Adding AC condenser and Procooler

[Guy Chiattello]

I am replacing the decklid on my 1982 Porsche 911SC with a 91 C2 deck lid with an electric spoiler. This means I will loose the condenser on the rear deck lid. I am installing a small Honda civic condenser in the driver side rear wheel-well and a Universal Parallel Flow Condensers under the bottom of the car. This one will not have a fan but the one in the wheel-well will have a "pusher" fan.

Should the condenser under the car without the fan (which means when the car is not moving there will not be much airflow) be first in the series of three condensers or last?

I also intend to add a "Procooler" Drier accumulator combination that's made specifically for the earlier model Porsches. Anyone have a negative report on these? The results posted on their web page seem impressive.

Another question is: By adding additional condensers and hose length will I over tax the system? One of the attributes of the "Procooler" is that it is supposed to lower head pressure about 100 PSI. I don't really know what that means and what implications it has for what I am attempting. Can you help me.

[scottb]

Do a search for "Procooler." There's been plenty of discussion on the board about it, and there's something of a split opinion on how well it works.

It sounds like you're essentially copying Griffiths' Kuehl Condensor for the rear wheelwell. Go to www.griffiths.com if you'd like to see what Charlie does. He has a guard to protect the condenser from road debris kicking up and damaging the condenser. My assumption is that you'll wire the condenser fan into the compressor circuit so that when the compressor is on the condenser fan is on.

Performance Aire here in Orange County sells an under-car condenser. They've got theirs set up to protect the unit from road hazards, though it still can take a direct hit. www.scottsind.com.

On the subject of where in line the new condenser should be, I 'm sure you'll get some responses. Jack Olsen, Joeaksa and Targa22 are very knowledgeable about Porsche a/c.

Once you get the project done, post a note and let us know how it turns out. Good luck with it!

Scott

[Guy Chiattello]

Scott,

Thanks for the feedback. I'll check out some of the sites you posted.

guy

[Hladun]

I'd suggest the underbody condenser be first in the series. The difference is probably not large, but the a/c fluid would be hotter in the first condenser and a larger temperature difference to ambient would result in better convective heat rejection. The fan cooled condenser should be able to bring the a/c fluid closer to ambient temperature than convective cooling.

Remember to keep a/c hoses away from hot oil lines and exhaust components.

I don’t use it, but I think the Procooler can help as it raises the compressor inlet, hence outlet, temperature and this should give better heat rejection in the condensers. The Procooler then drops the charge temperature just as it goes to the evaporator. On the basis of “the more heat you can reject results in better cooling” this device should therefore help.