W116 450SEL AC conversion to R134

[bnunes39]

Hi,I have a W116 450SEL Japan specs, the AC performance in very, bad, I have read about the R12 if replaced with R134a will cause this issue, I need help as to type of Compressor,  drier, condenser, need to be replaced to get the AC to bring a good enough cooling so as the car can be driven , temperature here reach 47C during summer and go even higher, I got another A6 used, replaced the condenser parellel which I got from a W211 and modified to fit, replaced the expansion valve, but no improvement,  please can someone advice .
Thank you.
Sebastian.

[daantjie]

Maybe just for clarification do you currently run R12 or R134a?
From my limited experience R12 does cool better than R134a. 
You need to read and tell us the temperature at the vents you are seeing as a baseline as stating it's "very bad" for your situation might be quite acceptable to others of course.

[ptashek]

At those ambient temperatures the system will likely struggle no matter what.

I don't have AC in my W116, but one of the W124s has a factory R134a system. It's not really that much different in construction.

It takes a long time to cool down the cabin at >30°C ambient. Several minutes on full blast.

Can't remember the exact vent temps, somewhere around 4-7°C.

I'd probably start with checking those, and then system pressure low and high-side.