9920/8L questions and more

[macfjej]

oodles of questions

1.
how fast would a stock e-maxx (with CVDs) be with 14 GP3300s and a 9920/8L setup.

2.
how is it determined what a "good" number of cells to run on a motor is?

3.
why don't you sell feigao XL motors anymore?

4.
what's the differeance between S,L,XL. it is single, double, and triple winding? what??

5.
how many cells can you run the 9920 bec on until you need a Ubec

6.
is the 9920/8L a good setup on a stock maxx, or would it over strain the motor? ,, basically 8L or 9L? looking for speed over run time,,, and durablilty over speed

7.
what would you need to gear an 8L, 9L system at?

8.
should i get the "S" or "L" size motor heatsink/clamp? since they both fit L.

thanks for the help

[MetalMan]

1. It would go pretty fast, about 45mph, but it would get pretty hot. The best choice for the 8L is 12cells.

2. A good number of cells can be determined by trying to keep the motor's RPM between 40,000-45,000. This is figured by the battery voltage multiplied by the motor's kv rating.

3. The standard Feigao XL motors have been replaced by the Wanderer motors, which have a rated kv with a load (Feigao is unloaded), and also have better bearings than Feigao motors. The color of the Wanderers is blue.

4. The difference between S/L/XL is the length of the motor. S=short, L=Long, XL= Xtra Long. The longer the motor, the more torque it can put out.

5. The 9920's BEC shouldn't be used for more than 12 cells.

6. A 9L will be better, as the 8L will get rather hot.

7. Someone else will know gearing better than I do.

8. The L heatsink/clamp will cover more of the motor, so will dissipate more heat, but it will be slightly heavier.

[squeeforever]

gearing for a 8l on 12 cells would be somewhere around 13/66.

[RC-Monster Mike]

Thanks, metalman and squee! Well answered!

[macfjej]

yeah, thanks! but i'm still going to squeeze a few more answer out of you guys lol!

9.
what speeds would you get out of an 9L (14c)? i think i read one guy say 38mph out of a 9L,,,,not to split hairs but i was hoping to be able to do 40-45 mph on a straight road

10.
will the 8L run still run hot with the heatsink/clamp, if so, what is the 8L used for? (ie. super light maxx)

11.
if you have a 99 amp speed controller, does that mean it pumps 99 amps when your going all out? please explain,, at least a little

12.
if it's best to use 12 cells for an 8L, why does the info say it's for 12-14 cells maxxes? just curious

to add a little info, we're using 12 & 14 cell GP packs, some new, some old

[nbcaznmaster]

9. I think 40-45 is plausable, you just gotta watch the temps on the setup and maybe really lighten up ur maxx
10. 8l would be good for light maxxes
11. Not neccesarly, sometimes theres peaks too.
12. 12-14 cells is teh range. YOu can use 14 cells, but it just isnt a good idea. If you want 14 cellss, get a 9L, its bigger, and beter suited for a heavier e-maxx.

[MetalMan]

9. It would help to get a larger motor (like a XL) if you want higher speeds like that.
11. The 99amp rating just tells you what the controller is capable of delivering to the motor (the motor is the one that pulls current from the controller).

[RC-Monster Mike]

The 8L can run on 14 cells, but it is happier on 12 is all. For a heavy truck, the xl motors are more up to the task, but even the "L" motor can easily get you into the 40s with the right batteries(batteries are the power-the motor only transfers this power to the truck-better batteries=better power). If you want to go 40+ all the time, the xl motors are a better choice.

[macfjej]

thanks all for all the info, if it isn't completely obvious i'm just begining to learn everything there is to know about brushless, i have just a few more questions before i make my order so that everything has been made clear

13.
two gearings for 9920/9L, one the regular gearing for max speed, and the other (if this is possible) to match a stock e-maxx, so about 29-30mph (14c), though i don't know if it willmatch for 12 cells as well. my GF decided to make the better of two choices and pay back some money she owes instead of getting a brushless setup this year, and i feel it would be easier to change the pinion/spur then to change the whole powerhouse

14.
do these require any sort of pinion puller? or just loosen the locking screw and take them off

15.a)
just to be sure, a 9L shouldn't have any problems with it's 1/8" shaft twisting should it? or do i need to get the 5mm shaft verion
b)
which comes with the combo? or do i need to specify

16. do you sell somesort of"plug" for the gaping whole where the other motor should be?

17.
is the 9920 computer programmable? does it need to be programed via computer?


again , thank you guys for all the help, it really is apreciated

[squeeforever]

to answer your questions:
13. you will have to change the gearing from 12 cells to 14 cells but not much although i wouldnt go for two different gearings because once you find the right spot i wouldnt change it since it will cause something to be to hot or possible fry something.
14. no, but i would grind a falt spot on the shaft so it wont spin on come off.
15. i would go with the 5mm because i have seen broken shafts. also, i would get the strobe slipper setup because you will eventually want to or need to get it and it would be cheaper in the long run to just get it from the start because you will have to change from 32p to mod 1 and the pinions arent to cheap for 5mm.
16. no plug although you could use one from novak. most people make a mount and use the motor screw holes to mount it.
17. the 9920 is computer programable but doesnt have to be. the programming cable isnt required, though.

[macfjej]

Originally posted by squeeforever
to answer your questions:
13. you will have to change the gearing from 12 cells to 14 cells but not much although i wouldnt go for two different gearings because once you find the right spot i wouldnt change it since it will cause something to be to hot or possible fry something.
14. no, but i would grind a falt spot on the shaft so it wont spin on come off.
15. i would go with the 5mm because i have seen broken shafts. also, i would get the strobe slipper setup because you will eventually want to or need to get it and it would be cheaper in the long run to just get it from the start because you will have to change from 32p to mod 1 and the pinions arent to cheap for 5mm.
16. no plug although you could use one from novak. most people make a mount and use the motor screw holes to mount it.
17. the 9920 is computer programable but doesnt have to be. the programming cable is required, though.

so you couldn't gear down the maxx to make it slower? hmmm

i never thought i would need awhole new slipper system i mean it's only going 8mph faster, and you think the 9L shaft would snap,, i could see stronger motors snapping but a 9L? and why would i need to buy the cable if i'll never need it? i'm full of more questions then when i started :W:



to clairify i want to know what gearing people use with the 9L, and whay gearing i'd need to go as fast as a stock e-maxx

[Batfish]

Originally posted by macfjej
so you couldn't gear down the maxx to make it slower? hmmm

i never thought i would need awhole new slipper system i mean it's only going 8mph faster, and you think the 9L shaft would snap,, i could see stronger motors snapping but a 9L? and why would i need to buy the cable if i'll never need it? i'm full of more questions then when i started :W:



to clairify i want to know what gearing people use with the 9L, and whay gearing i'd need to go as fast as a stock e-maxx

You can gear down to make it slower. However, with brushless systems if you gear down too much you may end up with excessive motor heat from the motor spinning at top RPM much of the time. The safest way to approach it is to change only one tooth at a time, checking temps as you go, until you get to a good speed and temp combo.

You don't "need" a whole new slipper system. There are many people who run the stock E-Maxx slipper system with more powerful systems than you're looking at. Then again, there are many people who melt spurs every run in the stock slipper system. The choice is really yours, and I would use the stock until it no longer works for your application.

As far as the 1/8" shaft snapping, that is a combination of torque and vehicle weight. On 12 to 14 cells, a standard 1/8" shaft should hold up forever, especially if you keep your truck under 11 pounds. A heavier vehicle with a more powerful motor would have a much greater chance of snapping the shaft, but it's pretty unlikely that a 9L on 12-14 cells in a 9-11lb truck is going to have problems with a 1/8" motor shaft. No guarantees, but you shouldn't have a problem if you're sticking near stock E-Maxx speeds.

[RC-Monster Mike]

Also, gearing for 12 and 14 cells could be the same gearing. There is indeed a "range" of safe gearing vs. the perfect ratio that must be used. The 1/8 shafts are pretty tough too, but..... if you have the pinion mounted at or near the end of the shaft, it is likely that you will have some trouble. I have seen 2 or 3 broken shafts and a bent shaft with the 1/8 shaft motors(Feigaos - the Lehner uses a hardened shaft and I haven't seen a broken Lehner shaft). I broke one myself with an 8L on 12 cells. The pinion was way on the end of the shaft(so I had it coming to me!), but consider yourself warned. The 5mm shaft is better.
The combos will include a 5mm shaft unless otherwise specified.

[macfjej]

Originally posted by RC-Monster Mike
I broke one myself with an 8L on 12 cells. The pinion was way on the end of the shaft(so I had it coming to me!)

why would you mount the pinion at the tip of the shaft,, as oposed to mounting it as near to the motor as possible?

and could somone give me an idea of a gear ratio that i could use?(9L)

[Sylvester]

Hello fellow Canadian, some people may run custom motor mounts and the motor might be spaced off as to where the spur is, so they have to put it near the tip of the shaft. I might be wrong.

As in gear ratio, i dont know, but i can tell you gearing, what slipper are you gonna use first off, id say get a ofna 51t spur with the strobe slipper, than try out maybe a 14 or 15t pinion.