Automotive Air Conditioning Information Forum (Archives)

Mr_Squishy on Sat July 10, 2010 2:39 PM

Year: 1986
Make: BMW
Model: 635CSi
Engine Size: 3.5L
Refrigerant Type: R134a
Ambient Temp: 93
Pressure Low: 27
Pressure High: 295
Country of Origin: United States

This is a new conversion to R134a. Just finished charging and center vent temp is 54 degrees at idle. It drops to 52 degrees around 1500-2000 RPM.
The system has a new SD508, a new PH condenser, new evaporator, expansion valve, drier, and all new hoses. Vacuumed for over an hour to around 29".

It is a relatively low humidity day here - only 70% - usually we are 90%+. I'm basically seeing a 40 drop from ambient. Is this about the best I should expect with the R134a?

Thanks.

Sixseas on Sat July 10, 2010 3:05 PM

A 40 degree drop from ambient it pretty respectable I think, dont think you will get more than that. I did convert a conversion van from R12 to R134 vent temp did seem to fluctuate more with RPM than non converted systems. As I recall the best I could do was 38 vent temp at 75 to 80 degree ambient. It was more than adequate went through Las Vegas at 119 the year they had the rains and humidity kept cab temp very low at high speeds but vent temp would rise some when I pulled off freeway. Dont know if it helps the other day checked my R 134a factory systems in Toyota,XFI and dual AC in van all vent temps at 92 were 55 at idle speed. All seem to keep the cars cool in heat and high humidity.