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Old 01-25-2014, 07:56 AM   #1711
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There might be a reason for that. It sounds as if you never ran the motor in the right spot of it's powerband. Just guessin', but if you were running it on a smaller track, that's not what that type of motor was designed and built for. A motor that's taching 28k+ needs a bigger track. From what Jim has said about the tracks you typically run on, a 21 to 23k motor is probably best.

In that state of tune, the rpm to time curve is nearly linear in comparison to a stock motor. Even then you need a straight that's at least 2sec. long to have the motor peak out. An ultra hi rpm motor will be "lugging" off the powerband, getting hot and "burning" up.
I totally understand what you are saying, however I would only run them during our WCICS series, most of which have tracks with straights approaching 80-90 feet. I would also typically gear them down to take advantage of the higher RPM with better torque out of the corners. Armature temps were in the 160 F range after every run. I noticed this fall-off in both mini and in my F103 - which doesn't have the gearing limits of the M chassis. I also dyno most of my motors to confirm the powerband and best operating efficiency (I'm a mechanical engineer - don't judge me ) and gear accordingly (I still do this with brushless). Don't get me wrong - after a race weekend and a thorough cleaning, the motor is still better than practically any stock Johnson I have ever come across, it has just lost the edge against a new full race motor.
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Old 01-25-2014, 09:55 AM   #1712
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Hate to break the bad news Jim, but Doc's wundermotors are short lived on the track. I have used several, and for me they last for about a race weekend - I would use the previous race-day finals motor for the 4 rounds of qualifying and swap in a new one for mains. After that, they are nothing more than decent silvercans...
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Don't get me wrong - after a race weekend and a thorough cleaning, the motor is still better than practically any stock Johnson I have ever come across, it has just lost the edge against a new full race motor.
My apologies, but you can understand why I thought you'd totally "fried" them from your first post. While I've never run one of Doc's full race motors cause I build my own, I knew that unless they had been "damaged" in some way, they would still be much better than a "decent silver can". I'm glad that you clarified your original post.

Typically, motors with a "full race" tune on them will drop about 5%. However, since the rpms are up about 60%+ and the torque numbers are up 30%+, they should still pull a stock Silvercan by a considerable margin. This is assuming they were not "overheated". These figures are for my own motors, but can't imagine that one of Doc's motors would drop off that much.

But this is a moot point, cause you have gone to a spec B/L system and we've converted to 21.5 B/L.

Last edited by Granpa; 01-25-2014 at 09:57 AM. Reason: addition
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Old 01-25-2014, 05:53 PM   #1713
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Yup, red dot was a total dog out of the corners. (M03, 20t pinion, 60d tires, short-ish carpet track) I suppose i could've made it work better had I geared down to it. Perked up right before the end of the straight. Quite hot, even with the R1 Wurks endbell fan. Run it once and handed it off to be stuffed in a kid's car.
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Old 01-25-2014, 06:15 PM   #1714
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The new silvercan. What is the best way to break them in. Have heard water or root beer or can I do this to 1 of the 8 used silver cans that I have There is just 2 guys at the track that are way faster down the straight and can actually pull out and pass anyone else
After gaining ground through the corners it really sucks to get passed on a straight. We run fdr of 5.75
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Old 01-25-2014, 07:23 PM   #1715
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The new silvercan. What is the best way to break them in. Have heard water or root beer or can I do this to 1 of the 8 used silver cans that I have There is just 2 guys at the track that are way faster down the straight and can actually pull out and pass anyone else
After gaining ground through the corners it really sucks to get passed on a straight. We run fdr of 5.75
Many posts on this, but will see if I can separate out some of the BS.

What to use-----For most of us just plain water or water with a little Simple Green works as well as most.

How much break in-----for a daily runner, just until the brushes make full contact across the comm. Race motor----until the brush makes full contact with the comm. The brush on this motor will be much more worn away than the daily runner.

What voltage----2-4 volts. The lower the voltage the longer to takes and the smoother the comm appears. How long-----depends on the brushes in the motor. Some motors only take a minute or two. Others with the harder brushes can take upwards of 30min at 2v. It seems that all the new motors with the brushes with CS on them are hard brush ones.

You can water dip any Silvercan motor. Sometimes a motor that's been run for a long time without cleaning, can benefit from a short water dip. Just clean off the comm and then dip at low voltage and monitor by the comms appearance.

Too many different motors out there to give specific times and voltages.
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Old 01-25-2014, 09:44 PM   #1716
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Talking MIA?

Hey Grandpa,
How are you doing?
We missed you at the track.
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Old 01-25-2014, 10:24 PM   #1717
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Listen to Grandpa. He knows what he is talking about when it comes to silver can motor.
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Old 01-26-2014, 07:42 AM   #1718
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Listen to Grandpa. He knows what he is talking about when it comes to silver can motor.
Thank you for the kind words. There really isn't any voodoo to a Silvercan. Most of the "magic" stuff and the "secret" materials to treat the motor with are just BS. Getting a Silvercan to run fast is just the application of some fundamental principles.

Max, at my age, you find yourself attending funerals and visiting hospitals a lot. This time for an old friend of my wife's.

Atechbh-----for a stock Silvercan, for a TC, the right FDR is in the 4.0-4.5 range. Use a good fan like the R1 fan and you might sneak a bit lower. You should use a fan and clean the comm every run if you want to have the motor last.
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Old 02-10-2014, 06:09 PM   #1719
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Is there any advantage to running a better
Battery with a silvercan? Currently running
A thunderpower 3300mah 35c which saves
Weight but I have a 5600mah 100c I could use?
Have heard that it doesn't matter with a brushed
But just curious.
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Old 02-12-2014, 04:19 AM   #1720
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Has anybody tried using a larger mah and C rating battery vs a smaller one with a silver can?
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Old 02-12-2014, 07:33 AM   #1721
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Is there any advantage to running a better
Battery with a silvercan? Currently running
A thunderpower 3300mah 35c which saves
Weight but I have a 5600mah 100c I could use?
Have heard that it doesn't matter with a brushed
But just curious.
Don't know who could have told you that. Batteries work the same way, no matter what kind of motor is being used. Generally speaking, the higher the C rating and the larger the capacity, the better the battery performs. The question is if you can believe the label.
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Old 02-12-2014, 02:50 PM   #1722
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Comes down to power to weight.

With a silver can you may find the higher capacity battery adds more weight and the car is slower, similar with thicker heavier wires.

If you remember NiMh days mod went to 5 cell over 6 cell, less power but less weight and the result was a faster lap time.
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Old 02-12-2014, 03:56 PM   #1723
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There's a possibility of some gain, perhaps towards the end of a long run when voltage sag rears it's ugly head, but I'd suspect it would be minimal and offset by the extra weight.
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Old 02-12-2014, 04:20 PM   #1724
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It's pretty much about area under the curve in terms of voltage. The larer capacity battery will deliver a higher average voltage over the race time. It helps to have an idea of how much capacity you are using during the race.

Example: When TCS F1 was foam tires and silver can motors, on carpet an 1800 mah mini revo pack was awesome. It weighed about 100g less than almost any other battery allowing you to hang some gear on the motor. Not to mention we were really fast on 15000 rpm motors, lol. Some tracks this was worth .3-.4 sec. per lap.

I think we used 800-900 mah. It was also obvious when your pack was getting old.

Enter brushless 21.5 on foams. This setup is now worthless, the battery goes soft during the run and your toast. BL is usually somewhere around 1100-1200 mah for a run. The amp spikes might have been high for a 25c pack as well (I don't trust C rating other than an indicator of what kind of IR the pack is probably carrying).

To be honest we were probably close to the usable capacity of the 1800 battery with silver cans. BL was just a no go.
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Old 02-12-2014, 04:31 PM   #1725
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Weird, we found the opposite when we switched to BL. Battery use was lowered significantly. Could be the specific fixed timing motor we chose or the fixed gearing that makes the difference though.
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