm in total agreement that the labels are crap.

So my question now is: Is max RPMs equal to "sweet spot"? Why would you run with less than max RPM other than heat?
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Old 11-30-2014, 08:09 PM   #8083
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be curious on that question too.

Also, when you guys do this test for "Max RPM", I am assuming this is under load on the vehicle and would this be a valid "quick and dirty way" to find the sweet spot for your timing setting.

With this much variance in the motors, glad that timing on the can is able to be adjusted. Could imagine the complaints or people hunting for the best motor then for ones that have a fixed timing but don't behave the same way at that timing setting.
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Old 11-30-2014, 08:32 PM   #8084
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Originally Posted by .crispy View Post
So my question now is: Is max RPMs equal to "sweet spot"? Why would you run with less than max RPM other than heat?
No, maximum RPM with no load is not the sweet spot. You need to find the timing setting where the product of torque times RPM (also known as power output) is maximum. The only way to find this point is under load. If you don't have an accurate, true dynamometer, then it's a matter of track testing at several different timing settings and gear ratios.

Tidbit: the maximum power output of a permanent magnet DC motor is at 1/2 of the free-running RPM.
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Old 11-30-2014, 08:41 PM   #8085
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what tools do you guys recommend to have to do this that doesn't break the bank?
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