gearing for 8xl in maxx ?
 

Hi !

Coud i use a smaller piniongear if i put a feigao 8xl motor in my 3905 emaxx ?
The stock gearing is 19/68 ? i'l run it on 4s lipo !

ARe you running stock diffs? I assume this is 32p gears, if so, you may want a smaller pinion. But i have not ran 32p for sometime. so someone else may want to chime in here.

i was just about to ask that question. my maxx is being converted to BL. it's still stock now but soon i'll be running a 8XL motor, 12 cells, and i'll get 3.3 diffs and all installed! but i have no clue how to gear it.

Use Brians's Speed calculator but you have to change the e-maxx gear ratio as it is different on the new EMAXX...

http://scriptasylum.com/rc_speed/

I believe:

Differential Ratio: 3.307
Transmission Ratio: 1.16

The new tranny ratio is 1.83:1 (stock single speed). The diff ratio is the same as the stock revo or emaxx 3906.

Hi !

Are the neu 1521 size motors to big for a 3905 e-maxx ?

I'd like to have the most effichent bl system possible for max 6s lipos and topspeeds of 40mph ! and bed able to bash hard for 30-40min without overheating the system :intello:

A Neu 1521 will kill your complete drivetrain when you on the throttle the first time. I you like much power, then take a Neu 1515 and if you want a good controllable setup, take a Neu 1512.

1515 1.5y (1500kv) on 6s geared for 40mph should give fairly low amp draw and cool temps.

Are the neu 1512 motors stronger and more effichent than a feigao 8xl ?

The Neu Motors are more efficient than the Feigaos.

They are much more powerful and way more efficient than the 8xl motor.

Neus produce roughly twice the torque of the feigaos (4pole vs 2pole), so you could use a smaller motor like the 1512 and get the same results as using the larger feigao XL motor. Only snagg is price difference, but since you are interested in Neus, I guess you knew that already.

ok:intello:

So if put a neu 1515xxx motor in my e-maxx and run it on the same nuber of lipocells and gearing it will pull alot less amps and manage to get more rpm's to the wheels because of the tq of the neu ? how big difference in ampdraw will it be if i gear a neu with the same kv the same way as my feigao 8xl ? 20% ? less or more ?

By the way is there a better motor alternative than neu's ?

how much more do the Neu's cost?

It will draw slightly fewer amps in theory, but its more about efficiency. The feigaos are cheaply made motors, and waste alot of energy as heat, where-as the Neus are very well made and turn more of that energy into phyiscal power, in terms of wattage (both motors will draw the same current, but the neu will use it more efficiently). As a result you can gear the Neus a fair bit higher, and they will still run fairly cool compared to a feigao treated the same way. RPMs is simply relative to voltage and which motor KV you choose.

1515/1.5Y = 1500kv, good for 6s and the coolest setup.
1515/2.5D = 1700kv, good for 5/6s
1515/1Y = 2200kv, good for 4/5s
1515/1.5D = 2700kv, good for 4s, but the warmest setup.

Depends what you mean by better. There are Lehner motors which are just as good as Neus, but they are 2 pole motors rather than 4pole, which means they will run better on all escs, but they are based in Germany, making them rare to find.

There are also the Plettenberg motors, which are 4 and 6 pole, but they tend to run warmer than the Neus since they have higher KV ratings, and they cost over $300. They are the sexiest looking motors though.

There are the Mega motor motors which are multi-pole inrunners, and they have massive torque, but the case design isnt the best for MT or car use.

And then there are the Align 600XL motors, which are a hybrid outrunner, with an inrunners case design. They are also massively powerful but tend to have a lowish KV rating making them better for high voltage applications, and some escs have trouble starting them, so gearing and programming has to be carefully tuned to avoid cogging.

EDIT: Prices vary, but:

Feigao XL = $60-90
Neu 1515 = $250-300
Pletty = $250-350
Megamotors = $150-200
Align = $150-200

how about those kb.45 motors ? the ones that are 45x63mm and have a 6mm shaft ? 2300kv. aren't that motor more effichent than a 8xl feigao ? it choud have mot tq :) and it's cheap ! 50$

Ah yes. They are similar in design to the feigaos, only a larger diameter and the have a 30mm mounting pattern which uses 4mm screws. You would have to use a modified motor mount to accomodate the motor, but it is possible to grind the shaft down to 5mm with the use of a file and spinning the motor (fix it to bench or in a vice, then run it at low speed whislt working away on the shaft). A couple people have used them, and them seem to produce alot of power- good batteries are a must though.

but woun't they draw less amp's thamn the feigao 8xl motor ? with the same gearing and voltage ? the larger diameter choud give it mor tq ?

if i can hear the motor riving high like all the time and the slipper is tight and the rest of the drive line i fine does that meen that the motor is undergeared ? i use maxamps old 8000mah packs (two 2s8000mah in series ! )
and with the feigao 8xl motor that i use now i got only aboud 20mins runtime is that normal ? i have the new e-maxx and stock tires. even with 22/68 gearing the motor rives high, but i guess that coud because of the lack of traction on the snow. Woud it make a big difference if i get som trakpower 4800mah pack ? they are 200g+ lighter and has a way higer dischargerate....

I ran those number through the calculator, and it says you should be doing about 32mph, which does seem a bit slow for that setup I must admit, so it may well be undergeared. If the motor is hotter than the esc by a long way, then I would suggest going down on the spur and up on the pinion (spurs are cheaper, but there is a limit to how small you can go/find with 32p gears). As for the KB45, I dont know what kind of amp draw they are rated at, so you would need to try and track down some specs or find someone already using them- there are a few on RCM so its just a case of doing a little looking around really. The L can sized version would be similar to the XL feigao I reckon, but the XL sized version should be a good bit stronger in theory, given the same length but a larger diameter & larger magnet.

Batteries however is another thing entirely. If the old maxamps packs really seem to sag under a heavy load, or heat up more than is ideal, then it might be time to upgrade to something higher spec for the more powerful system, and save the old batts for smaller vehicles. I'd look and see what other people run for the best idea, but anything with over 5000mah and 20c is a good bench mark I believe....

woud a 24/54 gearing be ok in my 3905 emaxx with a feigao 8xl motior ? acccording to brians calculator thats only 38mph on 4s lipo !

Is that 32P gears? If so, it might be a tad on the highside.

yes it's 32p gears !v mabe 22/54 or 19/54 woud be better ?

It doesn't matter if it's 32p or mod1, either way it's the same ratio.
What numbers are you using in the calculator? Because I got an estimate of about 44mph with that gearing (11.7:1 fdr) on a feigao 8XL, which I think could be a bit high for normal use.
19/54 should be ok if it fits, but 22/54 would be around what you need to do 40.

I suggest going with a 24t pinion and change your gearing based on temp. You can start stock at 68t which will for sure work, then you can use the 62t, or the Jato spurs that are 54, 56 & 58t. I would bet 24t/58t would be just nice for you.. for avg bashing. Nice speed and decent temps.

choud i be able to hit 40mph with my mm/feigao 8xl setup ? without frying enything ? if i use some punchcontrol and lowest timing.

40 is quite do-able, just make sure you feed the system good batteries, otherwise the speed will soon drop off and the batts WILL cook with cheaper cells. Punch control and lowsest timing should make it easier to handle the truck, from a standstill, and reduce wheelies... in theory.

i just put a mm with feigao 8xl in my new emaxx with a 4cell lipo and it made me quite happy,cant tell you how fast but im thinking 35,wheelies on demand! and im running a rc monster 18 tooth spur,motor got a little hot about 140 so i think i need a 20 or 22 spur,hope that helps,love my emaxx now:yipi: