gearing for 8xl in maxx ? - Page 2 - RC-Monster Forums

speedy · 01.19.2008, 08:50 PM

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$

suicideneil · 01.20.2008, 08:46 AM

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.

speedy · 01.20.2008, 09:05 AM

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 ?

speedy · 01.20.2008, 12:54 PM

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....

suicideneil · 01.20.2008, 01:20 PM

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....

speedy · 01.25.2008, 10:23 AM

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 !

neweuser · 01.25.2008, 10:52 AM

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

speedy · 01.25.2008, 11:12 AM

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

Patrick · 10:31 PM

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.

stum · 01.27.2008, 07:54 PM

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.

speedy · 12:19 PM

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

suicideneil · 01.28.2008, 01:38 PM

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.

nitrorube · 01.28.2008, 01:52 PM

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