Air Conditioning System
System Components
There are six basic components that comprise the air conditioning system: the compressor, the condenser, the evaporator, the drier, hoses and fittings, and a safety switch. All these components must be carefully selected if the system is to perform optimally.
For those who lack a technical knowledge of how the AC system works, I'll give you a short explanation.
Beginning with the compressor, it pumps the refrigerant, in gas form, into the high pressure gas discharge line. This gas is loaded with heat it has absorbed from the air flowing across the ecaporator coil located in the passenger compartment. As the heated high pressure gas reaches the condenser, the heat is carried off by the air flowing through the condenser. The gas becomes a liquid and the pressure drops. It then passes through the drier. Air is purged and the liquid then flows to the evaporator where it passes through a coil. As air flows through the evaporator coil, cold air is blown into the vehicle and the cycle starts over again.
My System
I am using components from Vintage Air. Vintage Air has been in the business of making high performance air conditioning systems since 1976.
I bought a Vintage Air air conditioning system (Mini Gen II, P/N 66005-VUZ-A) with AC, heat and defrost. Many of the GT40 owners I spoke with said the heat portion isn't really needed unless you live in the north east. So, my plan is to use just the AC and the defrost.
Here is the AC mocked up with jack stands. I wanted to center the unit, but it interferes with access to the pedals. It looks like I have to push it all the way to the left....
The evaporator measures 7.3" tall, 19" wide, and 9" deep. The kit comes with AC and defrost ducting, vents, wiring, relays, and hardware. Because the RCR GT40 chassis replicates the original monocoque chassis with the tire well, fitting the AC system in the car is...A CHALLENGE!!
I followed the instructions by installing the ducts to the unit, then placing the unit on a floor jack inside the car. I then raised the unit as high as it would go, marked the hole locations, removed the unit, drilled the holes, then installed the unit with the included hardware. WHEW!! All this took the better part of one day doing the work alone. It would be far easier if I had one or two friends helping.
After I installed the evaporator, I discovered that I won't be able to use the defrost option because of interference. Oh well.
Two types of vents come with the kit - eyeball style similar to the type on original GT40s and various louver styles found in most modern production cars. I installed the eyeball style in my dash and feel it looks pretty damn good.
The drier I selected is the chrome unit with a trinary safety switch built in (P/N 07309-VUQ). The trinary safety switch encompasses low pressure and high pressure compressor clutch cutoff functions and electric fan engagement signal at 220 psi.
The condenser is a Vintage Air universal unit (03704-OVA). It measures 20" wide by 12" tall. It's equipped with a #8 inlet fitting and a #6 outlet fitting o the bottom. Installation was pretty straight forward. I did have to fabricate some lower mounting brackets.
A close up of the lower mounting brackets made from .040 6061 aluminum
Fresh Air Ventilation
The windows in a GT40 are fixed in place - they do not roll down. They do have a small flap window that opens to provide some air, but for a raod car, AC is a must. The problem with this setup is that the AC must be run nearly all the time while driving. This didn't seem to be ideal to me, so I decided to develop a freash air system that could be used when AC is not needed. This fresh air system can be turned off, allowing the driver and passenger the option of AC, blended AC and outside air, outside air, or nothing at all.
The system uses the original small NACA ducts on the front clip and directs outside air to the cabin like the originals. Where my system differes is the vents can be opened and closed with cables located near the dash pillars. The ducting is attached to the AC ducting with "Y" adators then attached to the dash eyeball vents. A pair of lawnmower push-pull throttle cables open and close the ducts, which are 2-1/2" plastic woodworking blast gates.
The underside of the front cabin access panels shows the plastic blast gates attached and the fresh air ducting attached. The ducting attaches to “Y” adaptors that allow the use of AC, blended AC/fresh air, or just fresh air
The system installed. The ducts connect to the small NACA ducts on the front clip.
I fabricated a couple of brackets in the cockpit to mount the vent cables.
