Boosting AC coldness and air flow

[EdwardSams]

About five years ago, we installed a vintage air system on my 1970 and it works pretty well.

Unfortunately, for where I live, there is often a lot of traffic which means we’re running at idle and when doing so the air conditioning is not as powerful and doesn’t stay as cold.

Right now I have a clutch fan, would replacing that with electric fans solve this issue? if so, based on the research I’ve done I apparently might be opening a whole new can of worms by making that conversion.

All guidance welcome. Thanks.

Ps, I’m running a sbc350.

[PbFut]

Having a Champion 4row and upgraded fans I can say I am in the process of going back to original type big block setup. I have spent a lot of time and money on the electric setup only to find it less reliable and not any better than a properly set up BB system.

[dmjlambert]

I have heard (but not yet done anything on my truck about it) that if you weatherstrip all around the condenser to block off the ability of any air to get to the radiator without going through the condenser first, it is supposed to help. Also making sure you have a good seal around the fan shroud so no air could get sucked into a space between radiator and shroud is supposed to help. The idea is make sure all the air being moved by the fan is air that originates in front of the condenser. Some people add a pusher fan in front of the condenser (electric).

[Lee H]

Are you running a shroud, is it in the correct position with the fan blades?

[Stocker]

Assuming your fan clutch is in good operating condition, is it a standard unit, or heavy duty? Best fan seems to be a factory style 7-blade. These come on factory A/C trucks, and a HD fan clutch is recommended with them. If all that is up to par, it wouldn't hurt to add a pusher fan or two, but you will likely need to upgrade your alternator & wiring to handle the extra electrical load. I would not switch to electric fan(s) and eliminate your factory system, though some have done it with good results.

If you're not sure what type fan clutch you have, look at the faceplate. Standard has a smooth steel faceplate with fins around the outer edge, and heavy duty has a finned aluminum faceplate.
More info here: https://www.haydenauto.com/en/produc...-types/thermal

[Sheepdip]

No recommendation here, just telling what works for me on a factory A/C unit

Champion Aluminum 4 Row with dual fans and shroud from Champion, temp triggered with a toggle option to run fans continuously, which I do in slow traffic on a hot day.

My only real problem on super hot days and slow traffic for extended periods is belt heat fatigue, once moving all is good again. Because of this I change all three belts annually.

[Stanco]

A smaller water pump pulley will speed up the fan. A larger crankshaft pulley will speed it up even more. This is what the factory did on trucks with AC.

[weq92f]

.

I have tackled this problem doing these things over past several summers:

o Seal rad to core support

o seal shroud to rad

o close the gap between grill and core support at top with beauty panels (this prevents recirculation of hot engine bay air back through condenser/rad combo)
https://www.lmctruck.com/1967-72-che...ller-panel-set

o used rubber sheeting to direct all air being pulled through condenser/rad combo to go through condenser rather than around it: Just cut this and use self tappers to secure:
https://www.summitracing.com/parts/sum-939510

o wired a pusher fan onto the front of the condenser and actuate it via a trinary switch so it comes on only when high side pressure gets to ~250psi.
Not the fan I installed but similar:
https://www.summitracing.com/parts/pro-141-641
Trinary switch:
https://www.summitracing.com/parts/vta-11086-vus

EDIT:
Other improvements: under dash used zip ties to secure, tightly secure the duct tubing to the VA output ports and the dash vents. Getting rid of leaks here equate to better air flow and cooling performance. Spent time ensuring any outside air isn't getting into cab: kick panel vents and door seals.


The pusher fan cycles on usually at idle, keeps high side pressure regulated when necessary and helps the system maintain cooler vent temps at low speed/rpm. This particular pusher is a cheap, 40 dollar unit rated at 1200CFM and 12 amps. Not a good fan for cooling the engine as I learned but perfect for this task.

Doing these things will improve A/C performance but also inject the max amount of condenser heat into the cooling system. That is, any heat that used to just sit in the condenser being bypassed by incoming air will now be pulled through the radiator. Regardless of whether or not you are utilizing electric fans to move the air, doing things this way will put more stress on the cooling system.

After doing all the above except the addition of the pusher fan, my coolant temps would creep at idle on a hot day toward overheat until I turned OFF the A/C. This prompted me to replace my fans with beefier units from spal which solved the creep at idle.

My A/C still required the pusher fan mainly because the condenser, while mounted as close as I could get it to the rad, sits off the radiator by a good 3 inches.

Hth,

-Kevin

[theastronaut]

Nothing wrong with electric fans, all new cars use them and they work. I used a HHR fan/shroud combo on my '66 C10 with a temp switch from a Mercury Capri/Ford Festiva in the upper hose that kicks on at 210 and off at 205, with a 195 thermostat. All oem parts and it's been dead reliable. With AC you'd use a trinary switch to kick the fan on whenever the AC is on to pull air through the condenser in traffic.

Finding an OEM fan/shroud that fits your radiator is a better option than aftermarket fans most of the time. Then seal up any gaps so air isn't going around the radiator or condenser. Another option is a separate fan on the condenser itself, but without a shroud so the fan doesn't block air flow through the radiator when driving.