Air flow direction in D-Pillar?

[Californio]

Hey folks,

I'm thinking of installing a 9" radiator fan in my passenger side D-pillar (since I have a conversion engine there's no air filter there.)

This is to reduce heat in the engine compartment. When you stop after a long summer drive, the heat from the engine filters upward and keeps the bed area WAY too hot. So I'm trying to vent that out as quickly as possible.

What I'm not sure of is whether there's any advantage in keeping this fan running while driving. That would depend on the direction of the air flow in the D-pillar. Intuitively it seems that the flow is downward through the vent while driving, then upward when stopped, but it could be that so much air comes from underneath that the real flow is OUT the D-pillar vents while driving, not in.

Any ideas on this one?

Anybody installed such a fan?

thanks all--

[240Gordy]

it is defiately downwards when driving, you will be fighting a losing battle trying to push air up and out the vent.

when stopped your idea will work, but I am thinking you might want to pump cool, fresh air down and over the engine area rather than pump the heat up the vent, as some of it will get radiated into the interior as the air passes through the pillar.
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[Californio]

So next question, is it worth installing a fan reversing switch for use while driving or is there such a massive air flow from the vents that it's a waste of time (and watts?)

Another concern I have is that the alternator on my Tiico is touching the deck lid and gets super hot. Partly due to lack of ventilation. Any ideas (it can't be lowered) other than chopping a hole in the deck lid? Smaller diameter alternators out there?

[Christopher Schimke]

The air at the bottom of the pillar is near stagnant when the pillar is open to the engine compartment. The air pressure in the bottom of the pillar and the air pressure in the rear portion of the engine compartment are very close to the same when at speed. In other words, running the fan under those conditions while driving would yield little to no gain. However, once you were stopped, the fan could definitely be used to draw the hot air out of the engine compartment. It would be cool to set up the fan on some sort of thermostat or timer (like a turbo timer) so that it would run for a certain amount of time after the engine was shut off and then shut itself off automatically. Most turbo timers have a maximum run time of about 10 minutes.
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[Californio]

I'm thinking a thermostat would do the trick nicely.

I've found some low-amp fans at absoluteradiator.com. Their 4" motorcycle fan draws 1.9 amps and moves 124 CFM. Since the fan will be running with the engine off, I'm thinking it's best to go with something will run for a while, like 1/2 hour, with lowest current draw.

One big problem with summer heat in these vans is that you're essentially sitting on an entire radiant heating system, given the radiator, the engine, and the sets of coolant tubes underneath. Not much to do about it but maybe this fan will help at least in the back.

[wildenbeast]

I would think your idea could work but why not use two of the 4" motorcycle fans ( http://absoluteradiator.com/files/3009-3018.pdf ) and mount them by the tail lights so that they could pull the warm air out of the engine compartment while your van is running? You could then have the fans on a thermostat control or tied in with your ignition so that they are cooling the engine compartment on long uphill grades, a hot day, etc. The main drawback is cutting away some metal near the tail lights.
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- Bill, '93 Eurovan Syncro Weekender (2.5 manual ACU)

[PDXWesty]

I'm trying to really wrap my head around the necessity of this. The heat should be completely dissapated within 1-2 hours of stopping. Do you need it gone quicker? Is it really worth all the time and expense to install fans? Once I park, I open the hatch and doors and things cool off quickly.
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89 Westy 2.1 Auto

[Californio]

As far as the need goes, if you've ever tried to camp in Nevada in August, you know what I'm talking about. You pull in and stop, it's 100 out, 120 in the van, and on top of that you have exhaust pipes at 300 or whatever they are sitting right underneath you--basically you roast. I also have a Syncro with ladder, gas can, and spare mounted on the back, so I don't open the hatch very often. The heat accumulates inside the engine compartment and the rear of the van so that, if you stop at 7PM, it's still roasting in there by the time you want to eat dinner. Anything I can do to counter that, I will.

There was a thread a while back on opening up the rear taillights for this purpose. I don't remember if anyone did it or not.

I think the 4" fans are ideal for this application as it would be nice just to leave them running for a while--the engine takes a long time to cool off and these fans aren't going to cool it any quicker, just change the air in the compartment. At 1.9 amps you could do that.