Electric fan in engine bay?

[Tom Y]

I would like to mount a fan or fans in my enine doors blowing out. Like the 12v auto rad fans. Thinking of running when the engine is on and also 10-15 minutes after shut down. Good  or bad idea? Ideas for a dc timer? Thanks Tom Y   

[lostagain]

Assuming you still have the stock radiator fans set up, you have to make sure the bottom of the engine compartment is as wide open as possible for air to escape. If the bottom is not open very much, louvers or grills in the rear doors will help. But I would think that air going down and out the bottom would cool the engine compartment better than out the back doors. I don't see that fans would help while the engine is running. Fans would be a good thing though for after shut down to cool the engine compartment so the bedroom doesn't get too hot.

JC

[luvrbus]

Tom, I ran electric fans on my tail gate on a Eagle used those only for shut down to cool the bedroom I bought mine with the thermostat control so if I forgot to turn it off it would when the temps fell never was a problem for me even when driving sometimes I would forget and leave it running 


good luck

[Cary and Don]

We have a set up on our 4107.  The only vent it has is the radiator and the bottom.  The tail gate is solid and the transmission side was solid.  We added a fan on the transmission side pushing out.  There are two bilge fans that suck the heat off the top of the compartment and push it out at the bumper.  It used to get so hot the tail gate was hot to the touch.  It's cool in there now.  We run them almost all the time unless it's cold.

Don and Cary
1973 05 Eagle
GMC 4107
Neoplan AN340

[pipopak]

What about NACA ducts?. Watch this video at:
NACA Ducts Wind Tunnel Test: Baja 5B
and note that the air speed is around 20 mph.

[bevans6]

NACA ducts are great at pulling air in from a laminar air flow (smooth, non turbulent) which would probably be the case on the sides of the bus near the back, but I think the goal in this case is to exhaust air from the hot engine compartment.  NACA ducts won't do anything for that, but they would dump air in if you make a way for it to get out.

I don't think that fans will help while the bus is at speed enough to matter, the low pressure area in the rear of the bus should move air, but like clifford suggested I think they would do a lot to cool the engine after shut-down.  I usually  open all the doors at the rear to let the air out.  I also usually forget to close them, and spend the night with the engine open to the world...

Brian

[TomC]

After turbocharging and air to air intercooling my 8V-71, I had heat to contend with.  I cut two 14 x 14 holes and installed aluminum louvers on the back door.  Made a big difference since the rear of the bus is a vacuum going down the road.  Walking behind while the bus is idling, you can feel the heat going through the louvers.  Good Luck, TomC

[pipopak]

If you open the engine compartment at some point where the air pressure is low, like in the back, NACA ducts will pull fresh air in for free.