porky-ninja

i wolud like to know if the in field is about the same. I know straight away speed is different. I would like to know if i could keep up to 12 -13 turns in the in field? I wold be talking about a good tuned 19 compared to a epic 12-13 or something like that. I need help. thanks

fatdoggy

It depends on the track, but I doubt it. If the cars are dialed then the 12t would have more acceleration, thus having an advantage.

IMPACTPLAYR

iTrader: (7)

A general misconception is that lower turn motors are faster.... when geared properly on a closed coarse they are not any faster, however they are quicker.

Meaning you will have neglegable top speed, however the car will accelerate to that top speed in less time.....


On a tight coarse a good 19t or even stock can hang with a low turn mod... however alot has to do with the driver, car, set-up, track conditions, and if it is on a Tuesday or Wensday........

highwayman

iTrader: (2)

Gotta agree... on a really tight course, a 19T might actually be better, we use to run on an indoor carpet track, which was really TIGHT. for mod motors, i prefer 9x2 motors, 10x2 for staduim trucks... and the reedy for 19T.

DynoMoHum

From what I have seen... the lower the turn the motor is, the more effcienct the motor is, and therefore the more power it makes per given amount of input. I'm sure there is a point where it deson't work out exactly like that, but I'm very confident that a 12 turn motor should put out ALOT more power then a 19 turn motor. You should have both more acceleration and top speed if you've got it geared right.

The more power available to you, the more driving skill you need to control it... More power does not always mean faster laps, but that's primarly due to the lack of driving skill and/or lack of traction...

IMPACTPLAYR

iTrader: (7)

theiretically you are corect, however remember as you drop the turns you reduce the torque, yet increase the RPM.....

the extra top speed is negligable due to the shorter roll-out you use with a low turn mod....

jsp

DynoMoHum: The lower the number of turns the more INEFFICIENT the motor becomes except at very high amps. A 12 turn motor may make more power but it takes more amps from the battery, i.e. less run time. As the winds go down, the rpm increases and the torque decreases, but you gear lower and the amps go up. The effective torque to wheels goes up. That's why a lower turn motor usually accellerates quicker.
john

DynoMoHum

Based on dyno data, a 12 turn is more efficent then a 19 turn across a significant portion of the operating range of the motors.

WIth today's batteries, you don't typicaly dump with a 19 turn motor. So you still could stand to consume a bit more power from the batteries during a race. So being a little less efficnt at the highes RPM is not going to be much a issue under typical race condtions these days.

Power is what is needed to go faster. The more power you have availble the faster you can go.

Power is for all intents and purposes RPM * Torque. If you've got more power output from a motor, you will go faster if you find away to get it to the track. Gears take care of differances in RPM and/or Torque between the differnt wind motors. If the motor has more power output... it will go faster when you put it in a car, unless you mised on the gearing, or your driving is holding you back.

jsp

What rpm ranges and amp loads?
john

DynoMoHum

It really depends on the motor, timing, etc... I don't have all that much data for 12 turn motors, so it's hard to say definitvely...

One thing is for sure a 12 turn will put out more power then a 19 turn pretty much across the entire RPM range.

I'll try to give some examples in the next day or so. Right now, I've got to get some other files off of another computer before I can put anyting up on the internt that would be helpfull in this discussion.

jsp

I have tested several 19t spec motors with 80-83% efficiency in the 20-25 amp range. A 12t in the same amp range is rarely up to 78%. A 12t usually peaks (efficiency) at 30-35 amps at about 80%. A 19t efficiency starts dropping at about 30 amps. The conclusion is at high amps (above 30 amps) the 12t clearly makes more power. BUT the 19t is clearly more efficient.
john

DynoMoHum

Take a look at this graph, it's from Robitronic's Promaster software, it' represents a 12 turn motor (the data in solid lines) and a 19 Turn Chameleon 2 (the data in the dashed lines) THe graph is 'normailised' for RPM... that is the data on the graph is in relation to percentage of maximum RPM. This pretty much show you what things would look like if the motors were geared effectively.


http://www.wiltse.net/images/19v12.gif

At this time that's the best example I can give... I'll try and get more over the next few days.

jsp

Looking at your graph (or whoever's), from 45% to 75% of max RPM the 19t's efficiency is above the 12t. For the 19t motor, that is from 50a down to about 20 amps. Peak power for the 19t is at 50.4 amps and 5.5 volts. The 12t max power is at 65.6 amps and 4.9 volts.
john

DynoMoHum

Yeah, it looks like your looking at the same graph... and from 0% to 100% of max RPM the 12 turn puts out more power.

Here is another 12 turn that is slighly more effcienct from 20 to 50 amps.

FIrst in relation to Percent max RPM (looks pretty much like the other graph of the ohter 12 turn.

http://www.wiltse.net/images/12v19pr.gif


and one you might find more interesting if your concerned about effciency over some specific amp rage...

http://www.wiltse.net/images/12v19a.gif


Those 12 turns are not my motors, they are actualy demo data that comes with the Promaster software. The Chameleon 2 is mine, and is about as good as I can get it to run. I'm actualy fairly confidient that I could get a 12 turn to run more effcienctly then the ones in these graphs.... even the way they are, I beleive the 12 turn motors in either of these graphs would have better acceleration and better top speed then the 19 turn shown here.

jsp

In the first and second examples, the 19t makes more power at the same amperage as the 12t from about 20 to 50 amps. On a Turbo Dyno the cross over point would be ccloser to 30 amps +/-. Below this point, the the 19t has more power. Above this point the 12t has more power. Clearly the 12t does not have more power from 0% to 100%. The 19t has the advantage from 45% to 75%.
john