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.

[Panelfantastic]

Crew hits on probably what I think is the biggest problem...
Any of you guys that have ever had a van or SUV knows what that back window looks like after a few weeks with no bath... absolutely filthy! The air just swirls back there, I'm probably getting a ton of turbulent air across the rear right where I'm trying to exhaust my cooling. If it was shooting down that back hatch, it would pull a serious suction on the louvers and my problem would be fixed... BUT, it would take a pro-mod wing to reach up into the airflow and make this happen so that puts me back to bringing in air from underneath. I think NO_H2O is spot on, but I would have to start the chase right behind the front beam, make it almost like a thick belly pan (that would be a plus!) and funnel it down to a couple of round ducts dumping up into the cargo floor. I seriously think that once the cargo area is charged with fresh air, the fans will take over and do it fine without having to run plumbing all the way up to the fans (oh that would look sooooo ugly).


Rich, I sure hope I don't have to start from scratch and move the rad, this is what I get for trying to outsmart you UK guys!

[Steve C]

Hi

Love your bus. A while ago I saw a baywindow with a Subaru motor in it, he had a radiator mounted flat under the belly of the car. Loking at your setup, if the heated air just went down over your motor and out under the rear bumper you would get more flow I feel, like when you have an oil leak on a bus it ends up all over the back window.

Steve C

[Panelfantastic]

Got in late, I'm beat. No pics tonite.
This belly pan/air chase is gonna be the ticket. I did take a few minutes to look under there and this is really the ideal way to go. My duct would be 26 inches wide and 5ft long and 2 inches thick. There is a perfect place right behind the front suspension/tie rods to open the front of the chase up into a mouth that could be 5-6 inches thick without it even being noticable. I can funnel the rear into two 3 inch PVC ducts.
I'm excited again, this idea rocks! Thanks everybody for the support and guidance!
It will take a week or so for me to gather up everything and start working on it... I will report back as it develops.