blower motor

[Jason72]

Does anyone know of an upgrade for the blower or fan to get more volume from the vents? I had the whole system apart and all seams are sealed and doosr operate as designed. Just looking for some more volume from the vents. thanks

[GatorDog72]

I took my back window out, does that count? I got 560 air now instead of 460. 😂

Make sure your heater core and ac coil are clear of debris and the vents are sealed up tight. 

I don’t know of any aftermarket blower motors that increase the airflow. 

[cbolt]

I installed a relay that hooks the blower motor directly to the battery and uses an in cabin switch to operate the blower motor on high because I had the exact same problem. I believe, but am not certain, that the harness that runs from the horn relay to the blower motor has resistance in it that causes the blower speed to be slower than it should be when connected straight to the 12V source so instead of replacing the wire harness I just added a relay. (Honestly, I cannot recall exactly where the hot feed for high speed comes from, but that would be the suspected problem harness. It may not be from the horn relay)

[RON T]

My high speed is the same , but I’ve never traced the situation down.. sounds like a new winter project!:)

[Jason72]

1 hour ago, cbolt said:

I installed a relay that hooks the blower motor directly to the battery and uses an in cabin switch to operate the blower motor on high because I had the exact same problem. I believe, but am not certain, that the harness that runs from the horn relay to the blower motor has resistance in it that causes the blower speed to be slower than it should be when connected straight to the 12V source so instead of replacing the wire harness I just added a relay. (Honestly, I cannot recall exactly where the hot feed for high speed comes from, but that would be the suspected problem harness. It may not be from the horn relay)

I read about that on a chevelle site yesterday. Going to try it when I get the car running again. Current installing fuel injection. Maybe later next week. Thanks

[Chevy Dave]

On high speed, on a factory AC car, the blower motor is fed by a #12 purple wire from the relay on top of the evaporator case. A # 12 orange wire feeds the relay directly from the battery terminal behind the battery.  The short run  of #12 wire has very little resistance. You should have full battery voltage to the blower on high, unless the relay has corroded contacts.

[Scott S.]

As I mentioned in another post, I installed a blower motor from a early '80's Suburban into a '77 Silverado standard cab. 

You may want to look into a blower motor for a larger car or wagon. 

[Jason72]

4 hours ago, Scott S. said:

As I mentioned in another post, I installed a blower motor from a early '80's Suburban into a '77 Silverado standard cab. 

You may want to look into a blower motor for a larger car or wagon. 

Good idea!! Thanks 

[Scott S.]

Jason, just keep in mind the width of the fan wheel.... I found the Suburban's was a touch wider, so I had to switch the original on to the motor. 

[Chevy Dave]

I have researched trying to find  a more powerful blower motor without success. It looks like the Impala station wagons use the same one as the Monte Carlo. If anyone finds one that fits our cars, please post the model number of the better one.

[Scott S.]

Hey Dave,

I did a quick check on blower motors (without fans) and found a couple numbers you might want to check...

They are listed for Suburbans and vans, but the cross reference chart said they will fit our cars.

AC Delco 15-80875 & 15-80666 (both come without the fan)

According to the G.M. Squarebody site, they seem to like the improvements using the early '80's version in their '73 to mid '80's C 10's.

Continental makes a couple as well...... PM102 & PM105

Hope that helps. 

Scott.

[Jason72]

Here is what I ended up doing… I installed a new blower with my factory fan. Engine not running it felt a little better. Did a few tests and ended up removing the orange wire from the horn relay to blower relay. Replaced the relay with a new one. Ran a 10 ga with inline fuse from the alternator stud to the fan relay. (I’m running front end accessories from a 1997 Chevy truck) Then a 10 ga from the relay to the fan. I spliced in the wire from the resistor too.  I then soldered a 10 ga wire to the blower motor housing and grounded the other end to the frame rail. When the engine is running it made a significant difference in air volume. 

Edited August 3, 2024 by Jason72

[Scott S.]

As Tim Taylor always said.....MORE POWER !!! ruf,ruf,ruf

Glad you got it figured out.

[Chevy Dave]

I was mistaken when I said that the feed to the blower relay came from behind the battery. A black # 10 wire goes from the horn relay to the inline fuse and then it becomes a orange #12 to the relay.  I will change the orange wire to a # 10 , the purple wire to the blower to a #10 and the ground wire to a # 10 based on your results. After much research, I don't think any of the 60s through the 80s blower motors turn  any faster than the original ones on the 1st gen Montes.  The increased performance from the 80s Suburbans comes from a longer blower wheel. I don't think we have room in the blower  housing to install a larger blower.  If anyone has been able to install a longer blower wheel please let us know.

[Scott S.]

One suggestion I've thought of would be to build a spacer that fits between the motor flange and the main housing. That way you could keep the bigger fan and force more air into the original ductwork. A 3-D printer would be helpful for that.

Like I said before... Switching just the motors worked in my Silverado..... But maybe the original motor was that bad that a new one made that much difference.

Then again, climate control packages for Canada might be different too..... 

[Chevy Dave]

I would think that the portion of the blower that would be inside the spacer and outside of the air stream would not increase the air flow very much, if any.

[cbolt]

Or, you could just wire a relay to make the blower motor hard wired straight to the battery. Easy peasy. 

[Scott S.]

18 hours ago, Chevy Dave said:

I would think that the portion of the blower that would be inside the spacer and outside of the air stream would not increase the air flow very much, if any.

Seeing as hydraulics and pnumatics work on the same principles, using a bigger or faster impeller into the same size pipe would increase the flow pressure.... It's a closed discharge system and the air has to go somewhere. 

But it's just a suggestion.....  Scott.