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Looking to increase airflow from the HVAC blower

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Old 05-01-22, 01:20 AM
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Looking to increase airflow from the HVAC blower

I've been wanting to do this for years but haven't quite known how to go about it or if there was even anything I could do. I was thinking about adding an inverter to bump up the power to 18v, but I'd rather not do that anymore. So I was wondering if anyone has found a more efficient squirrel cage that can be swapped in. The extremely cold air from R152A substituted for limited air flow, but I won't be on that refrigerant anymore and I want to make the AC work really well.

I know the AC wasn't the focus on these cars, so I'm prepared to be disappointed.
Old 05-01-22, 11:16 PM
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Pull everything out and re foam it. The air traveling through the ducts is likely escaping out the sides. Re foam it and it will blow harder
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Old 05-02-22, 10:20 AM
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Also the blower motors are just weak from time and use. I have seen that you can retrofit an Rx-8 blower I want to say. Not sure if the stock part is still available or NLA.

This is something I need to do, mine is getting pitiful.

Re-foaming helps a great deal but that's a HUGE HUGE job to do.

Dale
Old 05-02-22, 11:58 AM
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Oh yes.... you really gotta want it lol pulling all that stuff apart is not a joke. Icon garage has a really detailed video on the process so you can have a idea. Likely worth it in the end but boy oh boy....
Old 05-02-22, 11:13 PM
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I re-foamed everything several years ago. Didn't really change much lol. I have my dash out again now for about the sixth time (for different reasons) and I figured I'd look into it before putting it back in. Maybe I'll look into getting an RX-8 squirrel cage. Thanks, Dale!

What really did help was getting ice cold air with keyboard duster, but I'm not doing that again this time. I can never get the charge right and keep nuking compressors lol.

Last edited by speedjunkie; 05-02-22 at 11:15 PM.
Old 05-05-22, 10:48 PM
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I ordered a replacement FD blower motor and an RX-8 blower motor (only for the squirrel cage) from Rock Auto and they came in today. The pics below are comparisons between the FD motor and RX-8 motor.

Aside from the one mounting point, the bottom is almost identical. It even has the same connector.
by https://www.flickr.com/photos/159205146@N07/, on Flickr

However, the squirrel cage is a different story. They spin opposite directions. And while I was hoping for a more efficient design, they look pretty much identical aside from facing the other direction and spinning opposite. Also, the RX-8 squirrel cage bolts on.
by https://www.flickr.com/photos/159205146@N07/, on Flickr

I was thinking about still swapping the new motor in, but the original motor still kicks just as hard when starting as the new RX-8 motor, seems like it still spins just as fast. And the new motor isn't exactly the same so it doesn't bolt in quite right, the RX-8 motor is more similar. So I'm abandoning this idea unless someone finds a more efficient cage design, and even then, this fan blew so hard that I guess it's just the design of the ducts that kills the airflow. It's not even worth wiring in the inverter to get more voltage to it.

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Old 05-05-22, 10:58 PM
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Thanks for doing the investigation on this.
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Old 05-06-22, 07:43 AM
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Speedjunkie, two things off the top of my head since it looks like you’ve covered most. While you have the dash and blower out, make sure the air intake under the wiper cowl is clear. A mouse built a nest in mine and besides the smell, the airflow was diminished. Also, it should only have one of the wiper cowl plastic plugs installed under the plastic cowl itself. The second is the blower motor resistor. Easy to overlook. I’ve seen them heavily corroded at the terminals. It could be not getting the proper voltage to the actual blower motor terminals. Worth a look before capping it up.


~ GW
Old 05-06-22, 09:45 AM
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Glad you tried it!

My concern is my blower motor being weak with 139,000 miles on the car. I have an air speed meter I bought once to mess with this project, someday when I have time I'll dig into it again.

Dale
Old 05-06-22, 11:48 PM
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Originally Posted by gdub29e
Speedjunkie, two things off the top of my head since it looks like you’ve covered most. While you have the dash and blower out, make sure the air intake under the wiper cowl is clear. A mouse built a nest in mine and besides the smell, the airflow was diminished. Also, it should only have one of the wiper cowl plastic plugs installed under the plastic cowl itself. The second is the blower motor resistor. Easy to overlook. I’ve seen them heavily corroded at the terminals. It could be not getting the proper voltage to the actual blower motor terminals. Worth a look before capping it up.


~ GW
Weeelllll, I just put the dash back in last night lol. I removed the blower motor with the box installed but before I installed the dash again. I'll have to remember to look into that next time I have the dash out. I'll have to look at the cowl to see what you're referring to regarding the plugs. I think I know what you mean, but if it's what I'm thinking of, I think I've only ever seen one plug. I think I had the resistor out a few years ago, I'll have to look at that again. That would make sense if my airflow when installed is bad but it's better when just jumping it to a battery like I did yesterday.

Originally Posted by DaleClark
Glad you tried it!

My concern is my blower motor being weak with 139,000 miles on the car. I have an air speed meter I bought once to mess with this project, someday when I have time I'll dig into it again.

Dale
Yeah they weren't that expensive, I think I paid about $60 for both of them before shipping and taxes, so it's worth trying. And the paperwork says I can still return them too. The same exact aftermarket (Four Seasons) FD motor from NAPA is $215 and I got it for about $30 from Rock Auto. Weird.

My car has about 200k on it, so I wouldn't worry too much about your motor lol. Although that depends on usage also, our climate out here is usually pretty awesome so I doubt I've used my motor as much as I would have if I lived in Florida lol. I would be interested in seeing your results with an air speed meter though. We have some at work, I'll try to remember to test it sometime when I take the car again.
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