[jhautz]

Have you checked that there is no drag anywhere in the drive train? If you have bad bearings or something rubbing or difs that are shimmed to tight or something else causing drivetrain drag it can drasticaly effect the heat and runtime. I ran the 1512/2.5D on a R1Pro and 5s with no problems at all. I didnt even have a fan on it. and from my experience the Mm can take a little more the the R1Pro because of the R1Pros lack of a heatsink to disipat the heat. Id look into the rest of the setup to see that you arent introducing some other form of drag the MM should handle that no problem with a fan. If not, try the hole mod on the MM case. Drill some vent holes in the MM case so air can get in and aid cooling. SOme have even put holes in the bottom of the case and put a 2nd fan on the bottom as well, but those are ht guys running the crazy hot setups. What you are describing is powerfull, but not insane. Also having adaquest ventalation on the ESC will help alot too. So if yout dont have it put some cooling holes in the body.