brushless losi 8b
 

hi guys, i have done quite a bit of searching on converting a losi buggy and was wondering what your thoughts were on this setup:
mamba monster 2200kv combo
Rc-M motor plate
6s lipos (i was looking at the flightmax 5000mah 30C lipos???)

basically what i want to know is if this is any good for bashing. i won't be racing but want something that will be able to cope with a high voltage out of the box rather than upgrading the revo :whistle:

what sort of gearing would i need? i am after the longeset run time and about 40mph top speed maybe?

thanks for looking

richard

I have an 8B running on 6S, but I use it for track only. Your set-up seems fine for bashing but I am thinking 5S would probably be enough. I run 6S with my MMM and use a Neu 1512 2Y which is a 1400kv motor and that puts my RPM just below 35k. I geared it at 14/48 to get her to around 40 mph and stock out of the box is 13/48. That's why I think you should be at your goal speed with 5S. I only use Zippy's and Rhino packs for now as they have held up nicely. The flightmax are Zippy batts too so I think you will be happy with them. Hope that helps some.

I think that 6s on that motor is a bit much...put it this way, if it were my choice in motors, I'd go for a 1700 60 series medusa on 5s in a buggy....even lower kv for 6s and just gear up a bit to desired speeds

thanks for the replies
i always thought that the higher the voltage the better because it keeps the electrics cooler?
if i was to run 6s what sort KV motor should i use? will the 1700kv motor not be slightly over the 35K RPM figure?
how many runs have you had out of your zippy lipos? because my trakpowers packed up after about 60 :lol:

6s and a 1515 is way to much for a buggy - the weight of a 6s 5k pack is too much and will impact handling even if you find a way of getting a pack that size under the body.

You are better off with 4s 5k with the mmm and either the 2200 or the 2650. Either will work fine.

Agreed. a 1515 is definitely excessive for a buggy. And 6s 5000mah is going to be super heavy (nearly 1.5 pounds). You'll have the heaviest buggy on earth.

If for some reason you really want the 1515 2200kv motor I'd suggest running 5s 4000mah or something to keep weight down. The excessive motor will also cause unnecessary battery drainage resulting in unnecessarily short run times. What seems to be becoming the "standard" is a 1512/2D 2650kv motor on 4s 5000mah pack. That will give you overall acceptable weight and probably 22-23ish minutes of bashing run time (about 16-17 minutes of hard racing)

What you mentioned will work - but you could be notably lighter and more battery efficient with a slightly different setup.

acually the 1y in a buggy never even opens its eyes, you will barely ever break 40 amps with that motor on 4s, and really the 2650 will seem faster in the buggy because of the high kv

running higher voltage will keep the electronics cooler as long as you also run a lower kv motor or lower gearing

ok so 4s sounds good
i have a mamba max esc that i have been running on 4s for quite a while but i just need a motor. what motor would be best? and what sort of runtime would i be looking at with 5K lipos?
i have been looking into gearing also, i have a 16T pinion already but what others would be a good comprimise for speed and runtime?
sorry for all the questions but i want to get it right 1st time round :yipi:

For a motor you want to run a max RPM of around 35-40,000 RPM. On 4s (14.8v) that would be 2364kv. Personally I run a Neu 1512/2D which is 2650kv and on 4s is 39,220 RPM. A little on the high side but I run on a fairly large outdoor track. I also run 16/46 gearing which I believe puts me at about 42mph top speed. I might be off on that though.

I'd probably suggest the new castle creations 2650kv motor.

-Jeff

my buggy is coming tomorrow :yipi:
i will be using a mamba max esc and 9xl motor on 4s until i get a better esc and motor (once the revo has sold)
what pinion should i use? i have a 14T and 12T hardened RCM pinion and a novak 16T pinion (are the novak pinions ok to use on the metal spur?)

thanks richard

Nice!

I would start with the 14t pinion. Turn the timing down and punch control up on the ESC just to start off conservatively. If everything works well for the first few runs make whatever tweaks you want.

Yes the Novak pinions are fine with metal spur gears. Though if you decide to go plastic there's a new option from Losi - LOSA3560, LOSA3561 and LOSA3562. I've been running my plastic one for about a year. My motor came loose when I cased a jump last week and the teeth went a little flat. I was running the 46t kyosho. I just ordered the 45t Losi to replace it. I'll report after some use how it's doing.

-Jeff

it turned up today and wow is it quick :lol:
running the 14T pinion and the tyres are completly bald now after a tarmac run.
the motor got quite hot though :oops:
i see what you guys mean when you say loud :surprised:
also how did you mount the motor mount because it seems that the stock plastic ones are shorter than the alloy one?
i will get a few pictures up in a bit

thanks richard

here it is:
electrics:
spektrum 2.4ghz receiver
ace DS1015 high torque servo
9xl brushless motor
mamba max esc with brushless fan and BEC
2 ftx 7.4v 5000mah lipos
RC-monster heatsink

14/ 49 gearing (i think thats the stock amount of teeth on the spur gear?)
RC-monster motor mount
RC product designs battery tray and esc mount
proline mug shots on hong nor rims

it runs great, the motor is a little hot but the esc was pretty cool by the end
it makes quite a bit of noise however, with the metal on metal contact between the spur and pinion.

with the gearing as it is i reckon it must be hitting mid 30's which is ok for the motor and esc i am using
i will eventually probably get a Mamba monster esc but what motor would be good? i really don't know whether to go with 4s or 5s though. i am looking for a cool setup with quite a bit of runtime
http://i136.photobucket.com/albums/q.../losi8b001.jpg
http://i136.photobucket.com/albums/q.../losi8b007.jpg
http://i136.photobucket.com/albums/q.../losi8b009.jpg
http://i136.photobucket.com/albums/q.../losi8b010.jpg
what do you guys reckon ???
thanks richard

Yeah - that motor is going to run hot. There's pretty much nothing you can do about it. I mean - you can drop the timing down on the mamba max, gear down a little (but it seems low enough as it is), turn on some punch control.. but other than that - it's just gonna be a hot motor.

You should simply upgrade to the mamba monster 2650kv combo. That would be the way to go for 4s. If you end up going 5 or 6s you have other motor options that are either more expensive (neu, plett, etc) or less expensive and not as effecient (feigao, medusa, etc). Personally I would stick with 4S and run the 2650kv with the mamba monster.

Yes - the steel spur is crazy loud. The plastic one is a LOT quieter but still makes a racket. I like running plastic personally. Never had problems with them and they're MUCH quieter.

-Jeff

BL-Revo,

How many mounting screws does the non-ultimate RCPD tray use? I have the RCPD Ultimate for my E8ight, but it is pretty heavy. I'd like to find something lighter, so I tried the RCM tray, but it only covers 2 of the motor mount screws, which I do not think is enough.

Thanks,

do you mean the battery tray? it uses the 4 engine mount screws that's it :)

does anyone know where to buy an adaptor so i can balance charge my 2 2s lipos at the same time? i have a series adaptor for the deans plugs but don't know where/how to make the balance plug?

thanks richard

Hobbycity.com has some adapters that'll allow you to do that. Pretty sure you have to be careful how you hook them up but they should work. I just use 2 balancers :tongue:

i had a look on the website but i can't find any adaptors that do 2 2s's just 2 3s's????

Interesting...I could've sworn they had a good assortment of them last I checked. I looked again and all I could find was the 2x3 one.

i missed the best deal on ebay last night a Neu 2050KV motor went for $99.99 :surprised:
anyway i am still on the lookout for one of these balance lead converters as i have looked all over the hobbycity website and came up with nothing :lol:

right i have had enough with the temperature of the motor :lol:
it is getting too hot for me and the runtimes aren't up to much either
if i was to go for the 2650kv MMM combo would i see quite a big increase in runtime?
also is it ok to run the mamba monster combo on 4s 4000mah 25C lipos like these:
http://cgi.ebay.co.uk/RC-Helicopter-...1%7C240%3A1318
or would i need a battery that could deliver more Amps?
if i was to keep my mamba max and just buy a motor would the temperature of the esc go down because i have gone from a 9xl motor to a more efficient motor?
will 4s be plenty on a 2000kv motor or would i just need to gear it up a bit?

thanks richard

I've never seen that brand of lipo before so I wouldn't trust it. I have a NeuEnergy 5s 3900 mah pack that is good enough to handle the current that the 2650 draws. A 3900 mah 4s pack is 95 USD so i would go with that. I can easily drain my 4s 4100mAh 30c pack in 12 minutes. I basically found that the 2650 is a very versatile motor on 4s (stays fairly cool w/ various gearing) gets a little warm in a tight space on 5s and runs cool and in a wide open space on 5s and is rediculously fast!

i was having a bit of a think and surely the motor should be run cooler in the buggy than my old revo? i used to have the revo geared on 40/16 and the motor was quite hot to the touch but no where near what it is in the buggy
the buggy geared with the stock spur and 16t pinion means the motor gets very hot. i was wondering if there was any binding but all the wheels seem to run smoothly and it free wheels for a long time on road?

what would be the signs for binding ?

Take the motor out and spin the drivetrain. It should continue spinning for several seconds. Buggies can handle more power than MT's just because they are easier to drive fast. It takes about power to push me 7 mph on a scooter than it does to push my 8ight 35 mph, so gearing down is certainly easier on a motor than reducing the same amount of weight ratio wise.

what would a 3300kv motor be like? and is a 1509 too small in the 2700kv version?

Are these motors for your 8B? A 3300kv on 4S would not be difficult to drive in any race application, use a lot of mah, and run hot. If you are using a 1512 sized motor most are using the 2050 on 4S. A few have tried the 1509 in a buggy, but no one is saying it is the best option. If you do go with a 1509 I'd go really low kv (1450) and 6S. This should keep the heat down in a 1509.

i think i am going to get a 2200kv 1515 motor for now :lol: since i will be mainly bashing :whistle:

That will be plenty of power for bashing. My buddy runs that combo in is Losi 8T on 4S and it is very powerfull. It seems to have more punch than my 8B (MMM, Medusa 60x2000, 4S), but my buggy gets better traction and thus jumps a bit farther at the track. That motor in a buggy should be able to be geared pretty tall without heat issues. I'm guessing 45-50mph.

on 4s a 1515/1y (2200kv) has power but it is controlled, in 5s it gets a little out of control and o havn't tried 6s, i can only imagine. For racing i would say 4s, for bashing 5s is my favorite.

Any ideas why my Medusa 36-70-1600kv motor got hot running 5s geared 14/45 in a Losi 8B. It ran awesome on 4s geared 16/45 and cool but wanted to try 5s to get a little more speed. I know the Losi 8ight diff ring and pinions are 40/13, and with that 45 tooth spur is why I think things get hot easy in this buggy.

I was running a NEU 1512/2.5/D/F (2050kv) on 4s but it got hot, over 175, on any gearing combo from 10/45 all they way to 16/45. All the typical things are ok, drivetrain is free, nothing hangs up. The only main difference I seem to notice is the majority of people on here don't run on a track in race conditions. Speed runs in a parking lot are not going to heat up the motor like running on a track will. I've only ever driven it on the track. There's no way I could run the 2650kv motor, would hit 200 in 5 minutes. Maybe my driving style needs work.

Any ideas or suggestion are greatly appreciated. Thanks.

It could be just bad luck or that your not getting enough airflow. On my 8ight I cut some holes in the right mud guard to get more airflow to the motor. I notice that using the breaks really increases the temps a lot. Try being smooth on the throttle and breaks, do not use drag break, and try to maintain as much speed as possible into the turns.

Other things you have to watch out for are bad gear mesh and any loose connections. Either will increase temps fast.

Somethings going on with your setup. I mostly drive at the track and will run up to 15min non-stop race pace. I haven't had my motor over 150F (Medusa 60x2000 4S geared 13/46 or 14/46). I'd check a number of things:
1. All connections - after a run notice if any of the connections or wires are very hot or hotter than other wires. A bad connection will generate heat.
2. Air Flow - I have a number of large holes in the windshield and a few over both the ESC and motor. I also have the intake vents cut open as big as possible.
3. Diff setup - I'm wondering if you need a diff rebuild. If the oil is no longer doing it's job then the wheels will diff-out badly requiring a lot more throttle for a given amount of acceleration.
4. Gear mesh - sounds like you've changed pinions a lot, but maybe you're just running them too tight. There should be a little bit of free play btwn the spur and pinion at all times.
5. Bearings - A bad diff bearing will generate a lot of heat quick and bad hub bearings can to the same.

Check those and let us know what you find out.

The track was requiring alot of braking, I will definitly check heat on individual wires and connections. Mesh is good, diffs are fresh, I'm using the 8ight-E body so airflow isn't a problem. Bearings all check out. Can't run now for a week or so as the track is getting a rebuild. I really think I should pitch the Losi motor mount get a RC-M mount so I can get a 48 tooth spur in there. That or put the truggy ring and pinions on the diffs (43/10). The Losi motor mount makes changing pinions so easy though, I could try making a way to shim up the diff with with some aluminum plate I have laying around.

Really the temp, speed and handling are good on 4s, but this goes against everything everybody says. On 4s the motor rpm are 23,680, everything says to be between 31,000 and 35,000. On 5s rpm are 29,600 and the temps go up, geared down.

Only other question I can think of is. Are brushless motors super sensitive to undergearing, more sensitive to undergearing than overgearing? I know brushed motors are sensitive to overgearing, just wondering if brushless is the reverse?

Thanks again.

Ive noticed no increase in temps on my motor/esc when i when from 4s to 5s, this is on a 2200kv motor and MMM esc. If anything the esc and motor seem to run cooler..

The basic rule of thumb I've always been told is:
Hot motor + cool esc/batteries = under geared. (not enough load on motor, so it over revs)
Cool motor + hot esc/batteries = over geared. (too much load on esc to supply amps, causes it to heat up & thermal/fail)

Maybe you are just geared too low for the average speed of your track.

Once the track is back up I will do some more testing. I still think I should get a 48 tooth spur in there. What gets me is Losi keeps making the spurs smaller. 45, 44, 43. :neutral:

I believe the Losi spurs are for the Losi conversion kit. Their kit does not raise the center diff up to clear a 48. Which conversion kit do you have? I like the Kyosho plastic spur 46T that RCM sells.

I have the Losi motor mount, mainly because it makes changing pinions and setting mesh so easy but it's actually verry limiting. Probably get a RC-M mount next week so I can get a 48 tooth on there. Although I guess the setup is actually pretty good on 4s. Good speed and very contollable on the track. Guess I just can't stop tweaking. :mdr: