I've been lurking on here for a while, but haven't jumped into the fray until now. I'll chime in on this since I've had an AC cooler on my truck for about 4 or 5 years. My setup isn't nearly as complex or efficient as this one, but it will give you an idea of what to expect. I'll also throw out what I have been planning to do that will work just as well as the cooler in this thread, but be nearly free and not require tapping into the stock AC system.
The first thing I'll talk about is track and dyno results since that is what everyone wants to know. IIRC, on the dyno I saw a gain of 2 rwhp with my setup, which isn't even enough to qualify as a measured gain. However, I was able to make several runs without power dropping off which I could not do before. These results were mirrored on the track. I made 5 passes back to back without the cooler on and then 5 passes with it on. Without the cooler I lost a tenth or two on each of the first three passes before bottoming out. I don't remember what the times were, but I believe it dropped from around 13.60 to about 14.1 over the 5 passes. I do remember that I ran within a tenth of 13.7 on each of the passes with the cooler on. It absolutely does something, the only question is how much. BTW, it was between 90 and 95 degrees when I did the test.
As for running the AC at the track, they will probably throw a fit. They did for me. Unfortunately, the condensation that your AC generates is at its peak at the same time you need you AC cooler working the most. When running at capacity, the AC will run an almost steady stream of water onto the track. It is considerably more than someone tracking water to the line on their tires from driving through the water.
Another benefit of this system is that the load of the AC will soften the throttle response at the starting line. If you have a high powered vehicle with poor traction that can make driving a lot easier. The AC will cut off when you hit WOT, so it won't cost you power down track.
The compressor won't know the difference bewteen the stock system and this. It is the same compressor used in the Expidition which is available with dual AC systems. It won't see any more load in this application than it does in the Expy. This is a non issue.
Why would you need a refrigerant capable of handling higher heat? In the heat of summer it is not uncommon for r-134a to operate in excess of 400 psi. It's not good when it happens, but it does. A quick and dirty application of the ideal gas law will show you that the temp of the refrigerant as a superheated vapor at 400 psi wil be much higher than it will ever be in the induction tract of the engine. Even in an adiabatic compression it would probably be close to 200 degrees. Throw in a little inefficiency and 300-400 degrees isn't unreasonable.
On a road course I doubt you would get much performance benefit from this, but you would give yourself a little insurance against detonation. My AC blows nice and cold on the track, so it would definitely do enough to keep the IC chilled.
If you want to experiment with this on your own without dumping several hundred bucks into it there is a much easier way. All you have to do is reroute your IC hoses through the heater core and turn you HVAC controls to defrost. The compressor runs in defrost mode, so the AC system is providing cold air. When the air comes into the cab in defrost mode it goes over the evaporator first and is chilled. If then flows over the heater core, so you are blowing 25-30 degree air over a fairly efficient heat exchanger that has your IC fluid in it. If you are really ambitious you could even plum the heater control valve from an Explorer into the system so your heater and IC would function normally when not under boost.
Edit to add:
You can handle 134a legally yourself unless there is a local law against it. As far as the feds are concerned any shmuck off the street can by 134a, walk out in the parking lot and vent it to the atmosphere. You only have to be licensed to handle 134a if you are doing it for hire.
The first thing I'll talk about is track and dyno results since that is what everyone wants to know. IIRC, on the dyno I saw a gain of 2 rwhp with my setup, which isn't even enough to qualify as a measured gain. However, I was able to make several runs without power dropping off which I could not do before. These results were mirrored on the track. I made 5 passes back to back without the cooler on and then 5 passes with it on. Without the cooler I lost a tenth or two on each of the first three passes before bottoming out. I don't remember what the times were, but I believe it dropped from around 13.60 to about 14.1 over the 5 passes. I do remember that I ran within a tenth of 13.7 on each of the passes with the cooler on. It absolutely does something, the only question is how much. BTW, it was between 90 and 95 degrees when I did the test.
As for running the AC at the track, they will probably throw a fit. They did for me. Unfortunately, the condensation that your AC generates is at its peak at the same time you need you AC cooler working the most. When running at capacity, the AC will run an almost steady stream of water onto the track. It is considerably more than someone tracking water to the line on their tires from driving through the water.
Another benefit of this system is that the load of the AC will soften the throttle response at the starting line. If you have a high powered vehicle with poor traction that can make driving a lot easier. The AC will cut off when you hit WOT, so it won't cost you power down track.
The compressor won't know the difference bewteen the stock system and this. It is the same compressor used in the Expidition which is available with dual AC systems. It won't see any more load in this application than it does in the Expy. This is a non issue.
Why would you need a refrigerant capable of handling higher heat? In the heat of summer it is not uncommon for r-134a to operate in excess of 400 psi. It's not good when it happens, but it does. A quick and dirty application of the ideal gas law will show you that the temp of the refrigerant as a superheated vapor at 400 psi wil be much higher than it will ever be in the induction tract of the engine. Even in an adiabatic compression it would probably be close to 200 degrees. Throw in a little inefficiency and 300-400 degrees isn't unreasonable.
On a road course I doubt you would get much performance benefit from this, but you would give yourself a little insurance against detonation. My AC blows nice and cold on the track, so it would definitely do enough to keep the IC chilled.
If you want to experiment with this on your own without dumping several hundred bucks into it there is a much easier way. All you have to do is reroute your IC hoses through the heater core and turn you HVAC controls to defrost. The compressor runs in defrost mode, so the AC system is providing cold air. When the air comes into the cab in defrost mode it goes over the evaporator first and is chilled. If then flows over the heater core, so you are blowing 25-30 degree air over a fairly efficient heat exchanger that has your IC fluid in it. If you are really ambitious you could even plum the heater control valve from an Explorer into the system so your heater and IC would function normally when not under boost.
Edit to add:
You can handle 134a legally yourself unless there is a local law against it. As far as the feds are concerned any shmuck off the street can by 134a, walk out in the parking lot and vent it to the atmosphere. You only have to be licensed to handle 134a if you are doing it for hire.
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