Dual AC condensers on w108

[vandor]

The clutch died on my 3 year old AC compressor, so I had to install a new compressor and evac the system. I decided to covert to a more efficient modern condenser. I bought part CN20015XC on a popular website that sells everything, but when it arrived I noticed it was half as thick as the original, so even if it was more efficient, it had much less fin area. So I ordered another one and mounted them back to back. I had custom hoses made to make it all work. I ended having to mount the drier in front, as there was no longer space next to the condenser(s).

I have been experimenting with pressures, but it has not been warm enough to test the system well. It is supposed to be low 90s this weekend, so I will have a chance to test it some more.

[BWhitmore]

Nice work, beautiful car, and great pictures. Thanks for sharing.

[vandor]

Thank you! To anyone that wants to replicate this, the refrigerant has to enter the rear condenser first, thus the hotter refrigerant get cooled by the hotter air that already went through the front condenser. If it's done the other way, there may not be enough temperature difference between the air and the rear condenser to do much heat transfer.

[Squiggle Dog]

That's great! I'll have to do the same thing on a W111 project of mine. I think what would work even better then running the refrigerant through the rear condenser first and then the front condenser second, is to split off the hose into a "Y" so the refrigerant splits off and runs through both condensers at the same time so it acts like a thick condenser.

[vandor]

Yes, that would likely work, but I think finding the right fittings and putting them in that tight space may be a challenge.
In my original plan I wanted hoses with 180 degree fittings, which would have kept the hose runs very short. Well, apparently 180 degree fittings are either non existent or very uncommon, as neither of the 2 AC shops I went to had to or had ever heard of them.

[Squiggle Dog]

I hear you there on obscure hose fittings. I had to find some real oddballs when I did my 1980 W116 300SD. It seemed like every fitting I wanted to use either didn't exist or was almost impossible to find. I was able to fit a single 16X22 parallel-flow condenser in there (the original tube-and-fin one was 16X23), so I felt it was adequate size to use alone. Judging from the fact that the air conditioning is extremely cold even in Phoenix heat, I was correct.

But, a W108 has a narrow radiator opening and a W111 even more so, so doubling up on the condensers as you have done is probably a necessity if you want decent cooling and are running anything other than R-12. I'm pretty sure you'll end up with a good system. The factory air conditioning on the W111 didn't even have an auxiliary fan!

[vandor]

Went for a drive, it was 92F (33C) and party cloudy. On the highway the air out of the vents is 40F (5C), which is about what most modern cars do. At idle it was a few degrees warmer. Will see how it does when it's even warmer.