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Old 09-03-2016, 08:11 PM   #76
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Here's the track I race.



It's in Brazil (Niterói/Rio de Janeiro) and here is hot as hell almost all year long. Our races are 5 minutes long and I use 5000mAh/75C and 6800mAh/40C batteries. I must keep torque control #4 to not kill my batteries. 6800mAh is enough for 5 minutes long races
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Old 09-04-2016, 12:37 AM   #77
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Quote:
Originally Posted by rnelias View Post
Here's the track I race.



It's in Brazil (Niterói/Rio de Janeiro) and here is hot as hell almost all year long. Our races are 5 minutes long and I use 5000mAh/75C and 6800mAh/40C batteries. I must keep torque control #4 to not kill my batteries. 6800mAh is enough for 5 minutes long races
ok cool track , i see you even have a tiny track in the corner!
Yea, my local track was established in 1978 so its an awesome facility they provide a large pit shed with benches and chairs , air compressors , decked out canteen , grass infield, led lighting for twighlight meets and a two story rostrum!
The club Pres and the committee run the race meetings very professionally so its
a pleasure to be a member.
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Old 09-08-2016, 06:15 PM   #78
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[QUOTE=rnelias;14659039]

p.s.: 2050 has more torque than 2250

/QUOTE]

That is surprising, a bigger and heavier motor (2250) designed for a bigger and heavier vehicle (truggy) having less torque. I suppose you have a source for your statement.
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Old 09-08-2016, 06:23 PM   #79
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[QUOTE=John Wallace2;14664717]
Quote:
Originally Posted by rnelias View Post

p.s.: 2050 has more torque than 2250

/QUOTE]

That is surprising, a bigger and heavier motor (2250) designed for a bigger and heavier vehicle (truggy) having less torque. I suppose you have a source for your statement.


source: https://en.wikipedia.org/wiki/Motor_constants

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Old 09-09-2016, 02:37 AM   #80
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[QUOTE=rnelias;14664726]
Quote:
Originally Posted by John Wallace2 View Post
I think you are under the impression that Kt is the same thing as the torque of a motor. While the Kt of your 2250 motor is certainly smaller than the Kt of my 2050 motor that does not necessarily mean your motor has less torque. Kt is NOT the motor's torque; it is the motor torque constant, which according to reference 10 in the Wikipedia link you provided is "...the ratio of torque output [r] to current input [armature current]". [] indicates where I've inserted material for clarity.

Rearranging the equation and simplifying, torque (r) is

r = armature current* 60/(2PI*KV)

Thus, you also need to know the armature currents of the two motors in question in order to use these equations to make comparative statements about their torque unless of course the armature currents are the same.

Your statement still may be correct, IMO you just haven't provided the data to support it.

Last edited by John Wallace2; 09-09-2016 at 05:30 AM.
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Old 09-09-2016, 03:05 AM   #81
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[QUOTE=John Wallace2;14664963]
Quote:
Originally Posted by rnelias View Post

I assume your statement that my 2050 motor has more torque than your 2250 is based on the Wikipedia statement that Kt in the equation in your post is the torque of the motor. Sorry, but Wikipedia has mislead you! Kt is NOT the motor torque as Wikipedia states; it is the motor torque constant which is according to reference 10 in the Wikipedia link you provided is "...the ratio of torque output [r] to current input [armature current]". [] indicates where I've inserted material for clarity. Without knowing the armature current of the two motors in question, you cannot use these equations to make a statement about the torque unless of course the armature currents are the same. .
well... maybe these charts are misleading me too

KV vs Power vs RPM

your 2050kv HAS more torque than my 2250kv

but, geared accordingly, will be as fast as mine. The only problem is that each motor has a RPM range for its best efficiency...
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Old 09-09-2016, 05:39 AM   #82
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[QUOTE=rnelias;14664975]
Quote:
Originally Posted by John Wallace2 View Post

well... maybe these charts are misleading me too

KV vs Power vs RPM

your 2050kv HAS more torque than my 2250kv

but, geared accordingly, will be as fast as mine. The only problem is that each motor has a RPM range for its best efficiency...
Like I said, your post just didn't support your statement. I've seen John's charts before and even helped edit his book. The only thing I can say that is different is that his dyno runs are done with basically the same 540 type motor but with different winds. That is not necessarily the same with the two motors we have been talking about. The Truggy motor is longer and heavier than the buggy motor. I thought it had a bigger diameter too but the Tekin site says no.

Anyway I'm more interested in how fast a motor accelerates than I am in torque and my Fantom dyno plots all have time on the X axis not RPM.

Lets discuss something more interesting, like how your setup compares to what I'm using.

I must say I'm amused by the motor discussions. The fast electric guys here are detuning their 2650 motors and are as fast (lap times) as the fastest nitro cars driven by factory sponsored drivers and are running 8 minutes without problem.

Last edited by John Wallace2; 09-09-2016 at 06:14 AM.
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Old 09-09-2016, 05:48 AM   #83
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[QUOTE=John Wallace2;14665049]
Quote:
Originally Posted by rnelias View Post

Like I said, your post just didn't support your statement.
well... though... I give up. You asked me for sources and I gave them...

They're not my posts, I just cited them and the information is there.

The second link has an extensive work in this subject. Just dive in the content to feed yourself...

cordially

Renato
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Old 09-09-2016, 07:21 AM   #84
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[QUOTE=John Wallace2;14665049]
Quote:
Originally Posted by rnelias View Post

Like I said, your post just didn't support your statement. I've seen John's charts before and even helped edit his book. The only thing I can say that is different is that his dyno runs are done with basically the same 540 type motor but with different winds. That is not necessarily the same with the two motors we have been talking about. The Truggy motor is longer and heavier than the buggy motor. I thought it had a bigger diameter too but the Tekin site says no.

Anyway I'm more interested in how fast a motor accelerates than I am in torque and my Fantom dyno plots all have time on the X axis not RPM.

Lets discuss something more interesting, like how your setup compares to what I'm using.

I must say I'm amused by the motor discussions. The fast electric guys here are detuning their 2650 motors and are as fast (lap times) as the fastest nitro cars driven by factory sponsored drivers and are running 8 minutes without problem.
I was not tracking the discussion from the start and, of course, I was always assuming motors with the same sizes
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Old 09-09-2016, 11:54 AM   #85
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Default My MGT7 Running Fastest Pass at Poseidon Motors Speed Run Challenge

Ran my MGT7 at the Poseidon Speed Run Challenge at Camarillo Airport, CA last weekend. 146 mph with my TP Power USA brushless motor on 8s. Fastest pass of the event.

https://youtu.be/UTM0ZO_-ZNc

Check out TPPOWERUSA.COM for some awesome motors and even better prices.
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Old 09-16-2016, 07:34 PM   #86
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Has anyone come up with a good way to take some additional castor out of the front suspension? I'm running a 2mm shim on my diff housing to space the front shock tower forward, I've been thing about shaving the arms as well, but I dont want to run out of hinge pin room and create an excessive amount of pill wear..... I love everything else about the car, I hate when I run it hard I feel like I can push my serpent much faster into the corner.
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Old 09-17-2016, 03:58 PM   #87
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Originally Posted by Lanky View Post
Has anyone come up with a good way to take some additional castor out of the front suspension? I'm running a 2mm shim on my diff housing to space the front shock tower forward, I've been thing about shaving the arms as well, but I dont want to run out of hinge pin room and create an excessive amount of pill wear..... I love everything else about the car, I hate when I run it hard I feel like I can push my serpent much faster into the corner.
Never thought about it since more caster is better for straitght line.
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Old 09-17-2016, 06:07 PM   #88
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I have 2 MGT7's 1 is speed run only. My 6s "speedrun"car also see's a good amount of asphalt track racing.

I also think my 8s car hooks hard left or right, as when you try to correct it, your effectively lifting contact patch of the front tires one way or the other. I realize you could run heavier front diff fluid to numb it out a bit as well... I also realize there are a million different theories on the subject. In my humble opinion, id rather have less castor on both cars...

Im currently thinking about running serpent "pills" on the upper hinge pins as they will add ~1mm forward push on the pin, and shaving 1mm off of the bottom arms and 2mm off of the upper. While don't want 0* Id like to be able to adjust 2.5*-6* respectively, hoping for better tire wear as well...
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Old 09-19-2016, 07:00 PM   #89
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Quote:
Originally Posted by Lanky View Post
I have 2 MGT7's 1 is speed run only. My 6s "speedrun"car also see's a good amount of asphalt track racing.

I also think my 8s car hooks hard left or right, as when you try to correct it, your effectively lifting contact patch of the front tires one way or the other. I realize you could run heavier front diff fluid to numb it out a bit as well... I also realize there are a million different theories on the subject. In my humble opinion, id rather have less castor on both cars...

Im currently thinking about running serpent "pills" on the upper hinge pins as they will add ~1mm forward push on the pin, and shaving 1mm off of the bottom arms and 2mm off of the upper. While don't want 0* Id like to be able to adjust 2.5*-6* respectively, hoping for better tire wear as well...
Sounds like a good idea. In the end it all comes down to what the driver is comfortable with and what the car is used for.
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Old 09-19-2016, 07:13 PM   #90
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Default Center Diff CVD Joints Getting Hot

Anyone notice their center CVD joint cups getting too hot to even touch for more than 3-5 seconds after just a few minutes of use or bursts of acceleration? I been trying to figure this out the entire time Ive had the car pretty much. I know it's normal for them to eventually get hot after usage and it could just be because my MGT7 is a speed run car that runs on mostly 8s usually making at least 12-13 HP depending on what motor I run.

I tried putting ceramic bearings in there and I leave a small amount of play between the bearing and cvd joint. My diffs are shimmed properly and not binding whatsoever. I oil the bearings often too. I have tried the MBX7 style universal shaft as well.

This problem has been bothering me every since I've gotten into 1/8 scale GTs and also happened on my OFNA GTP2E, Kyosho Inferno GT2, and Mugen MBX7.

Anyone with any idea why or have any suggestions?
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