I just ran my mbx5 with 7xl & MM on a 11/51 or 4.6 ratio. I disconected the fan for this test i got about 8 1/2 plus minutes before thermal. I temped the controller it was about 175- 180. I then connected the fan & the temps dropped to 120 in less than a minute. What do you guys think ?. I could go lower on the pinion but i would loose to much speed