airbox: why refoam hot air flaps?

[DanHoug]

so i'm rehabbing my airbox (and doing something secret with the dropping resistor!) and while i fully get why you'd want to replace the seal for the cold air duct, i cannot imagine a good reason to bother with the hot air ducts.

they just divert between the windshield and the floor. if there's leakage past either or both, no big deal. it's all warm air, no heat loss, just maybe a few CFM from where you'd asked it to go. right?

-dan

[Paulbeard]

Except maybe you want to defrost your windshield right away and not have all that air go to the knee ducts. If you don't care where it goes, you can certainly simplify the controls: just set them all open except the heat and just use it.
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Currently -> Frida: 87 Tizian Red (mostly) Vanagon GL Westfalia w/ 2.0L ABA conversion
Formerly -> Steward of a 73 Super Beetle (Beater) and 67 Beetle 1300 (Little Max) both names by POs

[DanHoug]

but it is an incredibly small amount that bypasses the metal flap. as i look at my box, with the foam completely gone, they still seal quite well. as i say, a few CFMs will get by either flap but it would appear to be a very small amount.

foam on the air entrance, bottom seal to rear ducts, and around heater core seem crucial.

-dan

[IdahoDoug]

I noticed a nice decrease in wind/air and whistling noise from my dash after redoing the foam. On the freeway, it is remarkably lower and I think it was whistling through all those cracks. My ventilation also went from weak at the windshield or where I wanted it, to strong where I wanted it.

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[dhaavers]

^^^ x2

Quieter & more efficient when directed all up -or- all down...

- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[DanHoug]

ah yes, the noise. i'm going to block most of my grill air intake to lower the plenum pressure. it forms quite a pressure that DOES cause noise unless you have all the ducts open. which in cold weather, you close the fresh air and it over-drives the heater core with too many CFMs.

heck, i'm half considering gluing the passive doors closed so the only air is thru the fan cage. probably just go with some round foam pipe insulation stuffed in the intake or the Vanistan kit. or make my own flap.

-dan

[IdahoDoug]

As always it will be interesting to see what you come up with, Dan!
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[DanHoug]

well, here ya go.... a new take on the heater resistor. this is a harness from the AC fans. it uses two 80 watt resistors in parallel to give variable speed to the rear twin fans. so... using this harness and then mounting the resistors directly in the air flow, this doubles the wattage capacity of the resistors for a single fan, cools them, and they should last forever. while i like the ease of changing the Jeep resistor, i didn't like the glowing elements where a leaf or combustible could smoke. these don't get that hot.

the fans from the AC are a perfect replacement, aside from the plug instead of spades, but using the AC harness, i use the plug too!

[DanHoug]

this heater resistor BTW gives the option for 4 speeds. but, with the 4 spd AC fan switch used in place of the 3 spd heater fan sw, you lose a true off as it relies on additional control to turn the AC fan off completely. i would need a 5 position switch to have 4 + off. so i chose to use ALL my speeds going thru the resistor, eliminating the direct 12v line to the motor as it was just too loud and fast. the 3 speeds going thru the resistor are all very 'useable'.

-dan

[dhaavers]

There ya go then...nice clean install!

As always, well thought out, documented & posted...two thumbs up.



- Dave

PS: No lube tube to the motor bearing? ...or is that next before you button it all up...???
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[DanHoug]

hmmm.... lube tube, didn't think of that. i've got a Mulendore port i made in a futile attempt to free the original fan, which was locked up VERY tight.

Hammond organs use two lube tubes for the the Leslie motors spinning the horn and bass port. then in the tone generator itself, it uses cotton threads fastened in an oil tray and the end of the thread is wrapped around a bronze bushing on the spinning shaft! capillary action draws the oil to where it is needed.

given that, maybe i'll put a felt wick on the end of the motor shaft.. something that will hold some oil drops. it could easily be re-oiled thru the port periodically and would serve to keep some dust out. and it think i have just the wick... a felt pad from a distributor used to lube the points rubbing block!

standby!

-dan

[Sodo]

If it's all apart, why not just run a small hose or steel brake line or copper from your Mullendore port to the target bearing? Can it be downhill all the way?
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[dhaavers]

FWIW, my lube tube runs straight up to the driver side defrost vent...EZPZ!




- Dave
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86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[Steve M.]