motors motors motors

[shenlonco 1173]

Hi guy's maybe somebody can help me out here I just want to know the speed gains you will get between these motors.

i am running stock ESC and stock 540 kit motor in a lunch box...

about how many MPH faster will my lunch box go if i swap out the stock 540 to a J Johnson motor and how many MPH faster from the J johnson to the better sport tuned motor?

THANKS

Shen

[GregM 1109]

I have three different looking silvercans from Tamiya kits (one with shiny finish and the big Mabuchi sticker, one Johnson, and one with dull/flat finish and just a "Caution Hot! Motor" sticker), and I think the differences between them are just minor. To get a noticeable gain in speed, you should better try a Tamiya Sports Tuned motor (or similar).

Speeds will vary depending on car weight, transmission, pinion size and wheels. For example, a lightweight Hornet with its solid rear axle should be faster (in a straight line on tarmac) with a silvercan than a Sand Viper using the same motor.

[bromvw 744]

i think i'd go for a tamiya sport tuned motor (black can ) . They are readily available and well priced . This will give a decent speed gain .

[shenlonco 1173]

Thanks guys... I learned the HARD way

I have a lunch box and a pumkin less than 2 monthes old each not used to many times... I drag raced them against each other and they where the same speed and then i put a J johnson hop up motor in the pumpkin after braeking it in on my motor break in machiene for 60Min at 1.2V

GEUSS WHAT drag raced them again and the two trucks are exact same speed...no speed gain...BUMMER black can sport tuned motor is the way to go for sure!

[andy_t 2]

Hi guy's maybe somebody can help me out here I just want to know the speed gains you will get between these motors.

i am running stock ESC and stock 540 kit motor in a lunch box...

about how many MPH faster will my lunch box go if i swap out the stock 540 to a J Johnson motor and how many MPH faster from the J johnson to the better sport tuned motor?

I think once upon a time the 540-J motor was considered a hop-up, more for torque than RPM, but I never fully understood the difference between that and a standard 540 motor that happened to have been produced by Johnson, rather than Mabuchi.

Many, many years ago I put a Technigold in a Hornet and turned it into an uncontrollable missile - although on maximum attack it drained the humpbacked NiCd pack in under 10 min. I just put a Sport Tuned in a re-re Hornet and that didn't seem like quite such a difference, but the Hornet has gone from "quick" in a straight line to "very quick", and it gets up to a good 40 km/h in under two seconds from rest. Perhaps a 15% increase in top whack.

[TamiyaDan 8]

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[shenlonco 1173]

Great write up I do know this and i do feel the J has more torque it pops up the truck a little more so it probably will push a larger pinion gear and make another car get a little faster with the option of changing gear ratios.... so in the dirt and short grass the J motor probably will pull the truck through it a little faster.

Funny i have a RPM checker and the J motor is 4000RPM less than a black sport tuned motor.

and on my motor break in macheine AT 1.2V the J motor draws .69Amps and the sport tuned draws 1.29amps so i can tell the black motor most lily will be a much faster motor.

I just think fro the price on e-bay for 2 bucks more you can get the black sport tuned motor so i think that's the best way to go.

i dynoed both motors about a year ago, the Johnson has more brush hood timing then the regular 540 silver can.

what that means is it makes slightly more power then the regular silver can motors.

both torque and horsepower showed a gain.

how much was negligible depending on what you compared both motors too

what that translated into is this. If you have an adjustable gear ratio on your car or truck, you could gear up the johnson J motor by 1 tooth compared to the regular 540 motor.

the johnson also makes Slightly more RPMS, but you have to figure load and real world friction would drop both motors that are so close into the same RPM range, and the difference is in the Torque.

However in this case we are talking about a lunch box or midnight pumpkin, Fixed gear ratios.

in this case the motors are close in spec and use the same gear ratio, although the johnson has the torque advantage it is not being used because you cannot gear up the pinion.

so the result is the motors appear the same.

when you go to a higher rpm range compared to both motors then you will see one motor faster then the other with the same gear ratio.

so the sport tuned will show a speed increase.

sport tuned

18,300 rpm at best efficiency

350 g-cm torque at 18,300 rpm

peak rpm: 21,000

J motor

RPM at Best Efficiency: 14500 RPM @ 7.2V

Torque at Best Efficiency: 255g-cm @ 7.2V

Current Consumption at Best Efficiency: 7.9A @ 7.2V

4000 rpms in the real world would translate into another 1000-2000 rpms under the same ratio so you would see a speed increase.

the stock 540 is in the 13,900 to 14,000 range so it would be hard to see the advantage unless you let both trucks run out full speed for say 1/4 mile by the end the higher rpms from the johnson would see that car ahead of the 540 truck.

pointless for 100-200 feet of driving most of us do.

now if it was possible to change the gear ratios in those models then you would see the differences, but its minor for messing around, on a track it can make the difference between DNF from a battery dump or a win.

you would have to be careful not to go too hot a motor with a fixed ratio as well. The danger is in thinking a 13 turn motor can make over 50,000 rpms so if i put that in my truck it will go super fast.

however a low turn motor Trades Torque for RPMS without changing the gear ratio the truck would go slow and the motor would burn up from the load, your battery would dump fast and you may melt the plastic housing on the gearbox as well.

[TamiyaDan 8]

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[shenlonco 1173]

I know all this already i been into RC for over 30 years.

These tamiyas with stock brushed motors are my have FUN rc's i have lots of others with brushless systems and nitro.

I would not bother with any brushed motor but for these tamiyas i feel a brushed black sport tuned motor will be pleanty enough.

I can't see trying to control a brushless lunch box or FAV or scorcher or a hornet with a brushless syetem enless you get like a 2600 or 2700KV motor and that will be pleanty for the tamiyas.

Shen

those motor break in machines and rpms checkers are basically worthless, other then breaking in brushes to the comm surface.

to test a motor, you have to test it under load, and under the amps that the motor will see 90% of the time.

for offroad you have to test motors under 20-30 amp loads, for onroad 15-25amp loads.

in that range is where you will see what a motor can do. Free spinning the motor will show unloaded specs, and give no useful information, and can actaully hurt performance if you use it as a tuning tool to gauge performance by

that is why its such a lie to use that type of motor tester. usually they tell you to tune a motor to increase amps so most guys experiment and throw on a set of heavy brush springs or soft brushes, which produce less arc and more commutator surface contact and also no brush bounce. so your amps show a huge increase, you take the motor outside and the car runs HORRIBLE its slow, gets hot, battery dumps. etc.. its because you did not tune for usable load you tuned for a no load situation.

without going into pages of detail and also because now brushed motors is a totally lost art thanks to brushless motors, basically there were 3 types of hobby quaility motor dynos worth getting back in the day, one tested with a flywheel load the other tested with a slave motor load.

the flywheel verse slave motor load would generate totally different data sets, there was no standard, basically you had to build up a history with each machine to have baselines to compare a motor to another.

once you had baselines then you could throw a new motor on and make changes and really see a comparable difference in tunes, then because you had the baseline information you could calculate the correct gear ratios to start a practice session on.

personally the entire thing was a huge Pain for a hobbyist, and pure badword if you were your own mechanic at the tracks the uber sponsored guys had dedicated motor builders and would show up at the track with boxes and boxes of motors for practice sessions to get a new baseline generated for a new track. then they crunched the numbers of 1000s of lap times and came up with a winning motor formula.

nobody is doing that anymore brushless changed everything.

people i know that got into motor building Quickly got back out of it and sold equipment off at huge losses.

the truth is for the average competition racer.

to make a motor run well, you need:

1) brush hood alignment.

2) break in the brushes.

3) comm cutter.

4) motor cleaner.

5) bearing oil, or bushing break in fluid.

that is it. all the Comm breakin fluids are just dish soap mixed with water, it was an old slotcar trick from way back.

just aligning a brush hood correctly to the comm will give a 3-5 degree timing increase because the tolerance from the factory on any electric motor is REALLY bad.

it was why getting a hand built motor back in the day was such a big deal if you knew how to use one.

you have to be heavy into maintenance on motors, 1-2 runs on a mod means your cutting the comm again, you can cut it maybe 5 times then the motor is done.

the fact is after the initial brush break in, your suppose to cut the comm, Instant 2 Degree timing advance on a fresh motor, its going to scream.

anyhoo don't put too much into those rpm reading on brush break in machines it is just eye candy.

[TamiyaDan 8]

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[shenlonco 1173]

if you want excitement, the Sport motor isn't going to give you it.

a fun mess around motor would be in the 22-18T range. super sport.

Venom is the last brushed motor maker they make some great single and double winds in that range.

all the other big makers are doing brushless now. so Venom is the last show in town, unless you buy old stock from ebay or a local hobby shop that has been sitting on it for a while.

if you can jam a 550 Can in the lunchbox i would do it the extra torque will help with wheelies

before going to do that with a brushed motor i would just pick up a $60.00 Ez run brushless system or just the esc and put in a 2700KV motor 2700 X 7.2V would be a 19,440RPM motor should be good in a tamiya.

[andy_t 2]

if you want excitement, the Sport motor isn't going to give you it.

Well it all depends on what you're fitting it into

I have a Sport Tuned motor in a Hornet, and with a 3000mAh Ansmann battery it reaches top speed in a couple of seconds, depending on launch and surface/grip; it weighs so little that I can't see any point in anything faster, as it just isn't built for 30+ mph running and goes into orbit if you hit a big divot. A shame you can't change the gearing to turn all those revs into torque at the axle. A brushless system would certainly be exciting, if you could get the power down, but I envisage a lot of backflips...

[shenlonco 1173]

I am not bothering with anymore tamiya motors you can get much cheaper ones that work mnuch better,,,,what i found

did a test i put a electrix rc 20 turn motor in my midnight pumpking and ran it in tall grass i had no problems at all??

the electrix 20 turn motor has a fan biult in but it's the short style can not the long type like traxxas uses,,,, the motor in tall grass was cool just a few degrees over 100Deg

Reason why i gave this a try is because i seen the specs on tamiyas ESC and it said continuous farward current 60AMPS and i know other brand ESC's with this type rating can use a much lower turn motor than what tamiya states as no lower than 25 turn motor.

you can find the electrix rc 20 turn motors on e-bay for a good price they come up all the time.... think i found a cheap motor alternative to the tamiyas.

I also have a 20 turn duratrax motor i know it draws a little more amps free running at the same voltage .ike .20 amps more so that's why i used my electrix rc motor but you probably can use the duratrax or even the traxxas 20 turn stinger motor.

[shenlonco 1173]

Well just did another test with the 20 turn duratrax photon speed 2 motor and here is how it goes compaired to the electrix rc 20 turn

in my pumpkin

electrix 20 turn pills max 29 amps with my watt meter when driving tamiya stock ESC rated for continous 60 amps so these motors should be fine

duratrax 20 turn 28. something almost the same on the watt meter

duratrax RPM at the wheels is 200rpm faster

so best motor for the bang for the buck is the $11.99 sometimes free shipping on e-bay duratrax photon 2 speed motor.