Hey I am going to be charging/inspecting my a/c system that was recently converted to R-134A and was wondering if anyone had a GM shop manual that gave the relative high and low pressure settings at ambient temperatures that i should fall into to know the perfomance of the system while, durring and after charging.

My setup is a 305 non cc controlled carb v-belt setup with I think what youd refer to as a D2 Compressor that came on all the earlier model V8 Camaros.

Thanx for any help, couldn't find anything on the search

 

 

Hey Nina, thanks alot for the quick response! Appreciate it, Peace!

 

That seems undercharged. How do you get 180 psi on the high side? My car idling with the A/C on runs 35 psi (low) and 235 psi (high).

At 180 psi, the passenger fan wouldn't even turn on.

For R-134a cars, I'd say 28-30 psi low and 230 psi high while idling would be about right.

 

Hey Fleming thanks for your input. if we dont have any "concrete" numbers thats cool. the low side there seems to be some agreement on so thats great and the high side, well....these give me a baseline for what I should be looking for when testing at 2,000 RPMS

 

Since I teach climate control guess I could tell how to get some reliable pressure numbers you
Just need to do a little math

First using a stem type thermometer get the ambient air temp 2" in front of condenser engine at 1500- 1700 rpm take this number and multiply by 2.5 this will give you high side pressure numbers readings + or - 20 psi of this number would be within spec

Low side should be between 20- 45 psi

 

Thank you 92 I appreciate all the input will definately use this knowledge upcoming with my a/c. Is this something that is generally used automotive wise or climate controlled wise since you teach it? That way its some piece of knowledge I can hold onto. A/c isn't my strong point yet!

 

Here's a handwritten piece I did just for the heck of it. The temp-pressures you see here are a bit different from traditional temp-pressure charts on the net. I've added 10°F to the low side numbers (everything 50°F and colder)

So my car with R-406a at idle was at 35 psi (aprox 42°F duct temp) and 140° condenser temps (235 psi). That was a cold start (at 90ish degrees outside)

(Ignore the stuff in the middle of the page. I was just seeing what temp 175 psi was with all the different refrigerants)