Key to success with a BL setup are the batteries. The better the battery, the less it will limit the power of your setup. The better the batteries, the more volts they will produce under a high load.
We are not here to advice you the biggest most expensive setup money can buy. Our goal is to help you pick a system that suits your needs.
How much power do you need? That depends on your own wishes. Keep in mind that 4S lipo (about 14 'normal' NiMH/NiCD cells) are more than enough for serious racing. 4S lipo can bring a relative heavy buggy to 56 mph. 35-40 mph is enough for most tracks.
Bashing with lipo's? Not advised. The cells have got low protection (thin polymer bag) and the material inside the cells is rather soft and a pack is easily wrecked with too rough abuse. For bashing NiMH or A123 cells are safe. Some manufacturers are producing 2S Lipo packs that use protection. (Peak-Power, Flightpower Trakpower packs)
Make sure your lipo's aren't jiggling around in the vehicle, protect them and handle them like princesses..
What's that S and P thing in lipo's?; P means Parallel, for example; if two 3.7V 4000mAh cells are put parallel, the result will be a 3.7V 8000mAh cell. While 2 in Series would make it a 7.4V 4000mAh cell.
With 2 in parallel, the power a pack can produce will double.
Speaking of lipo's; that C thing, what is that? The C means capacity, a number which based on 1 hour; (the energy a battery can deliver in 1 hour) when a discharge of 20C is permitted on a 4000mAh cell, that would be 20X4 (4000mAh means 4Ah) = 80A. Since a Lipo cell can't stand a discharge voltage lower than 3V, discharging them too deep might cause in all sorts of misery.. (Shortens the lifespan of the lipo-cells and in worst case scenario it catches fire.)
Because of this, you need a device that measures the voltage of the pack/cell and throttles down your vehicle when the lipo's hit the bottom. This can be done by the use of an LVC (Low Voltage Cut-off)
Some controllers have got one built in. (Quark/Mamba-maxx/MGM) with others you need an external device which protects your lipo's
You need to pick a motor that suits your needs. Basically, a smaller motor will spin up sooner, and the truck will feel more agile. A larger motor however will give you more torque, which you can use with a shorter gearing-ratio. A smaller motor normally needs more RPM and gets hot quicker with a higher load.
when you power a buggy, truggy or other relative 'short ratio' vehicle, you need a lower KV motor with more torque.
The KV of BL motors are the RPM a motor makes on 1V. While Feigao's numbers are without a load the Wanderer/LMT/Neu motors are given with load. (more realistic when you use the speed calculator of BrianG) The more turns a BL motor has, the higher the internal resistance will be. the longer runtime you will have.
For most applications (MT/truggy/buggy) you can take a Wanderer/Feigao XL can. They have got plenty of torque to throw around a 15 lbs truck. And they work very well in lighter (8 lbs) trucks/truggies and buggies too.
If you go thru the shop, you'll notice a large variety in motors and prices. Quality comes with a price.
Basically; a more expensive motor, (high end, such as Neu, Lehner) uses segmented magnets. The magnets are made from thin slices instead of larger lumps. These segmented magnets make the motor more ideal on partial load. it's not said they run more efficient on full power, but they are more efficient on partial load; meaning they heat up less fast. The energy is used to make the motor turn, and not hot.
The wanderer/feigao/nemesis motors are fair cheap, and with the right care (cooling if needed) they last for a long time. Since the end-bells are pressed/held in place by a few screws, replacing the bearings is done with the ease of breathing.
Many users on RC-monster have great success with the feigao/wanderer/Nemesis motors. They are good motors for the money; nothing beats them in terms of price/performance.
However; there are better motors available. The Neu motors for example, if you have got them both in hands, you can see the difference. they are built tough. Look good, and they are 4 poles. Because they are 4 poles, they will not work with a BK controller (micro, warrior). They need a controller such as the MGM or a Quark. A 4-pole motor is harder on the controller. (on the same RPM as a 2 pole) 2 times as hard. The 4 pole motor needs 2 times as much signals to make 1 turn than a 2 pole.
Speaking of which; a 2 pole and a 4 pole, what does that mean? Simple; it's the number of North and South poles the rotor is divided in. so you can imagine it would take twice the 'trouble' to make 1 turn.
A high end lehner motor (like the 1940/1950 etc) are very good motors with 2 pole rotors. Meaning they can be used on basically any car-oriented controller.
When the differences are important to you, when any second counts, and if you can swing it; a high-end motor will be a good choice.
I used several different setups, and my biggest surprise was when I ditched my schulze/Bigmaxximum setup and got the 7XL/9920 instead. I didn't noticed a difference in power and the 7XL was smoother in starting. The bigmaxximum got hot, and so did the schulze controller (it thermalled like crazy, and it needed a large fan to keep it's head cool)
Keep in mind that the more powerful your setup, the faster the drive train will wear on your vehicle. A revo and an E-maxx use rather weak diffs. (typical 1/10th) Upgrading to aluminum diffcups housings needs to be considered, replace when you break them isn't the smartest thing. You can use the gears for a longer time when you upgrade. Good thing the 1/8th conversion for the Revo is nearing completion.
Using BrianG speedcalculator, motor calculator and his ‘solver’ can offer all the help on calculating what motor/gearing suits your needs. If you take the time to fill in the fields, you can help yourself out.
they can be found here