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Inconsistent Run on Super II

Discussion in 'Technical Help' started by Shirokumakko, Dec 4, 2017.

  1. Shirokumakko

    Shirokumakko Screw

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    I just finished building the Super II Chassis with Plasma Dash & 3.7:1 Gear, but i cannot get consistent run i need help to see if my motor is running as it should.

    Now I'm not trying to improve the car but want to make it consistent and most important to check everything is performing like it should so here are the spec:

    Car: Shirokumakko Super II
    Weight (with batteries): 130g
    Motor: Plasma Dash
    Gear: 3.7:1
    Hollow Mid Shaft
    Metal Hex Ball Bearing
    Batteries: Sanyo Eneloop
    Reinforced Pinion & Gear set (Black)
    Rest are stock

    I'm running on Speed Testor and i get random results on different sessions...

    1st day: 35km/h (3.5:1), no break in just Tamiya Grease. notice same day later sessions the speed will keep dropping.
    2nd day: 38km/h (3.7:1) changed the gear as i mistaken light blue as highest gear. Got between 37-38km/h but did not run long.
    3rd day: decide to take the motor out to "break in" without load. spraying RP7 while it's running, did x3 2-3 minutes forward & x3 2-3 minutes reverse. Dip the motor (half filled) into Zippo Lighter Fluid for cleaning. Then i added Semi-Synthetic Engine Oil into it and let everything settle & grease the gears up.
    The speed is now back to 35km/h... and after a while it's now back to 30-31km/h even after swapping the batteries.

    So I'm baffled how inconsistent my car is. i'm not sure if the Speed checker is giving inconsistent readings and since the Speed Checker is also New does it affect the consistency?

    I know the Eneloop aren't the best batteries for Plasma Dash but why the big difference in speed?
     
  2. Chris Lee Design

    Chris Lee Design Aluminum Lock Nut

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    Lots of variables but lets start from the top.

    1) Make sure every run, the batteries are charged the same way and are the same voltage every time you test otherwise your whole experiment is ruined. (Try to use tried and true batteries. New batteries can become stronger as you use them before they reach their peak.)

    2) I would stick to 3.5:1 for speed testing. You'll never be able to know exactly how fast your car is on a track because of each track being unique. On paper, a 3.5 maybe faster, but on the track the 3.7 might do better because of the layout.

    3) How many times are you running the speed test on the checker? I suspect if you were doing this for over 5 min, you already broke in the motor, it usually takes about 5min or so to break in the brushes. I don't have any experience with the plasma dash (because they are banned where I race) but some of the motors like Jet dash need extra break in time compared to the regular legal motors.

    4) How hot your motor gets will effect the speed outcome as well.

    5) re-oiling the motor is crucial especially if you're spraying contact cleaner on it.

    6) how you hold the car to the checker and how much pressure you apply effects the results as well.

    All these things effect the outcome.
     
  3. Shirokumakko

    Shirokumakko Screw

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    1.How do you check the batteries? i have a multimeter will it work? should check the V or Amp?

    2.Isn't 3.7 have higher top speed than 3.5?

    3.For Speed Checker i at most test it 5 times in a run. On my last run i was frustrated so i just left it running on the checker until battery runs out, it wasn't going that fast when i left it. New charged batteries still give 32km/h though no longer able to get 35km/h so beating the record 38km/h seems not possible. used multiple batteries. 32km/h is the best i can do right now.

    4,Usually the batteries cannot maintain the plasma dash at peak speed for long time, maybe 2-3 minutes you start seeing the speed drop. Seems the speed only goes down even after waiting half a day before another run.

    5.I used semi-synthetic engine oil after the off load break in. my dropper not very thin to reach the inside but oil does go in. also greased up all the moving parts with tamiya default grease.

    6.I tried various ways of testing. seems the car isn't stable without the body. it can stay on the checker on it's own i do hold the rear rollers to reduce the shake and the highest speed i got was having the front bumper touching the front wall so the wheels run on 4 rollers on the checker instead of 6, that is how i got 38km/h but i cannot repeat the same feat.

    Also do you really need to do those break in motor thing shown on youtube? mainly running the motor free load for 3 mins and keep spraying contact spray and adding oil then soak in zippo lighter fluid and reoil? is it not possible to properly break in the motor just by running it with the car (like normal cars) and just clean it/reoil afterwards? I know the purpose is to get stable rpm on the motor and improving the output of the motor is not really the main point. Also is it normal the moment i spray RP7 into the motor it gets a temporary boost (few seconds) as that is what i noticed.

    Also anyway you can tell if my car is running properly based on the data i provided? i just want to know everything is OK because the speed checker is telling me the car is not consistent...

    Virgin Run average 35km/h, Max 38km/h, now average 30-32km/h...
     
  4. Chris Lee Design

    Chris Lee Design Aluminum Lock Nut

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    1.How do you check the batteries? i have a multimeter will it work? should check the V or Amp? Yes, multimeter (volts) or having a special charger like (skyrc nc2600) these chargers display the voltage when you pull them off the charger.

    2.Isn't 3.7 have higher top speed than 3.5?

    No, 3.5 is higher top speed, 3.7 is slightly more torque, slightly less top speed.

    3.5 = Highest Top Speed, Lowest Torque
    5.1 = Highest Torque, lowest top speed.


    3.For Speed Checker i at most test it 5 times in a run. On my last run i was frustrated so i just left it running on the checker until battery runs out, it wasn't going that fast when i left it. New charged batteries still give 32km/h though no longer able to get 35km/h so beating the record 38km/h seems not possible. used multiple batteries. 32km/h is the best i can do right now. What is your goal with these tests? What are you trying to accomplish? Are you just trying to find the fastest motor? If so, this type of testing is not good for that. If you want to test motor, download the app "Giri" and use it to measure RPMs of the motor. Just make sure the battery is the constant in your test and is always the same voltage.

    4,Usually the batteries cannot maintain the plasma dash at peak speed for long time, maybe 2-3 minutes you start seeing the speed drop. Seems the speed only goes down even after waiting half a day before another run. That's because plasma dash drains the most amperage from the batteries. If you look on the packaging, all the motors have the amp draw written on them. Plasma dash hogs a lot of power to run even the big capacity batteries wont last very long.

    5.I used semi-synthetic engine oil after the off load break in. my dropper not very thin to reach the inside but oil does go in. also greased up all the moving parts with tamiya default grease. I would use something not as viscous. The copper bushing expands during heat so when the motor is hot, is the best time to oil. Try sewing machine oil or something like it. Just remember when you spray the contact cleaner you are drying out the bearing.

    6.I tried various ways of testing. seems the car isn't stable without the body. it can stay on the checker on it's own i do hold the rear rollers to reduce the shake and the highest speed i got was having the front bumper touching the front wall so the wheels run on 4 rollers on the checker instead of 6, that is how i got 38km/h but i cannot repeat the same feat. I haven't found a way to use the speed checker reliably. Some people cut it in half or modify it to fit a open class car. Personally, I think the best way to do it is to let the car run on it's own without you having to hold it.

    Also do you really need to do those break in motor thing shown on youtube? mainly running the motor free load for 3 mins and keep spraying contact spray and adding oil then soak in zippo lighter fluid and reoil? is it not possible to properly break in the motor just by running it with the car (like normal cars) and just clean it/reoil afterwards? I know the purpose is to get stable rpm on the motor and improving the output of the motor is not really the main point. Also is it normal the moment i spray RP7 into the motor it gets a temporary boost (few seconds) as that is what i noticed. This is one of those questions I cannot not answer as there are many ways to achieve the same goal. Those vids saying break in 3min front back etc... I've done it before and I can't say that it's the best way. I can count about 6 different ways to break in the motor, you just gotta try them all and figure out what works for you.

    Also anyway you can tell if my car is running properly based on the data i provided? i just want to know everything is OK because the speed checker is telling me the car is not consistent...This is not the typical way someone tests their car and to be honest, doesn't have any real world application (I'm only talking in the perspective of racing) You could get 45km on the speed checker and lose to someone on race day. I personally think the best way to see is to race fast people. I know in our racing community who the fast guys are so I'll race with them to keep tabs on myself. This or lap times but you'll need other people's lap times to compare on the same track.

    Virgin Run average 35km/h, Max 38km/h, now average 30-32km/h...
     
  5. Shirokumakko

    Shirokumakko Screw

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    hi, i'm just playing around to see what is the fastest speed my car can go and checking if everything is working as it should. this car is heavy since i painted it so it's not for track more of a "show car" though the oil spraying all over the car kinda ruined the looks abit esp undercover (is it normal for grease/oil to spill around when running?). since Plasma Dash suppose to be the most powerful motor i just want to see how fast a car can run based on Tamiya original parts. even without the top body i notice the top speed did not change much or even slower due to less weight. only parts i have yet add are the hollow shafts i think i added all the parts available for top speed test.

    do you have any idea fastest speed a car can run on the speed checker with All Original Tamiya parts?

    i will build other cars for track.

    also is hollow shafts & transmission shaft recommended or do you use the original or Black? are shafts? are spacers recommended between the wheel & bearing? can the 60mm shaft hold the wheels when spacers are added since it reduces the length the shafts goes into the wheel or do you need a 72mm shaft with drilled wheel?
     
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  6. yao wei

    yao wei Spacer

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    this battery is not race legal. but just to feed your curiosity, might as well post this.
    credits to zen bluster
     
  7. Drew

    Drew Carbon Fiber Dust

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    There's also the Lithium-Ion batteries you can get in AA form factor, they're not this powerful but they still pack more of a punch than regular NiMh batteries. But again, they're also not race legal.
     
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  8. Soybi

    Soybi Spacer

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    no idea about all original tamiya parts top speed since as far as i know, speed doesnt rely if the part is original or copy or non tamiya. specially on motors. there are lot of faster motors than tamiya plasma motor. so if you just want speed go buy a china aoda type motor which has more than 65k rpm if you're not joining any official Tamiya high speed races. but if you want to join an official tamiya high speed race, then i think its better to use ultra dash even though plasma is faster, you can use lighter batteries with ultra and it will drain batteries fast unlike the plasma.

    yes it is recommended ti put washers or roller spacers between bearing and wheels, and it is better to use 72mm shaft. and if you want less weight, go for hollow prop shaft, but if you want stronger and more durability, dont use it.

    you can check Mad Tang's High Speed setup guide for further info when it comes to official tamiya high speed race setup. and he has better explanation as well for each and every purpose of his setup.
     
  9. yao wei

    yao wei Spacer

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    i just want to share my observation.
    i bought 1 plasma dash 1 power dash 1 sprint fash and 1 ultra dash
    opened them, then test their rpm out from the box using giri app
    plasma registered 30k rpm
    ultra registered 34k rpm
    sprint registered 31k rpm
    power registered 27k rpm

    batteries used is energizer nimh 2000mah
     
    Last edited: Mar 12, 2019

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