Need Your Help- Underbelly Radiator Design

[reithi]

I have a 73 Type 2 Bus with a JDM EJ20 engine.

On the last cooling setup I had two custom radiators in a series configuration which did work well in tropical weather.

I am now going underbelly with a 3mm stainless steel scoop, Champion EC2375 aluminum radiator and a Flex-a-lite 116 16" fan in pull configuration. The radiator inlet and outlet pipes have been modified to save vertical space.

The scoop is airtight and has inlet area of 25% of radiator core area (90sq in) as recommended by RJES. The radiator is angled at 6 degrees to aid natural flow of coolant, improve airflow to the core and create space for the fan on top.

Ground clearance to the lowest point of the chassis is 13". The idea is to maintain a minimum ground clearance of 9" from the lowest point of the scoop.

I need your help. What do you think of the design as far as design and cooling effectiveness are concerned? Are there any tweaks I should make?

....and apologies for the hand drawings.

Thanks

[babysnakes]

Apologies for hand drawn plans? Those look great. I have been pondering this to for a possible build. You have a scoop in the front for positive pressure, do you have a sealed exhaust vent to create negative pressure? I am only an a shade tree fool, but I think you need a wider/larger scoop out back to help pull also. I know you have a fan, but will it run constantly or have a thermostat? I'm on a learning curve.

[Wildthings]

I wonder how well the fan will be able to do its job with it being so close to the floor above it? Can't think of a better alternative at this point in time though.

[reithi]

Thanks Babysnakes.

[babysnakes]

[busdaddy]

No doubt Skillz will be along soon to tell us we are all barking up the wrong tree, but in the meantime here's some sciency stuff to consider in your design: https://en.wikipedia.org/wiki/Meredith_effect
Myself I'd be inclined to tilt the radiator the opposite way and have the warm air exit from below, no hot floor in the bus and possibly less restriction. I'd still run a scoop at the front and carefully seal up any gaps between the frame, floor, etc, to force cool air through when moving. Same with the exhaust duct, apply a little science and some sealing and you can create a venturi effect that pulls the air through it with the right shape on the exit.
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[tristessa]

While Oregon is admittedly not as warm a climate as Kenya, my current radiator lays flat with no shroud and thermostatic fans on top in a "pusher" configuration things relatively sealed to ensure airflow goes *through* the radiator not *around* .. and it's been cooling my engine just fine like that for about five years.

[chabanais]

I'm assuming you mean to hang it like this but with the radiator angled?

I agree with busdaddy that the radiator may be more efficient if it tilted the other way.
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[skills@eurocarsplus]

[Tcash]

Think bigger
http://www.wanderlodgeownersgroup.com/forums/showthread.php?t=22542

[awreed]

[reithi]

[reithi]

[reithi]

[reithi]

[reithi]

[skills@eurocarsplus]

due to location, your fan will come on in stop and go traffic....but so does every other fan on the planet.

if I sit at the dunkin donunts drive thru on a 80+ degree day and get behind some asshole with a suburban and 83 people in it, my fan will cycle once or twice.

my fan will also occasionally cycle on the freeway as well, but that is because it is a pusher fan. I would have loved you use a puller but it just hung down too low for my taste.

when I did have a puller installed, it didn't run on the highway. what you will soon come to realize is there is a series of trade offs in these conversions. I am running a way smaller radiator (expensive, but efficient) than everyone here and it sits 100% horizontal between the frame rails

when I do my camper over the winter, I may play with my configuration a bit to see what else I can come up with. but when you have something that works, it's hard to mess with favorable results
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[vwwestyman]

It looks like you're hoping to "tunnel" the air into the radiator with the scoop. (looks like it extends forward of the radiator). I can't think why this would be necessary.

I also don't think that any sort of scoop or whatever behind the radiator is necessary to pull air through. I don't have any. I do have a bit of plastic somewhat sealing the area in front of the radiator so no air goes above it from the front.

My radiator is mounted flat, with the bottom edge a little lower than flush with the bottom of the frame rails.

I'm wondering if your fan will fit with the shift tube and other control tubes running between the frame rails. I've got a fan mounted as a puller with no shroud and this seems to be just fine. All I really need the fan for is very occasionally in traffic. It is as wide as possible with still fitting to the right of the shift tube.

This pic is with the 4 inch scoop. EDIT: I think I raised the radiator up a little bit when I installed the 3 inch scoop. I forgot about that! So it is closer to flush than the pic appears.

More thoughts over in my build thread. http://www.thesamba.com/vw/forum/viewtopic.php?p=8214644#8214644
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