Academy SB V2 PRO Motor question

[BL_RV0]

would the neu 1509 1y/s on 3s or 4s be good for that buggy? and what esc could i use for ~100-150? lmk! since its a y wind, i think it should work decently with the mm with few cogging issues. what do u think?

[steveo]

how fast do you want to go, as i dont know the wind of the motor but a high rpm motor on 3 or 4s is crazy in a buggy, if you are bashing its ok but you could never race with that setup, if you race, and thats a nice buggy i've been looking at them

[DrKnow65]

So glad to see someone else is going to run this car. I just got maine early this week and as soon as my 3S 5000HV shows up I'll be running it.

I have a Mamba Max, 5700KV, Futaba 3PM2.4ghz, CC BEC and a cellshield lipo protector I'm putting into it. I was looking at the 1509/1.5Y to run on either 3S or 4S depending on if I'm at the track or bashing.

I think the 1509/1Y might be a little fast, but there is a trick for getting the gearing down using ZX5 pinion gears in the diffs with the OEM academy ring gears.

[crazyjr]

I think thats too much for the V2, I'm running a 7700 MM with 2s lipo and had to re-set the slipper because i melted the rear diff

[DrKnow65]

I think the 5700KV on 3S will definatly be too much. The lower KV motor is a must. But I am going to give it a go with the 5700KV before I get another motor.

I'm thinking that slipper adjustment is going to be a big deal. I'm planning on having diff issues too and I've already got the steel outdrives, new rings, and carbon steel 3/32" diff balls on order.

I was thinking I might try a NEU 1506/3Y or mabey even an 1115/1.5Y (380 size) to lighten up the elecronics side of the chassis so I woulnd't have to run a heavy lipo or add weight to balance it out. Run it with a small 2500Mah EVO25 4S, or a MaxAmps 3000HV 4S. Then I could move around components to perfect the weight displacement?

[BL_RV0]

how about a mm 4600 on 4s?

[DrKnow65]

4600kv x 14.8v= 68,800RPM that's only 18,800 higher than the 50,000rpm the motor max. Would make a cool speed run for a few seconds :)

1506/3Y is 1700KV, 1700KV x 14.8v(4S)= 25,160RPM or 1700 x 22.2v(6S)= 37,740RPM

Actually thats only 1200 below the 70k rpm limit that castle recommends, and it lasts more than a few seconds (its probably the most reliable setup I currently own).

[BL_RV0]

so you would recommend it, b15?

[lincpimp]

Personally I would not recommend a mm motor to anyone running a 4wd vehicle, unless it is an 18t! I would say to step up to a feigao s can motor. The have the same construction, but the s cam feigao has a longer rotor, so more torque. I have tried every mm motor now and I have sold them all! For 3s lipo a 12s or 10s motor would be good, you may get by with a 12s on 4s lipo but the rpms (and power) may be too much!

[DrKnow65]

70,000 rpm? I just went back and read the Mamba Max tuning guide and it looks like 60K rpm is the max they want you to run. The 50K I was stating was what I read the bearings were good for. The ceramic bearings I replaced mine with are good to 80K and I havn't found anything higher rated.

How would you gear 70K for a short track? Wouldn't it be easier to gear up a 25-38K motor? I'm also thinking that the 4-pole Neu type motors are more efficient at around 35K?

I don't mean to be an opposing force here :) but I do want a complete understanding...

The reason why I'm concerned is that when I got my MM/5700KV second hand the bearings were trashed and the guy was only running it on 3S (63,270rpm).

[lincpimp]

The 70k rpm limit may be mechanically possible, but the motor will run hot due to lower effecientcy. I am sure that the mm motors run fine at 40k rpm and lower, but lack the torque to get a heavier vehicle moving. It is much better to gear up a slower turning ,more torquey motor, than gearing down a tiny, high rpm motor.

[DrKnow65]

Is there a "rule of thumb" for where a given motor is most efficient?

I was under the impression that 2-pole motors were good at a higher RPM (50K) and 4-pole motors were best around 35K, 6-pole, 8-pole, 16 pole outrunners, ect...

[lincpimp]

I guess it has to do with load and motor construction. The higher end motors, neu, lehner, etc. seem to be able to handle higher rpm without a large loss in effecientcy. However if you atre looking to do high speed runs using tall gearing it will load the motor more. Using a motor that is too small for an specif application and revving the snot out of it to make power will not result well. From what I have experienced, keep the lower cost 540 size motors under 40k rpm and they will be fine. the 380 size motors can handle more rpm, but not more than 50k, and stay with light weight vehicle, 2wd preferably.

BL-Revo, I would reccomend it for a touring car or maybe a 2wd buggy, but I would bet your 4wd buggy would be too heavy. Maybe if youre only using it onroad it would be ok. Mine never thermals, but it does run hot, even with a fans on the motor and esc (140-150 on both). Not to mention it makes more power than you could ever use off road. Really it makes more power than should ever be in a touring car, my TC3 is running a lola body and a handmade lexan underbody/ front splitter/ rear diffuser just to try to keep it on the ground. It will spin all 4 31mm foams with no effort at all.
As for the motor rpm limits, I dont know enough about this to comment on the efficiency of my set up, but someone who works for castle posted on another forum that the mamba 4600 system was perfectly capable of running 4s lipo, that it would be within the rpm limits of the motor. The only problem is the esc wouldnt be warrantied.
I think there is a lot of middle ground between what is most efficient and what a motor can physically handle. Ive run my mini t with a mamba 6800 on 5s lipo, and it works fine, it didnt even need a fan on the quark 33 while geared for about 60. Thats 119k max motor rpm. I know, I dont expect that to last very long. When I replace it Ill probably aim for about 1/2 the kv it has now.