is there anything that can be done to make the factory AC blow out much faster, or cooler, or both??

 

Several threads on this topic.
Put in a cutoff valve on the heater hose if it does not have one. If it does, make sure it works
Make sure all the ducts are connected and not leaking, this will require dash coming out.
Insulation under the carpet
Seal all the firewall pass thru's
Wrap the exhaust/install heat shields
There are some electrical mods that you can do to make sure you get full alt voltage at the fan when on High
Put in a C4 fan and motor

Corvettefaq has a good paper on this

 

thanks SIXFOOTER. i will check it out right now.

 

The original blower motor for my 74 was pretty anemic when it came to airflow. Luckily it went south and I replaced it with a Siemens unit which is much better. Before you get into a lot of fabrication I would try a new blower motor just to see if it makes a difference. It did on mine.

 

There have been a LOT of threads on this subject in the past few weeks (and in the past). Run searches for "A/C" and "cabin heat."

 

how well does the siemens blower motor work? does it spin faster than the stock blower? does it come with a wheel or do you use the old one?

 

Does the HIGH speed work on your switch?

 

I think that one of the reasons that our A/C's are so poor is the lack of air flow from the fan. I replaced mine with one from a C4. Numerous threads on this. All you have to do is build a spacer as the fan cylinder on the C4's is larger. World of difference.

 

Also look down inside the evaporator coil and check for debris. Leaves and junk find their way inside and block the airflow. Someone posted a picture awhile ago of one plugged solid with leaves.

There's allot of reasons why the A/C systems on our cars stink. Making the system work better by using the methods already mentioned are good but the bottom line is if the mechanics of the system aren't working properly you can add all the high speed fans you want and you still won't be cool. Mine has a VIR unit that have valves inside that are constantly sticking. I'm getting tired of throwing $$ at it replacing parts that still don't work right and am ready to replace the whole darn system with something modern. It's 30 year old technology that didn't work right 30 years ago!

 

I rebuilt my system last year with a new compressor, hose, VIR, O-rings, and blower motor. It blows 39o on a 85+ degree day, but the flow isn't the best. The car does get cold but I have to run it on high speed.

I am sorry that I didn't use the C4 motor.

 

I just replaced mine with a Napa blower motor, and a Metal larger fan. It blow very well, and i think its an 100000% improvement to what was in the car when i got it....
Sample
turn fan on
CLANK CLANK CLANK CLANK CLANK
feel the vent, no air coming out....
(my motor and can were broken, and the guy RAN TEH FAN EVEN THOUGH HE HEARD LOUD CLANKS AND THUDS) My fan was all ripped up in side.... Now i installed a higher perf motor and a larger metal fan that really blows.....

I have to put heat sheilds in my floors before i put carpet back down, and i have to seel my firewall up and recheck my duct work( i just put my dash back in and i think i have a leak i missed in my defroster vent... )

That new motor kicks, i love it and it was a easy install hardest part was taking out the pain in the a.. recovery tank

 

This is what I found when I removed my evap coil.



Neal

 

Um...chevymans 77
That debris is factory installed
Its part of the new "Recycle the environment" Act

All kidding aside
I bought a new Z/28 in 1984 and after a year or so it was running close to 220 degrees with the A/C on
I pulled the condenser and I found a black Hefty Bag...the big 33 Gallon size stuck between the radiator and the condenser.........but, surprisingly not a single coffee cup

 

Here's a thread I started:

Blower Motor & Fan test results

 

I agree with 95% of what TopGunn has said here except for his last sentence Quote: It's 30 year old technology that didn't work right 30 years ago![/QUOTE]

The A/C in my 73' Coupe will freeze you out of my car it is so cold but then again my car is an original 25,000 mile car and the components are still working like new.

My suggestion which is similiar to what TopGunn is speaking about above is to power wash or hose out in between your radiator and condenser first. One of the other things I have found over the years why some A/C systems work better then others was not just because of low freon but having a bad dryer in the car. Other components with age will also cause problems.

 

Fred, I wish mine worked as good as yours. Do you have the VIR in your system?? Actually that seems to be the root of the evil in mine, an old time refrig. company here told me they were a good concept but GM never put the $$ into them to get the bugs out.
Bill

 

TopGunn I really can't tell you what system the 73' has in it although I have worked on quite a few A/C systems over the last 36 years on different vehicles. I even installed A/C into a non A/C 79' Chevy pickup truck I still own where I took most of the A/C parts from a 80' Chevy Pickup wreck back in 2000. I used all parts from the wreck except compresser and accumulator. Actually it was here that I really found what a difference there was from using an old A/C dryer (accumulator) verses a new one. What a difference. I don't know exactly who did what to your system on your 75' but I would almost bet it is the same exact system as in the 73' although I am not 100% sure. All I know is back during the 70's I knew plenty of people with Corvette's also belonging to a Corvette Club back then and I never heard anyone complain about the A/C on their C-3 Corvette. Your system can work properly again if the right person puts their hands on it and does what is needed. I have owned my 73' Coupe now 24 years although I don't put a lot of mileage on it. All I have ever had to do to this system is add a can of R-12 freon to it maybe 2 or 3 times in that 24 year time period. The last time I added to it was probably 5-6 years ago. In hot weather like we are having right now when I go to a cruise I will either take my 73' or Street Rod because they both have air. My 67' just sits on these kind of days.