Airflow problems, need opinions...

[Panelfantastic]

Most of you know about my bus with the Ecotec. I'm having problems moving enough air at speed to keep it cooled down. At idle it does fine, will cool right down, but cruising, it heats up. My bus is a panel with the divider right behind the seats that seperates the cargo area from the front, if I take the divider down and run with the safaris up/open, it runs cool as can be... but I don't want to run that way all the time. The cargo area is too noisy and sometimes the safaris are too much (interstate driving) so I need a new plan.

How I bring in air is from single NACAs on each side... I even added small "eyebrows" to them to try and help...


I'm thinking of going to double sized NACAs and a more extreme hood...




How do I know if I'm making a tall enough scoop?

I even tried a small roof scoop which did absolutely nothing !! It would have to be 2-3 times taller to get in the airflow... Why in the hell didn't one of you stop me from doing that???



Ideas? thoughts? comments?

[yetibone]

How 'bout pulling air in from underneath the Bus. Along with the enlarged NACA ducts, you could use a large scoop and duct from the floor up to the radiator.

Or, with more dificulty, 2 remote radiators placed in areas that see more airflow. Somewhere up front, ahead of the axle if there's room.

[jhelgesen]

I think the roof scoop would have to be much further forward on the cab to work. Does your bus have the fresh air vent over the windshield? Could pipe that through the cab if you had it.

I like the idea of the scoops under the bus. Don't want them too low though, would scoop up a lot of trash. Have you tried some extra fans on the radiators?

[NO_H2O]

I think I would try something on the underside too. Might need some type of water trap/drain in the plumbing.

[Panelfantastic]

Thanks everybody. You all went the direction I was thinking too, underneath.
My bus isn't actually that low... no, really it isn't compared to some of the slammers I've seen, so I've got good clearance under there. Is the air any good? I can screen against debris and don't plan to do any wet weather driving so I think it is do-able.
I will work up some ducting ideas this week and see what fits... stay tuned .


EDIT:
Some things I forgot to add,
I'm running a pair of the largest fans I can fit, they do their job, it will idle at 180 degrees all day, there's just not enough fresh air coming in at speed.
The rad I'm using is four times the size that comes with an Ecotec, when you have enough air flowing, it runs 160-170 degrees even on a hot day.
They make duct fans for the NACAs but they're not worth it, they pull over 3 amps each and only put out 140 cfm...
I do have the windshield vent but it doesn't work/is blocked with the safaris open and that's how I ride 99% of the time...

[yetibone]

Yeah, the air's fine under there, just as long as you get it from in front of the engine compartment. Screen out any debris.

[Mikey 1972GL]

I agree with drawing air from underneath and it wouldn't hurt to use some kind of a screen. Also, the larger NACA ducks might be a good step if this doesn't work.

No original ideas, but I just thought another 2 cents wouldn't hurt.

Finaly, the bus looks great :righton: I can't wait to see it in person.

Mike

[Sandeep]

I too an a fan of grabbing additional air from under the vehicle. I'm using ducts for extra air to my oil cooler. You should be able to fabricate a scoop that is W-I-D-E and connects to the torsion tube and feeds some furnace ducting that directs air to your rad.

Sandeep

[Bullyboy]

I think the scoops would be fine if there was something that was drawning the air in either by a fan/blower or a natural flow. By having an opening of the air to go out the back of the van. have you tried opening the rear hatch a 1/2" or so to see if the air woud flow thru the bus any better. I would say a pop out window on the rear hatch would get the air flowing pretty good thru the back.
Just my opinion mind you.... it just seems the air either needs assistance getting in, or a natural source to get out. Kind of like the wind blowing into your bug thru the vent windows in the summer. then you pop open the rear pop outs and give that air someplace to go and whoosh its much cooler.
I'm no scientist, but I figured it is worth a try

[Panelfantastic]

Bullyboy,
I have added louvers to the rear hatch just below the window so it has a way to exhaust out the hot air. I also have a safari rear window and tried driving with it open, it didn't make any diff. Good ideas all around.
I've just got to get more fresh air coming in...

[Panelfantastic]

This is turning out to be more difficult than I thought. There is not a good place to come through the floor with my ducting... ideally, I would come up right in front of the torsion tube and it's a straight shot up the rear hump/firewall but there is too much frame and support in this area to start hacking. I would have to move forward at least a couple feet to clear everything. Imagine opening my side cargo door and seeing a pair of 6" tubes coming up out of the center of the floor and snaking back and up to the rear deck !
No, it's not a westy. No, I don't ever plan to camp in it or haul anything but butt, but that would just look like hell.
There is a fairly good place right in front of the rear wheels but then the duct catches everything the front tires can pick up... and if they hung down very much at all (which they need to do, right?) they would really stick out.
More head scratching to do...

EDIT: New twin NACAs ordered today to replace the singles.

[NO_H2O]

Weld up a wide/low profile duct from sheet metal then transition to a round duct, kind-a like a woodstove hood.

[boygenius]

I say go with the air from under the bus. Don't ruin the clean look of your bus with extra scoops. I would say what everybody else said, run a large wide scoop under your bus the entire width of your bus. Place a metal mesh over the front to keep trash bags and such from clogging your cooling system. Although also note that the airdam which you spent so much time making will cut down on the air that flows under your bus just like it is supposed to do. Have you considered any radiator additives like water wetter. Try to picture your bus in a wind tunnel and ask your self where would the air be flowing around the bus. You will have good dense air in the front but the rest of the way back the air would be turbulant. If you want to get good source of air for the radiator you might want to run the ducting all the way to the front of the bus and cut some intake holes into the front air dam. You could make some large rectangle shaped ducts to channel the air to the engine compartment. Paint them flat black so they are not as visable when looking at them. Also you might want to make the ends adjustable since they might need to project a little from the front to get into the good clean air. Just a few thought to consider.

[NO_H2O]

Why not pick up the air at the air damn (small round ducts) and transition to to a 2"x10" sheet metal chase under the floor, then transition to a round duct and into the back at the rear tray.

[Panelfantastic]

Originally Posted by NO_H2O

Weld up a wide/low profile duct from sheet metal then transition to a round duct, kind-a like a woodstove hood.

That's definately the plan for the mouth of it but I think I have to keep the round duct a decent size too, at least 3" maybe 4" to get some volume in...


Lots of good ideas BG. I'm already using water wetter and a 50/50 mix on antifreeze. Don't worry, after the roof scoop fiasco I'm done adding scoops to the outside. That was a toooough lesson to learn . The real reason I'm switching to the double NACAs is because when I taped it up there, I just liked the way it looks! If it happens to catch a little more air...bonus!
You brought up a very important point about trying to imagine where the air flow is... unfortunately, all I can do is guess and my guessing has been ultra sucky. (see roof scoop cluster) Running ductwork from front to rear is darn near impossible with the beam and steering stuff in the way so I've got to stick with catching it near the back. I'm gonna make some cardboard dummy boxes and fool with hangdown and clearances this coming weekend.
If anybody gets a brainstorm, lay it on me.