If the cells holds 3.5 volts at 143 amps 4s will be at 2000 watts.
The buggy probably took less watts than a emaxx for sure.
50 mph is not bad though.
How fast do you want to go?
Are you going for speed or racer?
If you want alot of speed and power go up on voltage.
If you don't want to spend alot of money. A 7xl may be a good choice.

yea this is not for raceing just insane speed

Actually, in all honesty. It's not really the peak power of the motor that will get you high speeds, it IS the size of the motor, we are talking real world here.

I took my emaxx to 50mph with only 580 watt, what did I use? I powered it from two large DeWalt 820 sized drill motors, and dual EVX esc. The setup had massive torque enough to spin the tires at up to 30mph on pavement (with a lowered maxx). However this setup was a amp monster. They are nice motors too though. For only $30 dollars a motor, and the cost of a second EVX you can have some pretty potent performance.

what did you use to measure the watts and what did you use to measure the speed? 580 watts to reach 50 mph? my eagletree show me quite some different value with a lighter setup on a lower topspeed.. and the experience of the users here will be different as well.

Torque doesn't make topspeed, the BHP's/watts will. torque will help you get to topspeed.

Getting an MT to 60 mph normally took 20 cells.. (which equals about 2000 watts)

Well here is a thread. Two different size motors. Same truck. Same speed.
Same wattage. http://www.rc-monster.com/forum/show...=david+goliath

Well, no i shouldn't say that, it was more like almost 700 watts, i was running 16.5 volts, it's 580watts on 14.4 volts.

If i didn't make myself clear, what i mean is real world use... a Lehner XL may take it quite fast, but it would get very hot. These motors got hot, but thats because they were running to their peak, and they are brushed motors.

Peak power is irrelevant with speed (well you need a decent amount), it all has to do with the continuous power output. Yeah, the torque wasn't near the torque as with a BL setup, but then again thats exactly my point! I mean, if power was all that matters, and it took 2000 watt to get a ~10lb truck to get to 60mph, then your runtime would be like 2 minutes... LOL

You know what i mean now don't you??

Again; WHAT did you use to measure both speed and power? got an eagletree or anything else?

700 watt for 50 mph with brushed?
that's like 525 watts on the output shaft of the motor (75 percent eff.) which would make it possible to run 50 mph with 2S of good lipo cells. (not talking about runtime, just about the speed) i don't see that happen,

this is what gave me the idea that you don't have got much experience with power and brushless. No offence, but trust me, 70mph takes an awfull lot of power (Watts)

My lightweight e-maxx takes 1500 watts to get to topspeed and to stay on it takes a rough 1200 watts (and since it weighted about 6.5-7lbs with that setup, i don't think it's a heavy maxx, and a much lighter maxx isn't very possible)

no, no it's 700 watts AT THE SHAFT power. And seeing that the motor is only 60% efficient, it takes alot more power to pump into the motor. What im trying to say is that larger motor at the same power as a smaller motor will take it to a higher topspeed, the reason is heat, and continuous power vs. peak power....

what did you use to measure that power and speed then? (stil curious about this)

Your 700 watt 60 percent big motor setup takes 1150 watts. would run much hotter than a small 94 percent eff. motor with 1150 watts input. And that small more efficient motor would have had a higher topspeed than your big high torque motor setup.

If you ran the truck with same gearing as you did with the 14.4 volts to get the 580 watts. Which comes out to a 40 amp draw. My calculations say that if you go up to a 16.5 volts the amp draw will in creas as well to about a 47 amp draw. That would put it at about 775 watts. If the motor is only a 60 % efficent. You had to have about 1300 watts going in. at 16.5 volts You are at an almost 78 amp draw.

Im sure the peak amp draw is 100 amps or more for those things. They are a 5 pole brushed motor. They spin up to 20,000 rpm.