A/C Condenser question

gt3r · gt3r's Garage

Is it possible to mount a parallel flow condenser horizontally?? I would like to replace the rear tube and fin condenser with a more efficient parallel flow model but I think that they are designed to be mounted vertically. Any thoughts???

Thanks for any input.

Mike

stormcrow · stormcrow's Garage

Shouldn't make any difference. The refrigeration will still flow through it regardless of what position it's in.

Steve

"A Porsche does more then just go fast in a straight line"

scottb · 06-24-2003, 08:12 AM

Mike: Did you ever put in the parallel flow condenser? If so, was it a direct replacement, or did you have to fabricate brackets? Was the a/c any better?

Thanks.

Scott

gt3r · gt3r's Garage

Hi Scott,
I did get the parallel flow condenser (12"x26.5") from ACKits.com and I ended up mounting it in the top of my turbo tail. I had to fabricate the mouting bracket because I did not want to put the weight of the condenser on the fiberglass portion of the intake grates. I am still in the process of changing out the hoses to barrier type so everything is still apart. I'll post a picture tomorrow of the condenser mounted in the tail. BTW I also decided to run a 10" pulling fan on the condenser so I had to modify the decklid to accomodate it. There is room to run (2) 10" fans on the condenser in case the one doesn't dissapate enough heat.

Mike

scottb · 06-27-2003, 12:58 AM

Keep us posted! I'm doing an a/c upgrade at the moment. I'm adding a condenser/fan assembly in the front left fenderwell, and I'm adding a Procooler. I'm considering a parallel condenser for the rear deck, though my sense is that the improvement (if any) from the parallel condenser would be marginal, and that *if* I get any improvement it will be because of the fenderwell condenser.

'Tis the season to play with Porsche a/c, eh?

Cheers!

john hejmanowsk · 06-27-2003, 05:08 AM

OK, first time on the board so consider me a newbie...
Scott, are you putting a 964 front condenser/fan into your '84 or an after market? any problems with fit-up (if its from a 964)? Have you considered using any of the 964 lines to go front and back? And, this will really show my newbie status, what's a Procooler?
Thanks.
John

Thomas Owen · 06-27-2003, 05:29 AM

Scott - where did you get the front condenser? I just ordered the complete 964 assembly from 20th St. Auto in Phoenix, should have it today. My plans are to eliminate the rear condenser and mount the 964 unit in the fender.

John - welcome to the board. The Procooler (do a search) mounts up by the receiver/dryer in the front left fender and works to lower Head Pressure. This, so it seems, improves cooling by varied amounts.
Good luck to you both,

scottb · 06-27-2003, 05:34 AM

John: Welcome to the board! You're going to find it a great source of information. Tell us a bit about your car.

I'm using an aftermarket set-up from www.iceac.com. Bob there says it comes with brackets, and will fit my 84's fenderwell. I didn't want to mess with fabricating brackets or worrying about the fit of a 964 unit. I'm going to retain my rear condenser, so I will have three -- the rear one, and two up front. Both of the condensers up front will have fans on them to increase airflow and heat dissipation.

Go to www.procooler.com to get info on the ProCooler. Also, do a search on the board. It's somewhat controversial, and some people swear by it while others think it's snake oil. I'm going to gamble that it will help. I certainly don't think it will hurt.

john hejmanowsk · 06-27-2003, 06:45 AM

Thomas: I would like to do the 964 condenser, but how hard will it be to fit into a '77? how much rework to the existing fender do you anticipate? fab a couple of brakets, or something more extreme? any welding required? Thanks.

I read the procooler stuff.... seems it would drop the temps at the evaporator but doesn't help get rid of the heat energy in the coolant. If you don't get rid of the system heat energy (via condenser), won't the whole system temp rise? I must be missing something...

gt3r · gt3r's Garage

Here are the pics of the parallel flow condenser.

masraum · 06-27-2003, 07:42 AM

jeez, just wish it wasn't so visible in there, but if you paint it black won't it absorb heat from the sun which will reduce it's efficiency?

Jim Sims · 06-27-2003, 07:50 AM

Pro-cooler is a type of subcooler. It is valid approach; we covered the concept in my engineering thermodynamics course 25 years ago. It is based on absorbing heat with the remaining refrigerant liquid at the outlet of the evaporator. With a very good subcooler the coefficeint of perfromance can be improved by 25 % or so. Some automotive OEM condensers are now being supplied with a built in subcooler. I don't know how good the Pro-cooler is but don't expect it to make up for a poorly maintained system or lousy condenser or evaporator airflow. Cheers, Jim

Thomas Owen · 06-27-2003, 08:12 AM

I am being supplied the brackets from the 964 and on my '88 I am hoping the most I have to do is move the large washer reservoir bottle that is located forward of the tire. I will get back to you once I have some pictures and more info.

john hejmanowsk · 06-27-2003, 08:17 AM

Thermo wasn't my favorite class, but, perhaps I am using now for the first time in,,, ok, ever. Here's the something I think I was missing....

The procooler by itself does not provide additional heat radiation into the atmosphere, only the condenser(s) does that.

If you have adequate, or excess, condenser capacity the procooler will improve your cooling by additionally lowering the temp of the evaporator coil. However, if you have inadequate condenser capacity the procooler will not help.

Ok, this is my first day on the board. I need some additional advise. How do you guys get any work done?

Hladun · 06-27-2003, 02:05 PM

Whatever type of condenser gt3r uses is not as relevant as the pancake fan he's got under the condenser (pictures). The big problem with rear decklid condensers is that the airflow through them is too low. The engine fan looks nice, but it doesn’t move much air. I have 78SC with ONLY a decklid condenser running R134a, but with a fan I get <45F vent exit temperatures.

gt3r · gt3r's Garage

Hey Hladun, do you think I can get rid of the front condenser and still achieve the same cooling, or maybe add an additional fan on the rear condenser to compensate? It would save me some additional hose and routing if I could ditch the front condenser. How efficient is the front one? someone said that with the parallel flow condenser, the additional front one would only act as a subcooler. Does the temperature of the liquid refrigerant make a difference in the overall cooling or is it enough that it is in liquid form. BTW some say that preheating the air through the condenser is bad for the engine but the factory mounted the stock condenser in the same spot! Anyway I wouldn't think that my condenser would heat the air any more than an intercooler and condenser with fan on a turbo would. Thanks for any input.

nostatic · nostatic's Garage

I guess I"m on the bandwagon too. Took the car to have the AC charged and the good news is it holds a vacuum. The bad news is it couldn't charge, so either the compressor is shot (not mixing?), receiver is clogged, line is crimped, or ? I'm going to have him replace the York with a rotary and put in a new receiver/dryer and expansion valve. We'll see what happens after that...

jdowty3 · jdowty3's Garage

Hey GT3R, the 993 uses the same fender condenser and have no front condenser, so you can get rid of the front if you want to.
The real trick in 911 AC is keeping the Freon temp as low as possible so it stays in a liquid state before it hits the expansion valve at the condenser. As it passes through the expansion valve, it expands, turns in to a gas as it heats up, thus pulling heat out the air passing through the evaporator. If the Freon gets hot enough before the expansion valve, it dramatically reduces the efficiency of the system. The Freon tends to either not cool enough (not enough condenser and/or air flow) or it heats back up as it passes through the 16+ feet of hose between the rear condenser, the front condenser, and the receiver/drier. The stock receiver/drier gets really hot just from ambient road heat and it is not insulated. The Procooler works by having an outer chamber around the receiver/drier chamber and replaces the stock reciver/drier. The Freon coming out of the evaporator still has some in liquid form and when it hits the Procooler outer chamber, it expands to a gas, the outer chamber get cold just like the evaporator and helps to keep the inner chamber cool. The result should be all liquid Freon to the expansion valve and a more efficient AC system. Sorry for the long explanation.
No monetary interest, just a satisfied customer

GSpreeman · GSpreeman's Garage

How often should I recharge the AC with freon?

jdowty3 · jdowty3's Garage

Only when it's low. The receiver/drier sight glass and/or a pressure guage should give you an idea of when the level is right. It's a sensitive balance. Obviously, too low is a problem, but too much can be almost as bad. One guy I know added a little more to a newly recharged system and caused a problem with the expansion valve. Replacing the valve means haveing the evac the system again and a complete recharge.