1/8th scale......huge motor and huge pinion?
02-23-2013, 02:43 PM
#1
1/8th scale......huge motor and huge pinion?
Guys.....I have a couple questions about motor and gearing questions on the 1/8th scale buggies. I drive at a smaller to maybe medium sized track ( kinda small for 1/8th...but it works.)
I have some local guys , including the guy who owns and operates the track....which seem to think they "have to" or "should run" something like a 2650kv motor with big pinions. Their theory is to just tone it down on the radio and then turn the power back up on the larger tracks.
This goes against things I have learned over the years. I run a Reedy 2100kv with a 15t pinion on my Mugen....it's it's smokin' fast. I know my buggy runs something like a final gear ratio of 3.8 , but some other buggies like an Associtaed RC8 runs like a 4.3. But does that sound right on having some dudes running stuff that big?
So it works on smaller and larger tracks?
Isn't running a big motor , with a big pinion....and then turning it down on the radio.....don't you lose some of the "resolution" on the power curve by doing this? Shorten run times? Hotter electronics?
Can you guys list some advantages and disadvantages of doing it this way? I come from a nitro back ground....where we tuned the motor and gearing to the specific track and track conditions. What's changed?
Would really appreciate some info / advice here.
BTW....I have mentioned that I have read threads on here with guys running 1900kv motors with like 16t pinions.....on 150' long strait away type tracks. They pretty much said I was crazy.
I have some local guys , including the guy who owns and operates the track....which seem to think they "have to" or "should run" something like a 2650kv motor with big pinions. Their theory is to just tone it down on the radio and then turn the power back up on the larger tracks.
This goes against things I have learned over the years. I run a Reedy 2100kv with a 15t pinion on my Mugen....it's it's smokin' fast. I know my buggy runs something like a final gear ratio of 3.8 , but some other buggies like an Associtaed RC8 runs like a 4.3. But does that sound right on having some dudes running stuff that big?
So it works on smaller and larger tracks?
Isn't running a big motor , with a big pinion....and then turning it down on the radio.....don't you lose some of the "resolution" on the power curve by doing this? Shorten run times? Hotter electronics?
Can you guys list some advantages and disadvantages of doing it this way? I come from a nitro back ground....where we tuned the motor and gearing to the specific track and track conditions. What's changed?
Would really appreciate some info / advice here.
BTW....I have mentioned that I have read threads on here with guys running 1900kv motors with like 16t pinions.....on 150' long strait away type tracks. They pretty much said I was crazy.
02-23-2013, 02:46 PM
#2
BTW.........I had over heard someone else at the track that running their 1/8th scale buggy motors.......was to gear it so you run up towards 180 degrees on the motor....so it hits the sweet spot?
I was like "what?"..........you guys notice any difference on how your motor runs between 100 degrees to 180 degrees?
I was like "what?"..........you guys notice any difference on how your motor runs between 100 degrees to 180 degrees?
02-23-2013, 06:39 PM
#3
It makes no sense to me at all to invest in the 2650kv motor at all for racing. It's inherently inefficient. If you have to gear up like that and adjust the radio to that extent, then you've got the wrong motor. If you already are stuck with that motor, then I guess you gotta to do what you gotta do. If you have a choice, then forget about it. You would be much better off with a 1700kv.
A 180 degrees is too hot. That's the redline for most motors. I've only gotten a motor that hot when it wasn't geared properly. About 140 is probably closer to a "sweet spot".
A 180 degrees is too hot. That's the redline for most motors. I've only gotten a motor that hot when it wasn't geared properly. About 140 is probably closer to a "sweet spot".
02-23-2013, 06:55 PM
#4
I usually shoot for 150-160 on motor temps after a 10 minute main. I would also say the most popular 1/8th scale buggy motor is the 1900kv T8.
02-23-2013, 11:15 PM
#5
Was hoping for some people to chime in with the positives and negatives of running smaller and larger KV motors.
02-24-2013, 01:47 AM
#7
Tech Regular
And this is what I have read from many a drivers on this board. From their point of view......why would companies even make 1700 , 1800 , 1900kv motors.....if a 2650kv motor , turned down on the radio does everything?
Was hoping for some people to chime in with the positives and negatives of running smaller and larger KV motors.
Was hoping for some people to chime in with the positives and negatives of running smaller and larger KV motors.
Too hot, too uncontrollable, too much Amp draw -> too hard for batteries + short runtimes
Around 1800-2000kv on 4S is much better IMO. Just gear it to suit your needs. Decent runtimes, and good battery life.
Personally I prefer 1400kv on 6S: low temps, low Amp draw, long runtimes, controllable and more power than you'll ever need
02-24-2013, 04:34 AM
#8
I do my fastest laps with a 1400kv 5s and I tried almost everything from 4000kv in 2s to 1350kv in 6S, running 2S, 3S, 4S, 5S, 6S in my 1/8 buggies
Best temps and runtimes are reached with a 1400kv 6s setup but it's a bit too powerful for my taste, 1400kv in 5s is just perfect. The funny thing is I've never seen this setup in another buggy, but to me it's the best overall.
if you need to go 4s because of the stupid roar rule choose a 1700 or a 1900 t8
Oh and I forgot: you can't compare a turned down 2650kv with a low kv motor. Try it yourself, check your laptimes, runtimes, temps. If you could get the same feeling and performance with a high kv motor compared to a low kv no one would sell the low kv.. I'm still waiting for a +/- 1200kv sensored motor to be released to run it with 6 cells, that would be ideal
Best temps and runtimes are reached with a 1400kv 6s setup but it's a bit too powerful for my taste, 1400kv in 5s is just perfect. The funny thing is I've never seen this setup in another buggy, but to me it's the best overall.
if you need to go 4s because of the stupid roar rule choose a 1700 or a 1900 t8
Oh and I forgot: you can't compare a turned down 2650kv with a low kv motor. Try it yourself, check your laptimes, runtimes, temps. If you could get the same feeling and performance with a high kv motor compared to a low kv no one would sell the low kv.. I'm still waiting for a +/- 1200kv sensored motor to be released to run it with 6 cells, that would be ideal
02-24-2013, 06:05 AM
#9
Suspended
iTrader: (7)
The guys at your track have absolutely no idea what they are talking about.
1. A setup like that is much harder on electronics. It is really hard on the esc to never reach full throttle, as the ripple current get built up from not going full throttle.
2. Anything more than 155° and you are starting to run the risk of damaging the motor. Magnets do not like heat, and a bit past the 155° the heat will start to demagnetize the rotor. The 155° rule should really only be your target with a spec motor (like a 17.5) where you need to gear it as tall as possible to get every bit of performance out of the motor to be competitive. With something like electric 1/8 scale (or any mod 1/10 scale class) you can run a motor and gearing that makes all the power you need without having to push the temperature envelope. If you need more power than you can gain by changing the gearing, then you can just go to a bigger motor.
3. If the high KV turned down argument was true, you would see the pro drivers doing it in all forms of electric racing. Have you heard of any pro running a 2.5 turn motor in their 2wd buggy? In open electric racing you can have a setup where the motor makes all the power you need, doesn't make a lot of heat, and can still hit full throttle. If you race on a tiny indoor track in the winter, and a massive outdoor track in the summer, then you would probably do best to have two motors, but otherwise a 1900kv with the right gearing should work perfect for just about any track.
It sounds like the guys you are arguing with have no clue what they are talking about. The best bet for you is to just sit back and say nothing. Laugh to yourself about it, especially when their stuff lets out the magic smoke, or they break their car because they can't control all the power they are running. As the old saying goes, "if you argue with a stupid person, all they will do is drag you down to their level, and beat you with experience." Even if you show them pro driver setup sheets they will just say "oh they were really running a different motor." Or, if you show them a picture of a pros car they will say "oh the manufacture made them a special motor that said 1900kv, but it really is a 2650kv." Remember the other saying. "The difference between intelligence and stupidity is that stupidity has no limit." You seem like the type of person that hears the stove is hot, don't touch it, and listens. These guys seem like the hands on type if you catch my drift.
1. A setup like that is much harder on electronics. It is really hard on the esc to never reach full throttle, as the ripple current get built up from not going full throttle.
2. Anything more than 155° and you are starting to run the risk of damaging the motor. Magnets do not like heat, and a bit past the 155° the heat will start to demagnetize the rotor. The 155° rule should really only be your target with a spec motor (like a 17.5) where you need to gear it as tall as possible to get every bit of performance out of the motor to be competitive. With something like electric 1/8 scale (or any mod 1/10 scale class) you can run a motor and gearing that makes all the power you need without having to push the temperature envelope. If you need more power than you can gain by changing the gearing, then you can just go to a bigger motor.
3. If the high KV turned down argument was true, you would see the pro drivers doing it in all forms of electric racing. Have you heard of any pro running a 2.5 turn motor in their 2wd buggy? In open electric racing you can have a setup where the motor makes all the power you need, doesn't make a lot of heat, and can still hit full throttle. If you race on a tiny indoor track in the winter, and a massive outdoor track in the summer, then you would probably do best to have two motors, but otherwise a 1900kv with the right gearing should work perfect for just about any track.
It sounds like the guys you are arguing with have no clue what they are talking about. The best bet for you is to just sit back and say nothing. Laugh to yourself about it, especially when their stuff lets out the magic smoke, or they break their car because they can't control all the power they are running. As the old saying goes, "if you argue with a stupid person, all they will do is drag you down to their level, and beat you with experience." Even if you show them pro driver setup sheets they will just say "oh they were really running a different motor." Or, if you show them a picture of a pros car they will say "oh the manufacture made them a special motor that said 1900kv, but it really is a 2650kv." Remember the other saying. "The difference between intelligence and stupidity is that stupidity has no limit." You seem like the type of person that hears the stove is hot, don't touch it, and listens. These guys seem like the hands on type if you catch my drift.
02-24-2013, 10:06 AM
#10
Awesome replies you guys....and thanks! I wanted to hear from some experienced drivers about this stuff.....because honestly , after being out of the driving thing for a good 7-8yrs , and being new to the electric stuff.....I didn't have much knowledge to throw out a logical debate.
I tried to explain to a few of them that guys were running 1900kv motors on tracks with 150' long straits.....and basically they keep telling me I'm crazy. That is about twice as big as the track we run on. I'm running a Reedy 2100kv with a little 15T pinion.....and the thing is a ballistic missile on that track.
I also tend to try and tune my buggy for each individual track and make adjustments throughout the day on things as the track changes. A few guys there.....will run the same motor and pinion on that little track......go to a larger one and then just turn the radio and ESC up for more power.
To me.....that didn't seem right. And I knew there were reasons why most people don't do it....I just wasn't sure what those reasons were.
I tried to explain to a few of them that guys were running 1900kv motors on tracks with 150' long straits.....and basically they keep telling me I'm crazy. That is about twice as big as the track we run on. I'm running a Reedy 2100kv with a little 15T pinion.....and the thing is a ballistic missile on that track.
I also tend to try and tune my buggy for each individual track and make adjustments throughout the day on things as the track changes. A few guys there.....will run the same motor and pinion on that little track......go to a larger one and then just turn the radio and ESC up for more power.
To me.....that didn't seem right. And I knew there were reasons why most people don't do it....I just wasn't sure what those reasons were.
02-24-2013, 11:21 AM
#11
The guys at your track have absolutely no idea what they are talking about.
1. A setup like that is much harder on electronics. It is really hard on the esc to never reach full throttle, as the ripple current get built up from not going full throttle.
2. Anything more than 155° and you are starting to run the risk of damaging the motor. Magnets do not like heat, and a bit past the 155° the heat will start to demagnetize the rotor. The 155° rule should really only be your target with a spec motor (like a 17.5) where you need to gear it as tall as possible to get every bit of performance out of the motor to be competitive. With something like electric 1/8 scale (or any mod 1/10 scale class) you can run a motor and gearing that makes all the power you need without having to push the temperature envelope. If you need more power than you can gain by changing the gearing, then you can just go to a bigger motor.
3. If the high KV turned down argument was true, you would see the pro drivers doing it in all forms of electric racing. Have you heard of any pro running a 2.5 turn motor in their 2wd buggy? In open electric racing you can have a setup where the motor makes all the power you need, doesn't make a lot of heat, and can still hit full throttle. If you race on a tiny indoor track in the winter, and a massive outdoor track in the summer, then you would probably do best to have two motors, but otherwise a 1900kv with the right gearing should work perfect for just about any track.
It sounds like the guys you are arguing with have no clue what they are talking about. The best bet for you is to just sit back and say nothing. Laugh to yourself about it, especially when their stuff lets out the magic smoke, or they break their car because they can't control all the power they are running. As the old saying goes, "if you argue with a stupid person, all they will do is drag you down to their level, and beat you with experience." Even if you show them pro driver setup sheets they will just say "oh they were really running a different motor." Or, if you show them a picture of a pros car they will say "oh the manufacture made them a special motor that said 1900kv, but it really is a 2650kv." Remember the other saying. "The difference between intelligence and stupidity is that stupidity has no limit." You seem like the type of person that hears the stove is hot, don't touch it, and listens. These guys seem like the hands on type if you catch my drift.
1. A setup like that is much harder on electronics. It is really hard on the esc to never reach full throttle, as the ripple current get built up from not going full throttle.
2. Anything more than 155° and you are starting to run the risk of damaging the motor. Magnets do not like heat, and a bit past the 155° the heat will start to demagnetize the rotor. The 155° rule should really only be your target with a spec motor (like a 17.5) where you need to gear it as tall as possible to get every bit of performance out of the motor to be competitive. With something like electric 1/8 scale (or any mod 1/10 scale class) you can run a motor and gearing that makes all the power you need without having to push the temperature envelope. If you need more power than you can gain by changing the gearing, then you can just go to a bigger motor.
3. If the high KV turned down argument was true, you would see the pro drivers doing it in all forms of electric racing. Have you heard of any pro running a 2.5 turn motor in their 2wd buggy? In open electric racing you can have a setup where the motor makes all the power you need, doesn't make a lot of heat, and can still hit full throttle. If you race on a tiny indoor track in the winter, and a massive outdoor track in the summer, then you would probably do best to have two motors, but otherwise a 1900kv with the right gearing should work perfect for just about any track.
It sounds like the guys you are arguing with have no clue what they are talking about. The best bet for you is to just sit back and say nothing. Laugh to yourself about it, especially when their stuff lets out the magic smoke, or they break their car because they can't control all the power they are running. As the old saying goes, "if you argue with a stupid person, all they will do is drag you down to their level, and beat you with experience." Even if you show them pro driver setup sheets they will just say "oh they were really running a different motor." Or, if you show them a picture of a pros car they will say "oh the manufacture made them a special motor that said 1900kv, but it really is a 2650kv." Remember the other saying. "The difference between intelligence and stupidity is that stupidity has no limit." You seem like the type of person that hears the stove is hot, don't touch it, and listens. These guys seem like the hands on type if you catch my drift.
The biggest mistake guys make when running 1/8 is overpowering their car. 4s on a 1700 is more than enough for most tracks. And it's a lot more efficient than 2650 and MUCH easier to drive.
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