Automotive Air Conditioning Information Forum

I have a 1986 33 foot motorhome with a 454 and the compressor is an R4. I would like to add a second evaporator midway in the coach for additional cooling. I would like it to work as one system whenever my front ac is turned on.
1: Will I need two orfice tubes or can I run both evaporators in series using just one ?
2: Would a larger condenser be necessary ?
3: Additionally, would a Sanden compressor be a better choice for overall performance regardless of any system mods ?
thank you

The R4 compressor is great for your application. It is one of the biggest compressors ever built for cars. I would T the high pressure liquid line and run one orifice tube per evap.

gm76 wrote: ↑Fri Jun 04, 2021 8:28 pm 1: ......can I run both evaporators in series ....?

Not in series; refrigerant vaporizes in an evaporator, and needs to be a liquid entering an evaporator. So an additional evaporator would need to be in parallel.

Rear systems will normally be an expansion valve design and have a drier, for the rear unit.

Thanks (V8Power) for giving me confidence in the R4 and (Cusser) for reminding me of the difference between series and parallel. And (Tim) I don't know if it would be ok to have two different types of expansion valves in the same system, or is that how they are normally set up, that I don't know ??

I hope that the illustration I included seems like it would work in your opinions. thank you !!!

Like Tim said, the rear normally has the TXV when you have 2 evaps off one compr.

A little history: This is a 1993 Chevy engine and ac system that I merged into the 1986 motorhome. I removed the original drier and TXV from the stock system and plumbed in an accumulator and orfice tube. The system has been working ok. Now that I want to add a rear ac system, I'm a little confused about the combination of components needed to make everything work.
1: Is it ok to leave the front system with an orifice tube as is, and add the second evap with the TXV ??
OR
2: Can I build the system with (two) orifice tubes not using a TXV ??
thank you

No offense but I am gonna let others jump in here and take over. The questions that keep coming are the same

Some just want you to tell them what they want to hear.

The last attempt to explain. Otherwise, it just gets repetitive.

This last attempt to explain is just the diagram I needed to go forward with my project. I thank you for that. I understand that the rear is normally a TXV. I was just curious as to why two orifice tubes in the system wouldn't have the same results. thank you