I remember reading a post awhile back from someone who installed a second AC condenser. I am looking to do the same thing and was wondering what the sizes are of the hose fittings that I need to have made up.

Any help would be greatly appreciated...

 

Why a second one?

 

Hello,

I'm planning to add a back condenser too...

In my country, Lebanon, Temp reaches sometimes in summer 100.4F about 40 C, But inside my 993 C2 1995 the AC is not close to what excpected from other cheaper cars and yet less sofisticated. I have anylised the whole circuit, pressure Hgh & Low, Have changed the Drier, changed also the refrigerant to R12 again, BUT the result stayed the same!!!!!!!!!!


I wonder what the arabic countries do, such UAE, Saudia and around...???

By the way this is what i hate in my Porsche

 

Since the condenser is simply a heat exchanger, increaseing the surface area will improve the AC systems efficiency...Similar concept to adding additional engine oil coolers.

Anyone able to help with the fitting sizes?

 

See the Mr. Ice Project site that had amazing results with a 911:

http://www.griffiths.com/porsche/ac/ice/index.html

 

Sorry, can't help with the fitting sizes. But I do have some considerations concerning a second condenser.

Adding a second condenser will only help if the first condenser was incorrectly sized (possible) or it's not doing its job (clogged or maybe the fan isn't working).

The condenser's job is to remove enough heat from the refrigerant so that it condenses into a liquid (before the condenser it is a high pressure gas). As such, the condenser can only remove heat until it reaches the saturation curve (intersection of red and green lines on chart). To remove more heat would require "subcooling" the refrigerant (which is now liquid). Unfortunately, this is not possible with an air cooled condenser (in dry climates, a mist of water sprayed on the condenser would achieve some amount of subcooling). One downside of this subcooling is that the compressor will have to work harder and its longevity may suffer.

If you do add a second condenser, let us know how it works.

 

Has ane aniyone tried HC12A refrigerant in air cooled cars? It has much better cooling capabilities and I have improved my AC in the Boxster and my 90 Miata. It is a direct replacement for RC12 or 134A. The hype is really true. I have seen a remarkable difference in the Atlanta summer heat. The auto mode in Boxster never slowed down in the heat of the day. With HC12A it cuts down within 5 miles of home to about half speed or less and stays cool. I would love to know if it makes a difference in air cooled 911s.

 

Now that's an AC system. Any idea on the cost?

 

Just my 2 cents here, but would'nt it be good to put some Good insulation around the aluminum tube runnig along the left flank from the condenser to the compressor. My tubes are just naked under the plastic cover!

 

I'm no AC expert but I'll speak up anyway.

There are two pipes under the left sill. One is the high pressure pipe from the compressor to the condenser. This pipe will be hot as it contains the compressed freon. So no point in insulating it; any heat which it dissapates before getting to the condenser is a good thing.

The second pipe is the (relatively) uncompressed freon after it's gone through the evaporater (and hopefully cooled off the inside of the car). I suspect that it wouldn't be a bad thing if this pipe were insulated so that the freon that gets to the compressor is as cold as possible to increase the system's efficiency.

I recently replaced my condenser after a leak. I was amazed at the amount of small rubbish clogging the fins and the leaves and the road litter (like pieces of foil from crisp/chips bags) in the duct. Oh, and the small dead bird too.

My advice would be to make sure the condenser is truly clean and that the fan resistor is OK. If that still isn't good enough for your ambient temps then more drastic steps might be required.

 

On our way from MS to Sebring for the PBOC event , my friend and Porsche mechanic said : " I thought I would never say this while riding a 911 but this air is too cold, turn it down ! " Moral of the story , the A/C in the 993 works fine in South Mississippi Summer weather without help . If I remember correctly , as part of the pre-launch testing for the 993 , the engineers took the cars to all severe climate areas an assessed the HVAC's capabilities . In my humble opinion, they got it right this time . Having owned a 78 SC , 86 Carrera , 91 C2 Cab and 90 944 S2 , the 993's is the best system . As said many times before , check the basics first before trying to improve on the factory design .

 

Thanks Phelix. You're right, the insulation should only be around the "cold" line. I put this and the cleaning of the condenser + check of the resistor on the "to do" list for next winter.

 

Ken (deltawedge) is absolutely correct. An additional condenser will not "cool" anything if the refrigerant (R134, R12, whatever) is already condensed back into its liquid state. It is NOT like an oil cooler where additional exposure reduces temperature via heat exchange. Additional condensers were a fix on pre-964 911s because those condensers were, indeed, inadequate in terms of size/airflow. So when that issue was resolved via aftermarket solutions, the rest of the OE system could do its job and cool the cabin. But since Porsche moved the condenser up to the front fender, right in the air stream and made it a considerable size, a/c went from ****-poor to genuinely cool (albeit still not as efficient as any "normal" car where the condenser is right out in front of the radiator so is ALWAYS getting full airflow, and the lines are short because the compressor isn't at the other end of the car). I'd guess, too, that something else is wrong if a 993 ac isn't cooling adequately. FWIW, I'm in SoCal where summer temps regularly reach the 90s, with stints into the 100s (like this past two weeks ...ugh!). Sure the ac takes longer to shed cabin heat than it would at 85 degrees, but my 993 still gets cold enough where I have to turn it down, even at those elevated temps. Sorry I don't know enough about our specific system to help you out. But maybe you can try doing a search for Randall as he knows the cc system pretty well. Hope this helps.

Edward