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71 340 E body w/factory A/C. Has anyone ever "up'd the ante" of the blower's output to move more air?

gtxncuda

gtxncuda

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Question for any E body HVAC savvy folks or restorers who have done their own rebuilds... Has anyone modified the system to get the blower (motor and/or squirrel cage) set up to move more air into the cabin when operating in the A/C mode? My simple mind says perhaps a faster spinning motor, or modified "fins" on the cage might help move more air? I'm thinking maybe some of you have tackled this and possibly found a different solution? Another motor from a totally different brand? (Mitusibishi, Honda, etc.) Don't shoot the messenger! FYI, my system is OE and using R-12 on a 71 Cuda. Yes, I know there are some very good aftermarket systems available, but I want to keep the OE system for appearances, (yes, even that heavy, Harley-like RV2 compressor!) but try to improve the function a bit. Any suggestions are appreciated. Thanks and Happy 4th to everyone!
 
If you take an auto repair school the A/C and HVAC section you will learn that the faster the air blows the warmer it gets. You can get a vent thermometer and test this in any car.

This is another area where more is not better.

If the car is hot inside leave a window down one inch for a few minutes and the hot air will leave the car faster since it rises and the cold air falls.
 
Check the voltage drops in that circuit.
I found it was only getting 10V to the motor.
My car had very low output and I took the output of the AC switch and routed it through a relay to supply the fan motor, it now has >12V
It more than doubled the air coming through that vents.
It now only blows on high, but I'm in FL and high is needed all the time.
 
Second the relay idea. And while you are doing one for the blower, may as well do a setup for the headlights as well.
 
You didn't say what kind of refrigerant you are running, but if it is R134a in an original AC system it is very inefficient and will never get very cold. In Canada, they never went to R134a but rather went to R12a which is almost as good as R12 and an average car needs about 14 oz. In the US they made the excuse that R12a was very flammable and R134a was not, but when did you ever hear of a car in Canada burning up because of the A/C gas? There have been millions of them up there with R12a. The R134a lobby in Washington simply won out here and the suppliers of $134amade big profits.

Fast forward, and now all the new cars use R1234, which is guess what?? Flammable. So much for the argument against R12a. The good news is that once a car has R134 fittings it is compatible with R12a you can replace the R134a with R12a legally. You can do a web search and find it. I did the conversion and my AC is now so much better running the original A/C components.
 
I got 134a in there now with ester oil .do i need to flush and use a different oil with r12a ?
 
No., The R12a kit comes with all directions. You can also download directions before you order. I used Duracool. Good website. They sell more than just 12a.
 
gtxncuda said:
Question for any E body HVAC savvy folks or restorers who have done their own rebuilds... Has anyone modified the system to get the blower (motor and/or squirrel cage) set up to move more air into the cabin when operating in the A/C mode? My simple mind says perhaps a faster spinning motor, or modified "fins" on the cage might help move more air? I'm thinking maybe some of you have tackled this and possibly found a different solution? Another motor from a totally different brand? (Mitusibishi, Honda, etc.) Don't shoot the messenger! FYI, my system is OE and using R-12 on a 71 Cuda. Yes, I know there are some very good aftermarket systems available, but I want to keep the OE system for appearances, (yes, even that heavy, Harley-like RV2 compressor!) but try to improve the function a bit. Any suggestions are appreciated. Thanks and Happy 4th to everyone!
Click to expand...
Ok, had a slow morning, so I thought I'd see what I could do for the blower speed of my 73 Rallye challenger. Well, running voltage to the blower motor on high was 7.5 volts!!! 13.7volts with relay Installed. My car is generally in good shape electrically, no chewed up harnesses with corrosion. I added a relay to give it just one speed, high . That motor really sings now. This is the cure, I promise you. 5 electrical mods all mopars need:. 1: bypass ammeter, 2: bypass dash light dimmer to run full voltage to dash lights, 3: headlight relays, 4: new 5volt regulator for dash if equipped and now, 5: blower motor relay!!!Nuff said. I will wire it up so the relay works only on high and low speeds will work, maybe, maybe not
 
I thought my blower was running a bit slow I;ll cheak he voltage thanks
 
Guys, thank you all for your replies. :thankyou: I'm a bit slow on my follow up. I am running R12 as the system is all stock. Based on some of your replies, sounds like I better check voltage(s) at the motor at the different speeds. I believe the resister IS working as the speed does change (albeit a small "puff" a to a slightly more "puff"). 😂.
Cheers all!🍻
 
Katfish said:
Check the voltage drops in that circuit.
I found it was only getting 10V to the motor.
My car had very low output and I took the output of the AC switch and routed it through a relay to supply the fan motor, it now has >12V
It more than doubled the air coming through that vents.
It now only blows on high, but I'm in FL and high is needed all the time.
Click to expand...
Hello Katfish, I've finally got my system recharged and running (somewhat) normally. I checked voltage at the motor and at the resistor and I'm only getting about 7.8 volts! No wonder it's so wheezy. I ran a wire from the battery to the blower motor and the difference was immediate and as you stated, basically doubled the output air. Can you please explain how you wired up the relay set up in yours? Using the FSM diagram, it looks like the dk green wire that feeds the blower is the one that ultimately needs to see the higher voltage. I'm also ok with only having it blow on high. Any assistance is much appreciated!
Dave
 
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