993 Condenser in a 911...Anyone Complete This???

[1974carrera]

While completing my plan to upgrade the A/C in my '74 with more condenser capacity another Pelican shared the idea of putting a 993 condenser in his 911...thanks Mark 74 Carrera! A search turned up a little information about doing this, like this picture by ruf-porsche at the end of this thread:

993 condenser

Has anyone completed this project? It seems like some folks may have used just the 993 condenser in the left front fender and no other condensers, but I really don't know. Fabricating a mounting bracket would seem like the hardest part, and I don't think that would be much of an obstacle. It would take the place of the washer fluid bottle in the left front, like in the picture belwo.

Any advice, experience, pictures on this?
Thanks

[1974carrera]

[Joeaksa]

Patrick Motorsports here in Phoenix has been doing this for a long time and they really like it. They say it works very well and is not that expensive if you find the parts in a wrecking yard.

Does away with the problems of a belly condensor and offsets some of the weight of the engine in back.

Joe A

[mark 74 carrera]

Bob

Here's a picture of mine. It is interesting as it appears to be mounted reverse of the one shown in the thread you attached.

Mark

[1974carrera]

Mark, you have the most interesing installation of a 993 condenser I have seen, not that I've been able to find many. The Cu lines seem like a good idea. I'm wondering if your fan pushes or pulls?

Joe, I agree with you about the advantages. And the cost seems reasonable too since the price of a new 993 condenser is about the same as some of the aftermarket condensers available for upgrading the stock 911 condensers.

I guess I could use the stock 993 condenser fan assembly, but after seeing Marks installation it looks like a different fan assembly might be more compact...and maybe less expensive than the Porsche fan. I still haven't found much firsthand info on completed installations other than wjhat Mark has but I have read several references that indicate using only this one condenser is sufficient, and that would be an advantage too.

Any more DIY experience out there with this? If anyone has a scrap 993 condenser for a reasonable price I'd like to try fabricating a mount and mocking up an installation to see if I like it.

[Dennis Kalma]

I haven't gotten that far in my project, but the plan is to fit a 993 condenser in my '89. I did a bunch of fitting a while back, but the result was that I am going to cut into the battery bulge, put in flat metal and then mount the condenser much like the C2 or 993. I figured that I just wouldn't get the airflow I wanted to get it properly cool and it wouldn't "look" right.

There was a thread a while back that went through some of this.....I don't have the time to find it right now, but it should be easy to locate....

Dennis

[mark 74 carrera]

My fan pulls.

The fan is not a porsche product but aftermarket. Matt Haslett at TPWS here in Austin custom fabricated the mounting bracket. He also fabricated brackets for the fan so that once installed he could remove the fan for replacement with out removing the condenser.

The Cu lines were also his brain child. Their appearance takes a little getting used to but they will not leak over time like rubber hoses.

[1974carrera]

Dennis, thanks for your comments. Can you expand on what you saw with trial fitting that made you think about cutting down the battery bulge? From the few installation pics I've seen it looks like the condenser can fit in the left front 911 fender without any cutting, similar to way it is oriented in a 993 left front fender...as long as you remove the washer fluid container. I also found this thread when I searched and while it is very interesting it still doesn't seem to deal with a finished installation and whether the 993 condenser alone is really adequate. I wonder if a 993 uses just this one condenser?

Mark, I appreciate the pictures. It sure looks like Matt did a really nice job on yours...and that's what a practical idea to fab up the brackets so you can remove the fan separately if you need to.

[Dennis Kalma]

993 uses just the one condenser, so it ought to work in this application as well. The issue as I saw it was not so much that you could not fit the fan in, just there would be no decent flow for the air getting out. The C2 has the condenser more or less parallel withe the direction of travel, if I recall, it angles slightly outward. It also has the built in air flow from the valence and out into the front fender well, allegedly the flow helped reduce the drag around the front wheel (some tiny reduction in Cd).

I am nervous that if I do not provide a good enough air exit, the flow through the condenser will be too low and hence not enough cooling. If one does the math, the evaporator in the pre-'89 cars has about 214 cubic inches of volume, the C2/993 condenser has about 232 cubic inches of volume. Vintage Air suggests that the condenser should be about 25% larger in volume than the evaporator, so you can see that it is on the small side to begin with (s/b about 290 cu. in to be "right). Add in some lousy air flow, use R134a (worse refrigerant than R12, deduct a bit for good condenser design (serpentine flat tube) and voila...warm where cool ought to be.

As She Who MUST Be Obeyed has said that cool air is a VERY GOOD THING, following the rule of the infinite standard of care, I am cutting out the inner fender to make sure it all works to perfection. I know it would be cheaper and easier to replace SWMBO with a 26 y.o. bimbo, after 30 years of wedded deadlock the ol' girl is sort of growing on me.

I will post pic's as my glacial speed of development oozes forward..

Dennis

[Jim Sims]

"The Cu lines were also his brain child. Their appearance takes a little getting used to but they will not leak over time like rubber hoses."

There is a reason why OEM and after market vehicle A/C systems use aluminum, steel or "rubber/plastic" hose for the refrigerant lines and not copper. Copper lines will leak once they crack from vibration work hardening. Standard copper tubing alloys including coiled copper refrigerant tubing are not used in vehicular service due to poor fatigue resistance. There is a special copper iron alloy developed for brake lines but that is a very different material than the typical copper tube one finds at the plumbing or A/C supply store.

[mark 74 carrera]

Jim,

How long do you think I will have with the regular Cu lines? Is it months or years?

Mark

[Jim Sims]

Hard to predict as it depends on many factors: how hard the line was to begin with, how much it was bent and worked in the process of installation and mounting the fittings (this hardens it further), plus the spacing and tightness/damping of the mounting clamps. The work hardening that leads to cracking and failure is caused by vibration which is a function of how many hours the car and A/C are operated plus road conditions, wheel balance, engine balance, a/c compressor pulsations, etc. If one is very unlucky, a section of the line can go into resonance (think buzzing) with one of the mechanical vibrations the car produces and fatigue rather quickly. I will venture a guess (and that's all it is, given the many factors) of six months to a year before a leak occurs. However it's not a safety related system like brake lines (in the which the use of common copper tubing is such bad practice that it's illegal) so if it cracks and leaks you can have the sections replaced by hose - get the hose assemblies made using the significantly smaller (diameter is reduced by around 40%) reduced barrier hose. Such assemblies will not be much bigger in diameter that the copper tube currently installed. Another consideration is that the rigid copper lines may also cause the fittings of the condensers to fail due to the transmission of vibrations and other loads into them. Cheers, Jim

[Dennis Kalma]

I bought the aluminium C2 lines, I am hoping that the fittings are just silver soldered on....idea is that I take the fittings off, reshape the lines the little bits that are needed and then resolder the fittings on to the aluminium....again I am assuming silver solder.

Anyone really know what they use? They are clearly not welded or crimped.....

There are a few questions I have like exactly how I am going to get refrigerant to the evaporator, but that will be done when the car is at the tub stage and everything else is off. I also want to minimize the amount of hose I use.....not sure why....just feels right.

Dennis

[1974carrera]

Dennis , thank you for your thoughts . I guess I need to find a 993 to confirm but I seem to recall that they use a fender liner in the front wheel well and the condenser is between the liner and front valance...I'm curious how that area is ventilated.

Jim could you comment on the idea of using the 993 condenser? I'm thinking of that in conjunction with the normal 911 front condenser and eliminating the rear decklid condenser. It seems like it would be good to lose that heat source and weight in the rear and I like the ideao of not having to hang that condenser and lines back on my ducktail again.

[Dennis Kalma]

Yes, there is a fender liner. Not sure if it is for protection of the parts or airflow management. I was going to build a louvered panel like that on the passenger side oil cooler...mainly for rock protection and keeping the mud out of the fan.

In terms of liner, I think they essentially sealed the area, as there is a rubber seal around the whole condenser assembly. I think they had ram air flow coming from the valence with its only exit being through the condenser/fan assembly. IMHO it is the way they manage to have a slightly undersized condenser and still have good cooling.

Dennis

[Joeaksa]

JR in Phoenix has soldered copper lines on his A/C and last I heard they had lasted several years with no issue. Will try to contact him and see if he has had any problems.

Joe

[Jim Sims]

"Jim could you comment on the idea of using the 993 condenser? I'm thinking of that in conjunction with the normal 911 front condenser and eliminating the rear deck lid condenser. It seems like it would be good to lose that heat source and weight in the rear and I like the idea of not having to hang that condenser and lines back on my ducktail again."

I do not have any direct experience with this modification and although the 993 is a more modern condenser one has to get cool air through it for it to work (as as been stated already in this thread). Effectiveness in an earlier car will depend on what arrangements are made for air to pass through the condenser. I would certainly have the condenser fan switch on whenever the compressor clutch was engaged or switch it though the intermediate pressure contacts of a trinary pressure switch. Having the front valence condenser will help and if you find you are lacking condensing capability you could upgrade it to a more modern, thicker unit available from a aftermarket vendor.

[Jim Sims]

"has soldered copper lines on his A/C"

It's hard to tell from the images but the fittings on Mark's copper tube refrigerant lines appear to be flared not soldered or brazed.

[mark 74 carrera]

Jim,

You are correct. They are a mechanical connection. BTW, I spoke with my mechanic about the potential for leaks due to the vibrations and hardening of the Cu lines when bending to form.

He said he has minimized vibrations by utilizing a section rubber hose on both the low and high pressure lines at the engine/compressor interaction.

He said "They will not leak until they fail and then we will replace them with rubber if we need to." I am in for the experiment.

Signed fingers crossed, Mark

[dralph12]

Mark
The 993 setup U have is Sweet!
I was reading the thread
It still blowing 30 D. vent temps?
Whats contact info. for Matt Haslett, TPWS n' Austin .
I want to see if I can buy the custom fabricated mounting bracket, 933 Condenser, and fan.