Originally Posted by Skiddins
It's also very dependent on how good of a fit the heatsink is around the motor.
The cheaper heatsinks seem to only make contact with the motor can in a couple of places which makes them virtually useless.
The LRP I have is very tight to get on.
Yeah, a lot of things sold in the RC market as "heat sinks" aren't really heat sinks and would more properly be called fan holders. If the "heat sink" you got from Yeah Racing is the one I'm thinking about it is really a fan holder -- it doesn't do anything to help disapate heat it just holds the fan.
A heat sink is like a radiator. It should fit tightly to the motor (maximize motor surface to heat sink surface contact). It should provide a large increase in surface area (maximize surface area to allow heat to disapate).
I'm running just heat sinks -- no fan -- and get about a 20*F temperature drop over no heat sink. They have 9 fins and stick up about an inch from the motor. I'd guess their total surface area to be about 18 sq inches.