piranhaman

Having installed a lot of air conditioning systems in hot rods and vintage Mustangs, the problem isn't with the condenser, its with the evaporator. Specifically, the evaporator coil just isn't big enough for the car. Has anyone ever seen the condenser on a vintage Mustang (65/66), or any other small compact car? They are extremely small; yet they're A/C systems work great. For example, a 65/66 Mustang had a huge underdash evaporator unit. It would literally take the car down to 40 degree in the summer. The 67/68 Mustangs went to a built in evaporator, which was half the size of the underdash unit. As a result, the system could barely cool the car; yet they both used the same size condenser. Another factor is R-12 verses R-134a. Any reputable A/C shop, not a general mechanic shop, but people who only specialize in A/C systems will tell you R-12 is far more efficient and cools better than R-134a. Needless to say, switching to R-134a from R-12 is only making the problem worse. Adding a bigger, larger volume fan isn't going to help either. If the evaporator coil isn't big enough to start with, then all you are doing is pushing more half cold air out, which is a false indication the system is working better. If your car has a piston compressor, then change it to a rotary compressor like a Nippondenso. Piston compressors are very inefficient, noisy and most of all, eat a lot of horse power! If your car's A/C system has been thoroughly checked for leaks by professionals, charged properly (over charging the system will actually reduces cooling capacity), still isn't performing like you want it too, then increase the size of the evaporator coil. The photo the car with the huge condenser mounted on the pan underneath the car is nothing more than a disaster waiting to happen. A condenser needs air moving "through" it, not around it!

edpurplett

my condendser is a disaster waiting to happen?..... no need to be rude?.. I also have had 5 911's and this is the ONLY one that creates air 45-55 degrees below ambient...

I dunno... there are over 50 kits with my condenser running around... whatever...

piranhaman

Sorry, my comment was not meant to be rude or malicious, my appologies!

Sameer

John,
How'd it go with the AC?

911rudy

IMHO, I disagree with fishman on the cause of poor cooling in the 911/930. The condenser is where the liquid freon is cooled before passing through the evaporator. If the fluid is hot then when it does evaporate and absorbs heat in the evaporator the temp drop is not very great. The evaporator in the Pcars is not serpentine and is a poor choice but it will cool if the freon is cooled. On the old Mustangs etc, you must remember there is always a big engine fan pulling outside air accross the condenser. That is why you can use a small serpentine evaporator. The 911 front condenser has almost no air flow and in my opinion, the air flow that it does have goes the wrong way. It should be pulling the air accross, not blowing it into the incoming airstream. Bottom line; replace both the front condenser and the evaporator and add the extra condenser in the rear wheel well. The comp is fine, (Rotary only).
Sweating Rudy

Jastx

Sameer,

I just bought a kit this past weekend from Rock at Retro-Aire. I found he is just a short drive from my home, so I got to meet him in person and see everything. Griffiths and Rennaire also sell great products but the local presence means a lot to me. In the kit, I got a parellel flow condenser for the rear, a serpentine evaporator, barrier hoses, drier with hi/lo switch, o-rings, o-ring oil and some misc stuff. I will start the changeover in a week or so and take a bunch of pics.

911rudy

John,
You have broken the code on getting things done. Local is always better than internet because of the obvious reasons. Good luck with the conversion and let us know what happens.
Rudy

im4duke

What did your kit cost, John?

Jastx

im4duke,

Info on the kit I bought is here: http://retroair.com/. Obviously, click the Porsche link.

I see you are in Dallas. PM me and we can get together and I 'll show you this stuff.

im4duke

Thanks, John. PM sent.

Martin Arias

Hi,
While this may not seem high tech, I bought a few cans of a/c sealer, conditioner and refill this summer with a self install kit at Pep boys and it worked miracles this summer in humid and hot Philadelphia. The a/c output went from hot to approx 40 degrees. Cost - $50. Perhaps you just need to refill more often. By the way, I filled it up just short of the red (danger) zone in the gauge to get this system to crank. In my previous refill, the ac did not work as well because it did not have the right pressure. These are just unscientific observations and I do not recommend you do this at home.

Jastx

Martin,

Please tell me more. What are these products at Pep Boys, especially AC sealer? Is this R12 or R134? Do you have your own gauges or is there some kind of gauge with these products?

Finally, where were you two months ago when I was sweating my buns off in 100+ degrees?

Martin Arias

Jastx,
Yes I bought a self install kit with a handy gauge (to keep you from blowing up your ac) and bought a couple of cans of a sealer, conditioner and R134a refill. Just go into any auto parts place and I'm sure they have something like it. I think the product was called cool fill or cool something. Originally I had a dealer refill my ac, but it didn't work very well. After researching the problems with 930 a/c' s I came across a post that suggested that R134 needed slightly higher pressure to run in old converted r12 systems. Thus, before spending mucho dinero on compressors, new lines, etc, I thought I would give it a try. However, be very careful, this stuff can freeze your fingers off if exposed to it.

Martin
Triple Black 930 Cabriolet