My single port Alky Controls with M15 nozzle, both banks on my '13 are fairly equal. When I would check on my Aeroforce gauges, both banks were running 9 to 10 on the rich side. Even with my new tunes where I can datalog now, both banks are still fairly equal. Could be the 50/50 mix on the meth your using, might be the upstream 02s. See what your tuner says.