12xl and 9920
 

what would this motor do for me on 12 cells, its going to go in e-maxx with
14"wheelbase front and rear spools, its built for the sand and deep muddown in fla., so i got to keep the amps down and alot of torque, i got some narrowed jumbo kongs so its going to put a strain on things, and the 9920, i like the holiday price from mike so i think i'll get that as well

It'll have plenty of torque! If you use the 9920's max cell count of 20, which is 24v, you'll get a little over 30k rpm on the 12xl.

It will have great runtime and torque, but you wont be too happy about the accell/topspeed on 12 cells. For 12 cells a 7xl would be great for the 9920!

i think the most i"ll go is a 5s 6000mah, so the 9920 will be fine you think, i was going to also get that ubec for it

i dont need speed i need torque without burning any thing up, i" be turning 8.5" tire in deep mud

Yes! The 9920 on 5s with a UBEC would be a great setup - and if you want it to run even cooler you could use a fan on it too.

yeah i got a 3" 12v computer fan from radio shack i had used for a while i hooked it up just like a ubec so it just stayed on when bats where hooked up, worked great it was big enough to cool the motor also,

would you say the truck would be close to stock speed/acceleration with the 12xl and twelve cells, its around 20,000 rpms.

It might be a bit slower, or maybe the same speed. But you sure will get some awsome runtime with amazing torque.

i would be happy with stock,maybe play with the gears, thers no more racing going on, i had a hacker c-50 motor for the e-maxx it screamed i tore up all the gas trucks at a local track, but burned up the hacker speedo in the process, so i'm going back to what the truck was before i was racin, a mudder ,and i just dont want to see any smoke when its turning those big tires

If you going 4s or 12 cells. I would run a 9xl accually. You can drop the gearing down a little more for power. If you going to run such a big tire.
I would run the hb pro diffs with the 4.3 ratio. It would make the trans
last a little better. Lower gearing more torque to wheels so less amp draw as well.

Yes, I agree with Leroy;

The 9XL would be a better choice for the maxx on 5S lipo/ 12 cells to start with..

sound good i did not know those diffs had a lower ratio, a 9xl so i could maybe get some more wheel speed out of it, i wont be using thoe big tires all the time but when it happens i want to know every thing will handel it.

But the 9xl would still be a better choice. The 12xl actually, you would have to gear the hell out of it. Even a 10xl on 4s, I have to gear it 20/51 for any good performance. Also, the temps stay lower too. If you make the motor work too hard to pull juice it can get hot as well.