Choice Of Motor For Brushless Jato

Hello, i'am to convert my Jato 3.3 into brushless, and i don't know which motor to take.
I've my ESC and my batteries, it's a Mamba Max controller and MaxAmps 6000HV 14.8 volts, yes, 4 cells!!!

Now i hesitate for the motor choice.

I look for the Feigao 540 8L ( the purple one on the RcMonster store) or a Feigao 380 9L.
I have a lot of 5mm pinion gear, so the 540 with 5mm shaft is a plus for me, but if you think that an other motor will be better for this conversion, tell me please.
I'am not stick on the Feigao motor, but this is the brand that i know better because i have a 540 8XL in my Hot Bodies LSP electric truggy.
I think that Lehner is good motor too but don't know anything about it.

Could you help me please, i want a nitro killer machine.

Thank

David

[BP-Revo]

I'd just go with a Castle Creations Mamba Max 4600 motor. On 4S it will be rocket fast.

On 2S with the same motor, Brian G's Jato has gone 45+ mph I beleive, so on 4S it should be ballistic and easily push 65+mph

However, if you want to go totally off the wall...a 1930 or 1940 will probably get you 80mph at a miminum.

But the 4600 on 14.8 volts give 68080 rpm:035:
I've read on a forum that brushless notor can't spin more than 40000 rpm !!!!!

The Feigao 10L turn 2458 rpm/volt, they give about 36378rpm on 14.8 volts, maybee this setup will last litle more time than the CC 4600:026:

And i've an other question about the Jato drivetrain, how it'll hold all this brushless power ???

[crazyjr]

The 40,000rpm limit is how high most are recomended, the upper limits are usually around 60 to 65,000. It is generally agreed that 40,000 is the upper limit for highest efficiency and cooler running, for everything involved

OK thank you, so i'll stick with Feigao.
I'll try the 540 8L, but any idea on the tranny life.
I've the single speed conversion, because one of my friend have a brushless jato with a Feigao 380 6L on 2s li-po and each time that trany shift into second speed, the second gear exploded.

[BP-Revo]

The CC motors are rated up to 65000RPM. Also, if I'm not mistaken, they give KV in unloaded value, so loaded value will be more around 40,000 anyway.

Also, someone has run a 7700 on 3S before...which yeilds a heck of alot more RPM than 68000 and he has had no issues. 3000 over isn't going to kill it...

Ok but somebody can tell me about the Jato tranny ???
Is this tough enough to handle 4s and 540 8L motor :026:

[BP-Revo]

Yea it should be fine. It will loose traction before anything really...

[jnev]

If it can handle the demands of the 3.3 engine, it should do fine with brushless since mny guess is that it will be getting around the same amount of power, depending on the motor.

I think you would be more than happy with the 4600 on 4s. I run the same set up in my rustler, and I can only describe it as ballistic. The higher Kv works fine because the batteries dont actually put out 14.8 volts under load, its more like 14 volts. So the max rpm comes out to 64400, below the 65k limit. And thats assuming the Kv value is accurate under load, which as was previously stated, probably isnt. I dont mean to say the 8L wouldnt work, Im sure it would be a cool running torque monster, but I think you might be happier with the 4600s speed. Heres a video of my rustler that might help you decide. This is with a 9.815:1 overall gear ratio and stock jato 3.3 tires. I would guess the weight is pretty similar to your jato. I could definitely gear up to go faster, but it hit 55.7 mph on the gps as it is.

[BrianG]

The tranny and diff is pretty tough considering it wasn't designed for the instant torque of brushless. My Jato was clocked at 47mph (2s on the 4600 motor). 60mph is easily attainable on 3s and still within the "rpm limits" of the motor. If you want motor braking and/or reverse, you'll need the single speed conversion (or lock second gear to the clutch). If you still want the two speed, then you'll need to retain the mechanical brake and you won't have reverse. I went with the single speed conversion and it is holding up fine - still plenty of torque to launch the truck while being able to get high speed. All with keeping motor and ESC temps at a reasonable level (<130*F).

[Scoob]

I don't think the 540 L is a bad idea.

The difference would be that the Mamba size motor(really just a 380s internally) pushing your Jato at 50+ would be doing about all it can do. The much larger 540 L would be just bumping along in it's normal range for efficiency without being near it's limits for power output. I'd think you could run a lot longer without overheating.

[BrianG]

I don't know about that. I get almost 50mph on only 2s and it doesn't even break a sweat (both ESC and motor temps are lukewarm at worst). On 3s, it should easily get to ~60mph.

[Finnster]

I would listen to Brian on this, as he's worked thru the conversion, and plans out his projects very well. My biggest concern about the 540L motor would be the tremendous Tq you are gonig to be generating. Realize that a 8L on 4s is powerful enough to heave a Maxx to over 40 mph. They are just generally not used as they run too hot in such a large vehicle. Putting this in a car 1/4 the weight.... :024:

If your friend is detonating his tranny w/ a 380-L on 2S, I would not trust a larger motor on 4S. Plus, that much Tq may make the car near undrivable. I can't imagine a 2 spd would be neccesary anyway.

For all ease, I would prob go with a 4600 from castle. They designed/recommend that motor to work with that voltage. I think the 40K rpm "rule" is more applicable to larger MT sized vehicles bc of the heat issues. On such a light car I would work more within the max RPM limit. Also, since you are running a high volt setup, you will get huge amounts of power w/o drawing huge amps, which is what creates alot of heat.

Its my prediction that the 40K rule will become less important when truely hi voltage (like 8s) controllers for 1/8 scales really start coming out. The gains in eff and drop in amp draw should more than make up for any increased mech friction/heat. Obviously this applies to motors w/ a 65K rpm limit like Neus, LMTs. A Neu running 60K rpm on 8 or 10S will not be outlandish.

Thank you for all your repply. But i'll wait little time before order a new motor.
To the place, i'll try my Feigao 540C 8XL that i've on my LSP conversion and put it in this Jato and gear it with a 26 pinion, and change the original tires for the moab, they have 1 inch more on total diameter than standard 2.2 stadium truck tire.

So considering that the rpm/volt of the 8XL is about 2083, on 14.8 volt, with the single speed convertion, gear 54/26, and with the extra inches tires balloning, i would hit about 60m/h + if i put all this number on the r/c calculator.