Cheap air conditioning mod

OK Guys and Gals,

Here is a good weekend afternoon project for you if you live in warm areas.

We all know that the key to keeping your air conditioning working and blowing cool air (after making sure that your freon stays inside the system and everything else is up to snuff) is keeping air flowing over the front and rear condensor, this keeping cool air flowing out into the cockpit of the car. Porsche put a electric fan to blow air over the front one however nothing in the back.

At idle the only air flowing through the aft condensor is what little is pulled through the unit from the engine fan, which is not very much.

I was at one of our local electronic stores (Dallas area, AlTex in Carrollton) and saw
something that gave me an idea. They had some "pancake" type fans, that were one inch (more
or less) thick and around six inches in diameter. 12 volt and 500 mA for $9.95. These
appeared just the right size to mount on the underside of the condensor inside the engine
compartment and pull air past the unit all the time, thus keeping the unit cooler, especially when sitting in traffic.

Took a chance and brought them home and they fit like a charm, with enough room to clear
all the important bits inside and still provide a good amount of airflow. Mounting was a problem then the light came on inside my feeble brain. I took four black heavy duty wire ties and inserted them from the outside of the grill in the direction of the motor, and stuck their ends through the mounting holes in the fans. Took another wire tie end and secured them against the condensor.... they are not going anywhere and the plastic wire tie will not do any damage to the aluminum fins either. The "heads" of the wire ties pull against the outside fins of the condensor and should do no damage here either.

Mounted the ground wire to the chassis and the positive wire into the power wire going to the air conditioning clutch. This way when the AC compressor comes on the fans will as
well, with a minimum of wiring and hassle. They draw together just around one amp and this system should be able to handle it. If not I will put a relay in and trigger it off of the compressor clutch.

Started the car and the difference at idle was noticable. Should be the same or better
while sitting in traffic. For right around $20 this mod should make the car much more
liveable in the summer heat. You should be able to find fans like this in almost any good general electronic store.

Will report back in a few days on how its doing.

JA

Joeaksa,

Sounds just like what I've been looking for. Did you use 2 or three. Do you think they will withstand the heat back there and what are your temp changes on your year model. What do you think they were to be used on. Whats there phone#? and are they open on Sun?

Mike Miller
89 911
Arlington, TX.

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Joe
Let us know the results after a little more testing
My concern is, I noticed that my front fan I installed for my carrera cooler works against it at highway speeds by reducing air flow though it doesn't seem like the rear deck would get as much air at highway speeds so this may not be a problem

Mike,

AlTex is located on the SW corner of Midway and Trinity Mills, but set back in so that its easier to run to the stoplight just South of TM and turn West, then you see it inset behind a auto repair shop. 972 386 8882

They are pretty much computer and electronic nuts there but have other stuff as well. These fans I assume were made for cooling a computer housing of some sort. They had lots of the 4" fans and less of the 6" versions. There was one or two left after I purchased mine but I would believe that they can order more.

I used two of them on my installation and feel that I had room for one more there. The problem lies with clearing the fuel injection and air filter bits and pieces inside the motor area.

As far as the heat issue in the engine compartment, I feel that the air coming into the area should help cool the fans and even if I lose one or two a year, its only $9.95 a piece, a bargain as Porsche parts normally go.

As Mike will tell you, sitting in traffic in the summer around her kills you and the AC loses much of its effectivity. I hope that this will help a bit until you are able to get moving again.

Will keep everyone informed on how it does. Mike, if you need more info, email me and I will get you my phone number.

JA

jryerson,

Forgot, the fan pulls the air inside the engine compartment, the same direction as the fan on the engine. These simply assist the airflow through the condensor when the fan on the motor is at low speeds due to idling in traffic.

I agree that the fan in the front seems to be working against the natural flow once driving, but these additional fans will assist the flow at all times and hopefully not block any airflow when they are not turned on the 9 months of the year we live with the AC turned on.

JoeA

Hi joe
Let me clairify,I wasnt concerned with the fans but the engine temp, the fan for my Carrera cooler makes a great difference stuck in traffic but if I have it on at highway speeds it acually works against the air flow and my temps are much hotter unless I turn it off

keep us posted
Regards
Jeff

Jeff,

Thanks... misunderstood. Actually I was looking for a fan for my cooler like you have then the light bulb went off in my head to use one or more of these to increase the airflow on the condensor.

Will get another one for the oil cooler. Mine is a 85 model so no fan or switch, so it will have to be a manual unit.

Take care,

Joe A

Joe,
How much of a difference in temperature do you notice coming out of the a/c vent?

Thanks,
David88911

Hi Joe - -
-
Intested to know if the fans are rated for high temp and wet applications. Rain and wash water is going to get the fans wet, for sure. And engine compartment temps can create a very hostile environment for equipment that is not designed or built for it.
-
Chuck

What year, if any, did Porsche start adding a fan to the front fender mounted oil cooler?

Leland - -
-
The fender mount oil cooler fan was added in 1987 through 89. With it, the cooler itself was modified for the temperature switch. Those of us with 84 - 86 coolers just run a manual switch for the fan. Easier to wire and better control over temps.
-
Chuck

After two days driving in the heat, the fans do make a difference in stop and go traffic. For the $20 I spent it is well worth it as I actually had to turn the temp control down (was getting too cold) today and I usually keep it at the max all the time here in Dallas.

As for the comment on the rain and heat having an effect on the fans, I do not feel that they will have any problem with the heat, as they were designed to work in a hot area from day one, and pull cooler air inside. As for moisture, ask me in a few months... I have no idea but with my costs involved am not worried about it. Considering the costs I can replace them every year and still be ahead.

Will keep everyone posted...

JA

Joe,

I must say, I agree with your poists. If you want some hard data numbers.. look at my post "cooler Carrera". I wouldn't trade my fans for twice the price.

Scott,

Thanks and I had already looked at your mod and posts. I do not feel that the heat is that big of a problem at this time in my car but your mods look interesting.

I have worked with four and six cylinder air cooled aircraft engines for years and the only fan they have on the ground is the little air pushed in the cowling from the prop at idle, which is very little. We have little damage due to heat, althought the application is different. Warren has a good point that it is not good to cool the motor too much either.

Thanks for your info on the temp readings. I am surprised like you were that the heads started cooling down so rapidly...

The two fans are working fine on mine and hope yours do as well. My main worry with the time delay switch on yours is that it would stick on and drain the battery. Mine cuts off when the AC clutch does and that is enough for me... until you get some miles under your belt, I would stick my head out 2 minutes after turning the car off just in case... too much PFM here and you never know.

Thanks,

JA

are these big versions of the "muffin" fans that cool computer power supplies? Or some other type of fan? Is it possible to post a picture or email one? thanks

John,

You are correct but they are a lot bigger. Mine are 6" around and just at an inch thick.

JA