Airflow problems, need opinions...

[crewcab1964]

My buddy and I were reading through your dilema. There's a bunch of good suggestions from other people in the forum. I'm sure you don't want to deface your vehicle anymore than you have to. These were some of our observations.

1. At idle, no problem
2. At speed, problem-This may be due to the characteristics of the bus,
when you are pushing through the wind, you are displacing the wind in a
turbulent manner around the bus, not enabling your ducts to work
properly. Even if the air is flowing across the ducts it could be creating a
vacuum, starving the cooling air to the radiators by reversing the airflow
like a venturi. The closest thing we could describe it as is a sandblaster,
compressed air passes at high speed across an orifice picking up sand for
desired affect.

The wind tunnel idea is good. If you don't have access to a wind tunnel, place streamers (construction marking tape) around the ducts and radiator louvers and have someone follow you and video tape you at speed to note how the streamers react. If they push in towards the back you may have to reverse the route of the air to the radiator.