Electric fan???

To match the airflow of an engine-driven fan, you need a powerful electric fan. The 2-speed Taurus fan move a lot of air and is popular with hot-rodders. If you can fit an engine fan & shroud, do so. My 1985 M-B diesel has both an engine-driven fan and pusher electric fan. The electric fan turns on from refrigerant temperature, so its main purpose is to cool the evaporator when idling. Even that isn't sufficient, since the AC gets noticeably warmer when sitting at a long stoplight. That is also true for my 2002 Chrysler minivan, and yes I verified that both fans turn on. Once you start moving 30 mph, the AC gets noticeably cooler.