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Discussion Starter #1 (Edited)
I decided to take the advice of some of you that brought up the valid issue of the heater blower motor being in the engine compartment. I made a one off fiberglass housing to use the FFR Vintage Air heater core. The fan is a 120mm high volume computer fan and it seems to move as much air as most production cars. It fits, no blower on the firewall and seems up to the job. The fan also glows blue when it is powered for what that may be worth.... :wave:
 

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I decided to take the advice of some of you that brought up the valid issue of the heater blower motor being in the engine compartment. I made a one off fiberglass housing to use the FFR Vintage Air heater core. The fan is a 120mm high volume computer fan and it seems to move as much air as most production cars. It fits, no blower on the firewall and seems up to the job. The fan also glows blue when it is powered for what that may be worth.... :wave:
Make sure it produces enough pressure to keep moving air once you have ducts on there. Volume and pressure aren't the same thing. I played with a couple computer fans and none of them could move the air with enough pressure, even if they had the flow rate when I bench tested them.

I ended up using a 4" bilge blower in the fender.

There are computer fans that produce a ton of pressure, so I may have just had bad luck. I have a 20lbs fan from a VAX that'll knock someone over from across the room. :D
 

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Yeah, it may move free air but it won't build static pressure. I have a feeling once the tubes are run you'll find it drops off quite a bit. I would think you need a squirrel cage blower or similar to keep the pressure.
 

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Discussion Starter #4
The Computer fan is rated at 92 Cu. Ft. a minute and seems fine on the "door" side. I agree the hose may be a issue. If you have a source for a cage fan small enough I can work that out. On one hand I don't plan to drive the car much in cold weather but I do want a heater even if it not the most powerfull unit.
 

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3K,

Airflow is not the issue, pressure is. If you haven't got the pressure to overcome the static loss, you will get no airlfow. Give it a test run before mounting is by adding some hose to the fan outlet. Hope it works out for you.

Perry
 

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I did something similar - I used the Vintage Air heater unit and fabbed up a box for it. The fan I'm using is a 145cfm 4" bilge fan - it's great for a single vent, and I'd say adequate for the two vents simultaneously. Here's a few photos. I have it pretty much finished and trimmed out since these photos were taken.







 

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Discussion Starter #7
Wow CobraDMV looks like you have it going on. I found another 120mm computer fan rated at 240 CFM. Thats way more than the 90 plus one I have. I'm all about more is better I just don't want a ugly box on the firewall.
 

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Sounds like this is getting over technical.... With a top on the roadster, just dumping it out is about all that is needed. David lives in the South.. doubt if the car will be used in sub 0 conditions.
I had NO tubes on my car and heater worked ok. Now, I really like the idea of one in the trunk also.. As leaky as these cars are, even with a top, If you plan on a lot of really cold winter driving.. 2 of these suckers would be great.
 

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Discussion Starter #9
Hey Al, I have a extra box all fabbed up if you want it for Roadster number 2!
 

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Discussion Starter #10
Sounds like this is getting over technical.... With a top on the roadster, just dumping it out is about all that is needed. David lives in the South.. doubt if the car will be used in sub 0 conditions.
I had NO tubes on my car and heater worked ok. Now, I really like the idea of one in the trunk also.. As leaky as these cars are, even with a top, If you plan on a lot of really cold winter driving.. 2 of these suckers would be great.
I rode in Al's car about 5AM once and it was nice and warm on a cool morning.
 

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Wow CobraDMV looks like you have it going on. I found another 120mm computer fan rated at 240 CFM. Thats way more than the 90 plus one I have. I'm all about more is better I just don't want a ugly box on the firewall.
3K - in the Pacific NW, it can be chilly in the morning, and hot in the afternoon (although it's usually chilly in the afternoon most days as well!!), so I needed a setup that will give me both hot and cold air. I have an inline valve in one of the heater hoses, so in the morning, it's open for hot air to blow. Then in the afternoon, close the valve for cool air - that's why there's a line going up front to the brake duct opening - it will vent the cool air in from there, rather than the engine compartment.
 

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anyone know where to buy a brake duct inlet for a 4" hose? I need one to mount to the back of the body brake duct inlet them run to my 4" bilge blower
 
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