AC improvement
Thread Starter
Instructor
Joined: Feb 2018
Posts: 194
Likes: 14
AC improvement
Have a 1972 454 automatic. AC is less than ideal. Do not want to install Vintage Air. Have been told that I can upgrade the blower fan with one from a C4 and that C4 fan will produce greater air volume than a C3 fan. question: Is that true and is it a bolt in project? Will it help? Thanks. BTW, have already installed a shot off on water to heater core and insulated lines under hood, for what that is worth. Live in Florida and we are cooking down here.
Team Owner
Joined: Feb 2003
Posts: 54,139
Likes: 9,447
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Higher fan speed will reduce the time the cold air spends on the evaporator to get the cold air. Checking the efficiency of the condenser, evaporator and other components is where you should check. Also making sure all the insulation and heat shields are in place to help reduce the heat in the cabin.
Thread Starter
Instructor
Joined: Feb 2018
Posts: 194
Likes: 14
Thanks for reply. Checking system has already been done. Also installed dynamat insulation in cabin and installed a removable hardtop. Air coming out of vents is about 10-15 degrees warmer than similar point in my 1973 small block.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,607
Likes: 7,053
From: New Or-leens Loo-z-anna
Higher fan speed will reduce the time the cold air spends on the evaporator to get the cold air. Checking the efficiency of the condenser, evaporator and other components is where you should check. Also making sure all the insulation and heat shields are in place to help reduce the heat in the cabin.
Those numbers sound good until you factor-in the cubic feet of the shop. On a 100*F day the shop air temp is 85*F on High fan.
This helps...install it EVERYWHERE...
UNDERSIDE OF DECK LID & HARDTOP, INSIDE STORAGE-BATTERY COMPARTMENTS, ALSO.
My car was 130*F at the interior firewall with factory insulation on a 95*F day...
I removed it all and installed HVAC insulation....now the interior firewall is equal to outside air temp.
Thread Starter
Instructor
Joined: Feb 2018
Posts: 194
Likes: 14
Engine temp om gauge shows normal. No engine overheating but it is a 454. Radiator and shroud and seals all replace a couple years ago due to a leak.. Will check outlet temp at 1500 from center vent. Thanks
Thread Starter
Instructor
Joined: Feb 2018
Posts: 194
Likes: 14
Bit more info. Temp at center vent is 53 degrees at 1,500rpm. Temp at drivers side vent is 43. Air volume with fan on high is about one half the air volume produced by fan in my 1976 small block. Thoughts?
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Le Mans Master
Joined: Jun 2019
Posts: 7,670
Likes: 2,474
From: Indiana
Someone posted recently i cannot find about the junk that can accumulate.
here is removal on big block but i know you are not removing the evaporator but has details.
https://www.corvetteforum.com/forums...-cleaning.html
someone will chime in on cleaning.
i read one who used camera and mini claw with compressed air
here is removal on big block but i know you are not removing the evaporator but has details.
https://www.corvetteforum.com/forums...-cleaning.html
someone will chime in on cleaning.
i read one who used camera and mini claw with compressed air
Racer
Joined: Dec 2012
Posts: 487
Likes: 66
From: Rhode Island
put a 91 vette fan in my 70 and easy replace I. did not like how slow the 70 fan was so bougt the fan from cc and the plug from eBay all you have to make is the 1/2 in spacer so the fan will fit connect the purple power wire and the ground wire. I redid my whole ac unit and getting 43 in. cab sitting in my 95 deg garage
Pro
Joined: Nov 2019
Posts: 648
Likes: 353
From: Portland, Oregon
I cleaned the evaporator with it in place, but had enough disassembled to be able to snake a skinny vacuum extension to the upstream side while directing compressed air at the downstream side. It was easier because I had the heater box out and was servicing the fan. Add fiber-mat insulation at the air plenums to keep stuff out in the future. As mentioned above, the fan motor came with a wimpy ground wire that corrodes at the attachment. Measuring current draw before and after will tell you if an improvement was made. Two types of Dynamat; thin, heavy stuff for sound insulation and foamier stuff for heat. It’s still rather thin and carries a weight penalty. Reflectix gives excellent bang-for-the-buck. Extra insulation can be applied to both the inside and outside of the evaporator box. Not much area on the inside, but the outside can be covered completely with a 1’x2’ sheet of high temp stick-on. On an all-original car I found the 1’x2’ sheet stays in place without using the stick-on, so it’s easy to remove. The center console was getting very hot; found the horse collar missing and replaced with pipe insulation. Cooler thermostat helps a little. I liked Jebby’s idea of removing the control arm flaps for extra engine bay ventilation.
Charlie
Charlie
Just another Corvette guy
Joined: Feb 1999
Posts: 8,518
Likes: 3,865
From: Palm Springs, CA.
Yes, the number one problem with Corvette A/C systems is a plugged evap core. The best fan in the world cannot push through all the debris that gets clogged up there. The factory fan is more than sufficient to do the job but it needs a clear path to function properly. Check this recent thread:
https://www.corvetteforum.com/forums...on-a-78-a.html
Cheers, Greg
https://www.corvetteforum.com/forums...on-a-78-a.html
Cheers, Greg
