wheelies?

[Finnster]

I am personally not a fan of the 9920. I had one I had trouble with, and was not particularly impressed with the contruction. It is not enclosed, so there are a number of small electronic bits to break off if you are not careful. Plus if you do is a long repair time having to sent it back to Germany. Plus, from all the accounts I've read, the 9920 is not nearly as smooth as some of the newer escs like the Quark or the MMax. I can def say the MM is very smooth and is nrealy cog-free. I can nearly crawl with it. The real advantage of the 9920 is high voltage. It is the only setup that can reliably run 6s. The quarks should, but several here have had mixed results above 5s...

The greatest thing about the MM is that it is completely programmable by usb/computer. You don't have to do this, but is really neat if you want to adjust all sorts of custom settings. Plus CC is in the USA and has legendary customer service if something ever does go wrong. Running above voltage specs is not covered under warr, but as mentioned, the CC engineer said it can techically be done, and many others inc myself have confirmed it.

You have to disable the BEC but pulling the middle wire pin from the connector and run a ubec. Ubecs can be found for as little as $15 if you are not planning high voltage, but will required whatever setup you use. A samll fan is also needed for extra cooling. My esc stays below 125F.

If you are looking to run no more than 4s/14cells then the MM is what I would get. Its only ~$165, where as the 9920 is ~$190 and the Q125 $280. Id rather put that $120 into a better motor like a neu or LMT. 5s/16cell+ ==> quark, mgm or equiv.

The only heat concern I am having is from teh motor (8xl.) A neu/ lmt will run cooler and could poten be geared for a bit more speed. Overall I am very pleased with my setup.

[BrianG]

Originally Posted by Finnster

The only heat concern I am having is from teh motor (8xl.) A neu/ lmt will run cooler and could poten be geared for a bit more speed. Overall I am very pleased with my setup.

Finnster, I am curious as to what temps you are getting with the 8XL. When I used it in my Revo, it ran about in the 130-140 range. On 14 cells it ran great, even on my heavy truck. If you go higher on the cells, you start hitting the high end of 40krpm and would heat up more.

[Finnster]

Originally Posted by BrianG

Finnster, I am curious as to what temps you are getting with the 8XL. When I used it in my Revo, it ran about in the 130-140 range. On 14 cells it ran great, even on my heavy truck. If you go higher on the cells, you start hitting the high end of 40krpm and would heat up more.

My post in another thread:

"The bad news was the motor peaked at 165+ after ~45 mins of hard running on the dirt (jumps, high speed runs, powerslides, climbing and other bashing goodness.) The HS was only getting to ~125, so I'm worried poor contact may actually be insulating the motor some. Had a blast tho.

Strangely, the rear steel output shaft for the tranny got to ~165. I was careful to have the drivetrain freespinning when I built it, and had to do a little chassis trimming for the shafts. I did notice the shaft moving a bit under high throttle, so I'm thinking a bearing is busted. I do not see any signs of wear between the chassis and the driveshaft. Hopefully addressing these two issues will bring down the heat some, else I may be looking at a Neu sooner than later.."

I still have to look at this Brian. I do remem you were running a 14t, but in a heavier truck. The motor is still only on 14cells. If I could get teh temps to below 150 I would be happy. Its mostly in the 140s, but did get pretty hot at the end (tho the last pack was 12 cells, but I would think this would have the opposite effect,...??:032: )

Like mentioned above, the rear tranny output shaft is getting really hot, so something isn't spinning right. I didn't even notice it until the end when I put my hand underneath to pick up the truck and nearly burned myself. The shaft is moving under load, so prob the bearing is blown. I need to better seat the motor HSclamp as well, but without a lot of contact force its never going to be ideal.

EMaxx:
The motor is great, I just have to get the heat squared away. Tons of power and Tq. Its nearly undrivable in the grass as so much TQ has the F wheels always off the ground. I would estimate speed to be high 30s to ~40 mph. As fast or faster than my rustler with a BL novak GTB/5.5. Really its plenty fast for me. I rarely get to top speed in the dirt. If all you want is to go up and down the street really fast, then maybe you'll want a bit more, but I don't see the point of the MT if you don't take it off the street. :025:

RC-monster does sell the 8xl in two versions, one by faegio and one by BK relabelled as the Wanderer. One is blue, one is purple. Mine is blue. Basically the same motor, tho I've heard the kv are slightly diff. Really its pick your color.

[BrianG]

Ah, maybe drivetrain drag causing the motor to work harder.

You said that you'd think that 12 cells would run cooler than 14 cells. Well, I thought the same thing, but when I first put Revo V1 together (feels like ages ago), I used both 12 and 14 cells and found that the motor was hotter and runtime was worse on 12 cells. Some of the helpful people here mentioned that it might be because I was on the throttle harder with 12 cells to make up for the difference in power from the lack of the 2 extra cells. Maybe that's what is happening to you?

[Finnster]

Originally Posted by BrianG

Ah, maybe drivetrain drag causing the motor to work harder.

You said that you'd think that 12 cells would run cooler than 14 cells. Well, I thought the same thing, but when I first put Revo V1 together (feels like ages ago), I used both 12 and 14 cells and found that the motor was hotter and runtime was worse on 12 cells. Some of the helpful people here mentioned that it might be because I was on the throttle harder with 12 cells to make up for the difference in power from the lack of the 2 extra cells. Maybe that's what is happening to you?

I started to write a but OTOH, but then erased in in regards to the 12 cells running harder. I was hard on the throttle with all the packs as I was really trying to do a stress test w/ the MM and the 25mm fan, so I'm not sure it was really driving style. I was wondering if the motor is causing a higher amp drain due to the decreased voltage. I would think that both voltage and amps would just go down, that why I erased the thought before I posted it, but without some data logger I am just guessing.


Didn't mention the C motors, but I would prob rec one of those so you won't have to buy the extra HS clamp. I have a 380C and its great, but haven'yt tried the XL in C-cans.. Any would be good tho

[BrianG]

Yeah, it's kinda hard to say. It made sense in my case though. It was just a thought. (BTW: what's OTOH?)

As far as I know, the ESC doesn't pull more current to make up for lower voltage. I think it simply outputs a PWM pulse proportional to throttle using whatever voltage the batteries can provide. Normally, for a given load, an increase in V = increase in A. However, the motor is a coil and there is inductance involved, so I'm not sure if that is a factor somehow.

Edit OTOH=On the other hand. Doh!