How to keep my old school Mamba Max from overheating on 3s.
 

I'm running a feigao 8L with the MM in my crt.5 Temps, Motor - 150, ESC 160, 3s lipo 90.

I'm geared to hit 56mph using the 3s lipo and I like it that way, lol. The problem is the esc gets hot and begins to cut out (no motor or servo control). Is this the issue running a BEC will rectify. Do I do that first or figure a way to put on a fan?

I did have a 2650kv with a MMM in the car, but I just burned one of my other MMM's so this one is getting slightly down graded.

I would definitely try the external BEC first, it can only help.

The original MM uses a linear BEC instead of a switching BEC so it is working really hard on 3s.

Bec and external cap will help alot

I've ordered a bec via Texas's suggest. Whats a cap?

Capacitors on the power input of the ESC. The ESC has a few built-in, but many people add extra. Castle makes a cap bank, or you can buy caps and make a bank yourself. You need low ESR caps, and make sure to leave overhead on the voltage rating (get higher voltage rating than you plan to use, it's harder on the caps if they are running at their max rated voltage)