okay the bigger the number say 5700kv is that going to be faster than the 4700kv motor?

Kv is basically rpm per volt, so the bigger the kv number, the higher the rpm for the same voltage. For a 2S, 4700kv would mean a rpm of 34,780rpm, 5700kv would be 42,180rpm. With the same gearing and battery, 5700kv would be faster than 4700kv.

For Castle, their motor is 4600kv....

Thank now i understand. back in the day Novak and others used to put 8.5 turns 6.5 turns and so on. i think il get a 5700kv

The 5700 rips... I just put one in my son's SC10 and it's silly. Just make sure you use good batteries, these motors only perform their best with quality batteries.

only SMC lipos a seller on ebay has them for 87.99 for the 5700kv setup with the esc all new in the box.

Without any punctuation marks or capitalization it is hard to figure out what this sentence or sentences is supposed to convey to us. Following what we learned in grade school regarding the fundamentals of written communication, is a good thing. Don't we deserve a little more effort?

I put a Sidewinder/5700 combo in my 2WD Slash and it proved to be too much. There was so much wheel spin, it was slow getting started. It was a handful to control when it did get hooked up. The 4600 is the better choice for something like a 2WD Slash.

I've actually dropped down to a 3500, but only because I wanted to be able to run 3S.