Dual 993 a/c condenser system

[Pazuzu]

I was asked to document this, so I will.

I am rebuilding my A/C system (AGAIN!) and will going down a new route. I am removing the 2 factory condensers and replacing them with 2 993 condensers and fans in the fenders. I don't know if anyone has ever done 2 of these before??

History: Previous owner had a system with an underbelly condenser, updated compressor and R12. Was ice cold when I bought the car, but an under hood mistake led to complete freon loss, which stayed that way for years. Fast forward to last year, when I decided to get things cold again. Rebuilt all of the lines with new barrier hoses, full r134 conversion, routed things so that the underbelly condenser was the primary one. All said and done, it worked great, but I only had a few weeks of hot weather at the end of the season.
Since then, I have ripped the underbelly condenser off on a particularly high speed bump, which puts me back to square one.

I wouldn't have spent the money on one of the underbelly units, and won't spend the money on something like the Griffiths addition. Since I can make my own hoses, I can route and change as I want. I decided to stand on the shoulders of giants, and go with a fender system.

The 993 condenser, as we all know know, is amazingly cheap and efficient. $99 from our host, and then $50-75 for a fan. They fit in both the rear of the rear wheelwell, and with some work, the front of the front wheelwell. Serpentine design, very compact...

It's well established how to cram one of these into each location:
Front: http://forums.pelicanparts.com/porsche-911-technical-forum/314087-993-condenser-911-anyone-complete.html
Front: http://forums.pelicanparts.com/porsche-911-technical-forum/224841-993-fender-condenser-early-car-need-help.html
Rear: http://forums.pelicanparts.com/porsche-911-technical-forum/522646-retrofit-993-ac-condenser.html
REar: http://forums.pelicanparts.com/porsche-911-technical-forum/870573-another-boring-ac-thread-installing-993-condenser-3-2-carrera.html
Among others. However, each case has been adding a single 993 part to an existing system. I don't know of anyone running dual 993 parts.

[Pazuzu]

I went ahead and purchased 2 993 condensers from our host (993-573-011-02-M6)
$99 Behr part, currently out of stock
I also purchased 2 different fans, to decide which I liked more. First was a 10 inch straight blade pusher from Spal (30100374), and the other was a 10 inch curved blade puller from Spal (30100435). $65-70 each on Amazon. Why Spal? Because they are common on Amazon, are a known good brand, and surprisingly not any more expensive than other no-name brands.

I actually will use both. The pusher will be mounted outboard of the condenser in the rear, to push the hot air away from the assembly from the headers. The puller will be mounted inboard of the condenser in the front, to pull fresh air from under the bumper.

10 inch spal fans fit perfectly. They have a slight flat on 2 sides which fits exactly in the bounds of the 993 condensers.

Strap a fan on each condenser, and get ready for ice town baby!

[Pazuzu]

Here are some dimensions for those that might want to roll their own...

Bare 993 condenser, with low profile Spal fan mounted. Working outer dimensions given.




Very small indeed!



Future plans:
I need to mount these guys, obviously. I will run the serpentine lines horizontally. Some people have done it each way, but there is room. I have enough hose from my last system to put this together, but I'll need to order 2 or 3 fittings once I finalize things. I might put a compact dryer someone else (maybe mounted on the front condenser?).


No, why did I not put this in the front of the rear wheelwell? Doesn't seem to fit. MAYBE with some playing around with the fan location relative to the condenser, but I didn't feel like putting that much design work in. I know that both the Duel Keuhl and the Zimms front mounted condensers are some special ultra small design, the torsion bar assembly gets in the way of this one.

[Casey at Pelican Parts]

Wow that looks pretty slick! I'd like to see the end result in the car!

[wwest]

Mike,

Assuming your car uses a catalytic converter, may I ever so kindly suggest that you use an IR thermometer (~$30, HF) to measure the outside(***) surface temperature of the rear "fender" before and after a "casual" 5 mile drive. Mine went from ambient, 83F, to 140F with just a short drive.

*** 140F was the average of 5 measurements taken at different points on the fender.

[Corvus Corvax]

Originally Posted by Pazuzu

Future plans:
I need to mount these guys, obviously. I will run the serpentine lines horizontally. Some people have done it each way, but there is room. I have enough hose from my last system to put this together, but I'll need to order 2 or 3 fittings once I finalize things. I might put a compact dryer someone else (maybe mounted on the front condenser?).


No, why did I not put this in the front of the rear wheelwell? Doesn't seem to fit. MAYBE with some playing around with the fan location relative to the condenser, but I didn't feel like putting that much design work in. I know that both the Duel Keuhl and the Zimms front mounted condensers are some special ultra small design, the torsion bar assembly gets in the way of this one.

Nice. BTW, pay no attention to anyone who claims that radiant heat sources like the roadway or the catcon make any difference to the system. Especially on setups where there is a fan in operation. Especially folks who take their cars, measure the initial temperature in the shade, then expose the metal to a giant, glowing thermonuclear source 9.3x10^7 miles away and claim that somehow the catcon made the metal hot. If you really want better efficiency from your condenser, operate it in the shade, and not in direct sunlight.

Make sure you take a lot of pics with your install. I am still considering eliminating the decklid condenser, and need photographic evidence that this is a good idea.

[Pazuzu]

Originally Posted by wwest

Mike,

Assuming your car uses a catalytic converter, may I ever so kindly suggest that you use an IR thermometer (~$30, HF) to measure the outside(***) surface temperature of the rear "fender" before and after a "casual" 5 mile drive. Mine went from ambient, 83F, to 140F with just a short drive.

*** 140F was the average of 5 measurements taken at different points on the fender.

Um...no.

First, I have headers which I mentioned in the beginning. Second, there is many many inches between the headers and the condenser surface. Third, there is a pusher fan blowing through the condenser towards the header, which will stave off convective heating.

[Pazuzu]

Apparently I was stupid, and forgot to add these pics...
Front wheelwell:


Rear Wheelwell:


I'm working off the assumption that we all know that the giant windshield washer bottle needs to GO for this to work. Once that is moved out and replaced or deleted, then there is all sorts of room up front, and that area has lots of airflow from around and under the bumper.`

[wwest]

Originally Posted by Pazuzu

Um...no.

First, I have headers which I mentioned in the beginning. Second, there is many many inches between the headers and the condenser surface. Third, there is a pusher fan blowing through the condenser towards the header, which will stave off convective heating.

Without taking actual IR measurements it's entirely possible that the cooling fan forced air movement is only partially compensating for the IR effects of the headers/engine heat.

[Pazuzu]

Originally Posted by wwest

Without taking actual IR measurements it's entirely possible that the cooling fan forced air movement is only partially compensating for the IR effects of the headers/engine heat.

No it's not. I did a finite element analysis of the car, this is the optimal place to put the condenser. I did however have to take it and put a 15 degree bend in it to fit deeper in the fenderwell, that was not hard with my bench vise and 4 pound engineer's mallet.

[Pato911]

We should get together as we are both in Houston and tackling similar projects. I just finished getting a single 964/993 condenser in my front fender. The other side has the oil cooler. Some pictures to hopefully help out:





I had to cut the fog light bracket to get the clearance to the tire. I added some shrouds, a support/ shield underneath and a support to the headlight bucket on top. I also made the little shield to direct the air at the fog light opening to the condenser.

I removed the rear deck condenser and moved the line that used to go deck condenser > front condenser to compressor > fender condenser. I then bought a new hose from www.coldhose.com to go from the front condenser to the fender condenser. All else remained the same. I have a leak I am chasing now so I haven't had a chance to charge and run it yet.

[Pato911]

Just saw your comment about the windhield reservoir. I went with a generic bottle in the trunk. Moved the hoses to the passenger side and added a jumper to the pump.

Sorry no photo but I can get one tonight if anyone wants one.

[Pazuzu]

I have the crimping tool

Make some sort of grating over that hole, the find in the condenser are too thin to survive a direct hit from something bounding along on 610 and getting sucked in there at 90mph...

Are you using one or more of the mounting holes that the window washer horsecollar bracket was bolted to? They seem like the best way to hang the whole assembly.

[Pato911]

I used one hole that the U-bracket bolted to. You can see the bracket and final connection if you look close at the above.

Good call on the screen. I will fab something up.

[Discseven]

Originally Posted by Pato911

^ Very nice.

Following thread with much interest Mike.

[Duc Hunter]

Good luck! Looks like a great project. My Retro Air system in my 3.2 Carrera will blow air into the low 30's if I want here in HOT and sticky Florida...until the system freezes. Hopefully you both get the same results.

[Pazuzu]

Originally Posted by Pazuzu

No it's not. I did a finite element analysis of the car, this is the optimal place to put the condenser. I did however have to take it and put a 15 degree bend in it to fit deeper in the fenderwell, that was not hard with my bench vise and 4 pound engineer's mallet.

Darnit people, this post was meant to cause a ruckus! Why did no one step in and explain to me how bending a condenser with a mallet might not be advisable???

[wwest]

Originally Posted by Pazuzu

Darnit people, this post was meant to cause a ruckus! Why did no one step in and explain to me how bending a condenser with a mallet might not be advisable???

Some (most?) of us decided that we didn't need one leg longer than the other..??

[Discseven]

Originally Posted by Pazuzu

Darnit people, this post was meant to cause a ruckus! Why did no one step in and explain to me how bending a condenser with a mallet might not be advisable???

All is not lost yet Mike. Post a picture of the bend.

[Rawknees'Turbo]

Originally Posted by Pazuzu

Darnit people, this post was meant to cause a ruckus! Why did no one step in and explain to me how bending a condenser with a mallet might not be advisable???

Did the mallet cause gas reversal to occur?!?!