What bl motor to use with 3s lipos
 

Ok let me try to make this short as possible, at first I was trying to order the VXL rustler, but then decided I did not want to wait 40+ days for it. So I went ahead and order a XL5 Rustler, bearings, carriers, rpm bumper, wheelie bar, Durtax Ice charger, balancer, ir temp gun and other stuff. An now I want to order the brushless motor and lipo. I want to get the Maxamps 3s 8000mah lipo, and the mamba max 5700kv motor, My question is will I be fine with the temps on the motor, with medium bashing? I started to get worried when I read people having heat issues with the 5700 and less volts. I will gear down and get a aluminim tranny case if I must. Or should I go with the mm4600 motor or maybe even a diffrent brand motor like the Feigao 12S with the mamba esc. Thanks for the input, im trying to order the motor before the 6/13th because that is when bpp.com ends the 170 doller presale on there mamba.

The 5700 will work great on 3s lipo, that is that motor's sweet spot. You should gear around 15/86 and you should be all good. Just remember that if you will be running in tall grass or deep sand to drop the pinion a tooth or two or raise the spur to a 90t. I also recommmend you get the aluminum idler gear as well because the stock plastic one will strip in no time.

Pffft! Aluminum idler? Get the steel one! And the FLM steel diff!

Thanks guys, ya I already orderd the alum idler gear with all the stuff I listed above from tower, forgot to mention that. So my temps will be alright, as long as nothing is binding or anything and I gear lower? Cool thanks

Heyitsme I just realised that you double-posted this thread. I replied to the other one too. LOL.

The 5700 is a good motor, and will run well on 3S lipo; however, if you haven't gotten the motor yet, you might also want to consider the 4600. I believe it to be more flexble. You could run it on anything from 2S up to 4S lipo. It goes from being the most sedate Mamba Max system, to the wildest of the lineup.

I think the 5700 is too close to its max at 3s, its still under warranty, but mine heated up too much no matter how i geared it, This was in a T4. I run a 4600 now in the same truck and am happier, I can run 2s and its controlable and 3S is insane

Ya I havnt orderd the motor yet but will tonight for sure. So you think 4600 will be good? what kind or speed can you get off the 4600 and 3s lipo with or around 15 thru 18-86 gearing?

Edit: And how bout with 7 cell nimhs what kind of speed?, I decided Im going to order a 7 cell IB nimh, and Maxamps 3s 6000mah Lipo

And did it seem more controlable on the 4600 motor with the 11.1 volts?

Thanks

If it were me I'd go 4600, the lower KV will make it heat up less and run more efficient. You may not be able to use the 8000 mah 3S as its big BIG, I just got a 5000 maxamps pack in both 2s and 3s. The 8000 2s will fit only a little modification, the 5000 3s will fit perfectand weigh less than a 6 cell pack

Wow what a hard choice, on other forum people telling me I will be disspointed with the speed of the 4600, when I could go with the 5700. An here you guys say its good. I dont know what to do, I got one more day to decide any other opinions would be great, thanks guys so much for the info and help

Edit: I still leaning slightly towards 4600 over 5700, because I really dont want to deal with heat issues that much, But are they any other setups that run similar price or alittle more then mamba, that will take 3s, good speed, and run cooler then mm?

And to whom it concerns Im very sorry for double posting same topic I should of only posted in this forum.

On 3s lipo, the 4600 will hit rpms of around 51,000. That's pretty high. Lower kv motors are more forgiving with gearing too. The 5700 could hit the same speeds, but you'll really have to find the sweet spot gearing-wise to prevent overheating. If you look around here, you'll see a number of examples where it is better to use a lower kv motor with higher voltage.

What other forum is telling you this? Are they brushless "experts" or people that just slap in any old thing and run it hard? Most everyone here will offer solid advice for a reliable setup based on experiences.

I bet its the traxxas forums, they got a nasty case of more's syndrome there. They got people that say a 4600 mamba is almost perfect for a Maxx. The same people say the 3500kv motor in the velineon system is junk, because its slow. Not all of them, there are a few good people with experience, but they are few and easily stomped, by volume

That's too bad. So, people are going to get the wrong info and get a system they won't be happy with and then they will have a bad taste in their mouths for BL tech in general.

This the home of the brushless "experts".

I would have to agree with the 4600 as well. I picked up a 5700, but after a couple runs, I got the 4600 and it runs cooler and is PLENTY fast on 3s.

I wouldn't say its more controlable, when you put that much power through your driveline there is no such thing as control. I will say this, I run my 4600 sunday at my track for play (nobody else had one there) even if i had a mm left to gowhen i pegged it it would wheelie out of control, I did two backflips with the T4 and blew out three tires on the 3S pack

Haha, you are right on, it was the traxxas forums, and there are all still telling me to get the 5700 with 3s lipo, and I was and still am maybe thinking of going with the 5700, and get 1 5ah 2s lipo, and 1 5ah 3s lipo. But when I come to this forum, you guys make me want to get the 4600 and 1 3s 5ah or 6ah lipo battery and 1 7 cell IB nimh. An you guys are right im sure there are alot more people on this forum that know what there talking about and been in the hobby alot longer, including your crazy, and couple you said that you have switched from 5700 to 4600 to run with 3lipos, and you guys wouldnt switch for no reason right?. This is example of what traxxas forum people who run 5700 3s say.

(you can run the 5700 w/ a 2cell if you want and get about the same speed as the 4600 on 3cells, but for that price you can get 2 batteries or just 1 large one of a 2cell for the 5700. I run my 5700 at times w/ a pair of 6000mah 2cell's linked and I get bored way before I run out of juice You can always snag a small 4000mah 3cell for some speed passes high speed runs etc on the asphalt. I think if you gear your car right even w/ the 3cell on the 5700 you shouldn't have to worry much about heat. It's wicked fast so going down to a 12-14t pinion is fine even a 90t spur.)

( not w/ a 4600, get the 5700 hands down you can use the mamba software to control your motor all you want, but w/o a 3cell it's gunna be SLOW, slower than your Titan 12turn or at best the same speed.. why spend that much money if you don't want a little more or the possibility of a little more? A 3cell w/ the 4600 could be decent... but otherwise you can buy an aweful lot of titan 12t replacements if all you want is the performance you get w/ that.)

and another 3s 5700 user said Get the 5700.
thats why im stuck inbetween the two Im getting diffrent anserws on diffrent forums
Thanks so much guys, im going to wait for a few more response and then make the order in the next 5 hours. still dont know whitch one tho, and does anyone have an idea how fast 4600 will go on 7 cell nimh?

If running it on 7 cells, then go with the 5700. If 3s or 10 cells, go with the 4600.

To calculate motor speed, simply multiply the voltage by the motor KV. So, 4600kv * 8.4v = 38,640rpm. The idea is to use the lowest kv motor you can for the voltage you are using. Higher kv motors means more current, which means more losses, which means more heat. Basically, it's better to develop high power with high voltage and lower current than the other way around.

No Im planing on buying one 7 cell nimh, or 2s lipo for control and offroad, (AND one 3s lipo for sure, for high speed), I spent the extra money on the ice charger to charge lipos so im going with 3s no matter what. I just cant decide to what motor to run it on with out having heating issues. Crazy how fast is your 4600 on your 2s lipo setup?

I agree with you on bashing, the 5700 is best on 2s and 6-8 cells. I choose the 4600 because mine will be raced and the 4600 feels better on the track on 2s. The 8000 pack is awsome in my T4 and fits almost perfect (had to move the strap screws up a little) and the pack is lower in weight (by 50 grams) than any 6 cell pack

If you will be running 2s or 7 cell packs for the most part, then yeah the 5700 may be a little more what you want. If you do 3s on the 5700 for speed runs, just watch how hot ya get it. I only run 3s in mine, so the 5700 is ******* crazy, and heats up a lot. The 4600 can run all day on 3s.

I will be running it on 3s lipo and 7 cell nimh or 2s lipo . Im planning to use them equaly after one dies put in the other or what mood im in and what terrain, but I will probley mostly use 3s lipo if I can control it. thats why im trying to get an idea how fast, a 7 cell nimh or 2s lipo goes with 15/86 gearing on the mm4600 motor on a rustler. im hoping at least 30 to 35 mph a good controlable speed for when i dont want crazy. Anyone have an idea on thoese speeds? thanks

3 more hrs to order time. the more feedback the better, still undecided

Even if 3s is too fast, you can always not go WOT you know. ;) Or, cut back on the throttle EPA. This will also help runtime too.

Ya thats true, im think more along the lines of not being able to control it in dirt,or off pavment with it spinning the tires and spinning out with 1/16" movement of my unsteady finger and 11.1 volts. But yes I plan on mostly using 3s lipo, so im still leaning towards 4600, but how long bdebde does your 5700 3s take before it starts getting to hot, with medium to slow bashing speeds?, and more high speed use? thanks guys for your help. After tonight I wont be bugging you guys no more, and hopefully this thread will help others in my situation.


Edit: and whats is EPA?

epa=end point adjustment. It's a setting found on the transmitter that limits the servo travel (or throttle in this case). Some of the more inexpensive radios may not have this setting though.

Medium to slow speed tend to heat up the ESC faster. After 10 - 15 min the 5700 is too hot, and that is about how long the 3800 li/mn batt lasts. I get 15 to 20 min runtime with the 4600, so if you want longer run times, go 4600. I even have a hard time getting the 4600 up to full speed, without a large parking lot.

From what I hear from the traxxas forums, it sounds as if most of those people haven't even tried a mamba max, let alone any brushless system. The 4600 is no doubt faster than the 12 turn titan motors, even on 2s lipo. In fact the 4600 on 3s lipo will blow away the 5700 on 2s lipo. All most anything, really, on 3s lipo is faster than most 2s setups. In fact, I'd expect the 4600 on 3s to be on par with the 7700 on 2s lipo if not faster. I have a feigao 380c 9t, which is similar to the 4600 and the front end of the vehicle (modified xxx4) can start to lift off the ground if you don't watch it, especially on the road surface in front of my house. Actually my 380 12s (3300 kv) on 3s is just slow enough for running right in front of my house (300 foot straights). Unless you run on a track, its not the control you have to worry about (well depending on the vehicle. 4wd is easier to drive). It's really the buckles in the road that can send your vehicle flying if you don't watch it.

Ya I dont know about the traxxas forums, most the people there registerd in 2007. Does anyone think I would be able to gear up a rustler with the 4600mm and 3s lipos to go around 55, with out over heating the setup, for on and off road bashing?

Or should I change my order to 5700 for thoese speeds.

I would say keep the 4600, if you really need more speed then get the 5700 (try gearing up first). I went the other way and got the 5700 first. It was way too fast as well as getting pretty hot, so I had to get the 4600 so I could actually have fun with it.

shouldn't be a problem, I had my T4 on a 5700 at 45 it flipped backwards and skided about 75feet, it took the outer most holes in the shocktower, all four of them. I know it was doing 45 because a friend, was radaring it, I was trying for 60;) need a couple ounces on the front. I think the 4600 could be faster, because you should be able to gear it higher than the 5700.

Are you sure 55 is what you are looking for? What was your previous setup? Most 2wd vehicles can't even reach that speed unless you are running at an airport or a perfectly smooth parking lot and 300 feet of radio range. Otherwise the vehicle will just wheelie unless you carefully guide the trigger to full throttle. And you definately can't reach that speed offroad. Anyhow 55 is doable with the 4600 incase you are still in doubt, but you will have to watch the temperatures as you would with any setup geared for 55.

I am at my sisters this weekend and thought i'd run my T4 3s setup on the dirt road in front of her house, I figured the dirt would let me get to top speed easier with wheelspin (as opposed to blacktop traction). Well same story, even at 7/8 throttle, when i pull full throttle, the front jumps up and the back becomes a dirt scoop. So i need a few ounces in front for top speed runs

cool 2300 posts

I have had bad luck running higher kv motors, too much heat and damage.

Running high kv motors can work provided that the right voltage is used to keep them from over-revving and proper gearing is used to help reduce the motor load a little.

Unfortunately, most people who want high speeds automatically assume they need a high kv motor. Then, they use too much voltage and gear too high creating issues.