Hood scoop direction?

[Retired Roughneck]

Here is a weird one for ya LOL
i wanna put a scoop on my hood but not sure which way to face it?
i run it in all weather.
20 degrees cool to 100 degrees hot.
also travel in the rain a lot along the Oregon and Washington coast.
i just put a new all aluminum radiator in.
and also installed a new lower fan shroud that was missing?
its running great but i would like to keep the engine bay cooler.
for when i cross country in the desert.
its so compact and i feel that its not getting enough air circulation.
if i face it forward it will force air flow in.
but i worry about water getting on the alternator.
i guess i could always put duct tape temporarily if its raining cats and dogs LOL.
if i face it back at least maybe it will let hot air out?
a friend said for there to be a vacuum it needs to be 2-3'' from the window.
maybe the window may push air flow into the engine bay?

is there any aerodynamic specialist in the forum LOL
any thoughts would be appreciated.
thanks in advance.

 

[Mr P]

Look at drag race cars. A cowl induction hood faces the windshield and is so close to it that the high pressure at the windshield actually pushes air into the scoop. For a forward scoop to get air, it needs to be "in clean air", above the turbulence of the front of the hood.

Race cars use scoops. Most all street cars do not. Why? Cost to benefit ratio...the benefit of the little bit of airflow is offset by the intrusion of all kinds of water. Rust, and worse, ice in the winter can do serious damage.

A front air dam (under the front bumper) lowers air pressure under the engine, so air from the radiator exits easier. Fender vents on some sports cars also pull air out of the engine bay.

 

[Mr P]

And you would not want to add air to the engine bay, you need to remove the hot air that has entered through the radiator/condenser.

 

[nikitis]

Your bus should get decent air inflow from the front grill by design. Putting the scoop in reverse with the opening towards the Window could double as a defroster as well, and add better air flow as an exit rather than an intake I would think in the case of your bus.

Also better for the rain while driving.

 

[magnakansas]

Telephone me, let’s talk air flow.7852077600.

William

 

[Retired Roughneck]

Aw man William i just finished it LOL
i may call ya anyway thanks so much?
thanks everybody for the input.
much appreciated.
i went with rear since i am only looking for some cooling or ventilation.
its far from the window so there probably wont be any type of induction, vacuum or forced air down it?
there is a bumper scoop before the radiator.
so i am hoping the vent will simply let some heat come out the top?
its not very big.
the hood was fiberglass so it was easy to do.
it only gave me a specific spot to cut out but it worked out perfect!
i can always change hood direction, close it for winter or simply remove it if need be?
im putting 500 miles on it this weekend with 85-100 degree weather.
we will see what happens LOL?

 

[nikitis]

Got you a Mopar bus now!

 

[Mr P]

You can put small pieces of masking tape on and near the scoop to watch air flow. See vid for effect on an airplane wing...

 

[Retired Roughneck]

Hot Dam Mr P,
i woke up in the middle of last night and thought of the same thing LOL!
simply run a piece of tape across the opening loosely.
then see if it sucks or blows?
idle & highway?
maybe add more stuff like the wing if need be?

cool video
i love aviation and have knowledge of airplane aerodynamics!

hopefully get a chance today?

the only thing im concerned with is maybe taking away some air circulation from the back of the motor over by the dog house door?
probably be ok though since everything is open underneath the motor and tranny?
on a E chassis everything is such a tight fit........

 

[Retired Roughneck]

OMG what a difference!
test drove today
so here are the specs.
the scoop is 10'' from the window.
i put loose tape on it for testing.
at idle it has a little blow and lightly pushes the tape out which will be good for sitting in traffic.
( i will try to post a short vid? )
at 35 mph it goes on a vacuum and lightly sucked the tape in.
i have the Edge insight so i know what my motor is doing.
so last year operating coolant temp was 200-210 degrees.
would see 230-235 going uphill's, sitting in traffic or a really hot day.
i installed and upgraded to a new all aluminum radiator & installed a missing lower radiator shroud.
that brought operating temp down to 190.
then i did the scoop.
in 10 miles the thermostat opened up @ 187 like normal.
a 75 degree day it took longer to hit the new operating temp of 180 degrees.
so thats a 20 degree drop in operating temp.
it ran 175 with various stops in town.
when i would pop the hood it was around half the engine compartment temp as before.
which is also what i was going after.
may be a little on the cool side but that should help motor longevity & fuel milage?
i hear 160 is the minimum for the power stroke so 175-185 should be good to go?
i will definitely close it during the winter.
i did let it idle when i got home to see what would happen.
after about 5 minutes in 75 degree whether it reached/stabilized @ 190.
with warm air slightly blowing out the scoop.
so on a 80-100 degree day sitting in traffic or creeping in road construction should be under 210?
the big test will be this weekend of 500 miles.
200 mountain.
300 warm valleys.
so far things are working out pretty good!