Originally Posted by Happywing

As a customer before me stated. Something around 2400Kv. My 6.5 at 3100Kv was almost right for my 1/8 buggy. I had to gear down a bit (10 or 11/46) to keep it cool enough to make a 20 minute main without a controller thermal. I don't know the Kv rating of the 4.5, but that motor is not suitable for racing. A few of the guys around here tried them over the summer. Fast as all heck, but it thermals the controller quickly. I think the longest anyone lasted with the 4.5 was about 11-12 minutes on a cool day. So, the 4.5 is suitable for bashers. The 6.5 is very nearly suitable for racing. I think perhaps a 7.5 (or whatever you want to call it) at 2400Kv would be excellent for buggy's on 4s.