Need help with 4S racing setup

I am about ready to give up on my converted mbx5 and go nitro (I hate NITRO!) Over the last three years I have spent tons of money.

Recent failure has been with a medusa 36-50-2200 with a MM with cap and fan, ubec, geared 14/46, running 4300 4s zippy packs. The speed controller and batteries stayed cool but the motor got way too hot 240f. Geared 12/46 and the motor stayed cool but was too slow and wound up so fast that it was very hard to control.

Here's the track dirtburners.org
I need to be able to run 15min or preferable 20 min mains.

I'm thinking neuenergy 5000 lipo, neu 1512 geared at 12/46?

Thanks in advance for any help.