134a A/C pressure specs?

NO!! R134a pressures will NOT be the same as R12 pressures. Also the 'correct' pressure reading varies with temperature.

It's been 4-5 years since I've done a 308 A/C system & I don't have my reference docs available right now. However, here are some old fchat threads & links that may help:

R134a & R12 static pressure chart
http://www.aircondition.com/dsmobileac/static.html

Questions when I was doing my 1st recharge:
http://www.ferrarichat.com/discus/messages/256120/105688.html
My understanding of static pressure was right.

Static pressure is mostly useful to determine if you have either of these problems:
1. Low static pressure for a given temp: No liquid in the system
2. High static pressure for a given temp: You have air or humidity conttributing the excess pressure.

Dynamic pressure is used to determine how well the system is cooling.

IIRC, Ed Gault (professional Technician, had a 308 in those days) has rules of thumb that I found to be generally good.

These threads have some more info:
http://www.ferrarichat.com/discus/messages/256120/2120.html
http://www.ferrarichat.com/discus/messages/256120/125817.html


I also found that it's best to slightly underfill by a little bit. If you overfill R134a you run a very high risk of blowing a compressor gasket or seal as the high side pressures head thru the roof when the system is over-filled.

About 8 years ago, when my son was in 2 year Tech school I read & eventually ended up with his A/C course textbook. It was really great, covered all aspects. Should have got my license while I had everything fresh in my mind. Now I need to go back & study up again. At least I highlighted the most significant stuff in the book.

I hope this helps.

 

Here is a little studing for you to do. The internet is your friend. http://www.aircondition.com/tech/questions/82/

 

I have to say that I've pretty much come over to the view that if you have an oem system, you need to charge it with either R12 or with a refrigerant such as Duracool. 134 is considerably less efficient than R12 and even more inefficient compared to Duracool. The oem system is marginal at best and does not have the ability to make up for that loss of efficiency.

If you have installed a modern, more efficient/larger condenser and more evaporator blower capacity, then 134 is fine, as it is on any modern car ac system.

Duracool is cheap and is actually even more efficient than R12 BUT there are legal and service issues re using it and many shops won't install it or evacuate it. If you do the work yourself it's not an issue.

 

The latest issue, June '11, of Road and Track has an article about A/C starting on page 120 "Keeping Kewl." The last section of the article is titled "What's the deal with R-12 in older car." The article has some interesting information. Basically, R-134a will be a compromise in a R-12 system.

Also, I took the EPA 609 refrigerant test on the ASE website last week. "ASE Refrigerant Recovery and Recycling Review and Quiz." 30 multiple choice questions with the answers for the questions available on a drop down page of the test. You have to get 24 right to pass, but it is basically open book, answers provided, with no time limit. The ASE online test costs $15.00 and assuming you will pass it, you can buy R-12 refrigerant. You can print out a temporary certificate from the test results page.

DRG

 

You guys are so lucky in the US.Here down under,its easier to bring in Heroin than R-12

 

I'm not convinced you're significantly under-charged. What you may be seeing is simple thermal lag effect due to the car's mass taking time to reach air temp, meanwhile the air temp has increased.

The best static reading is the overnight one & it looks good.

Since the system is also blowing cold, I'd stop messing with it & enjoy it!

I agree, pulling those lower vents makes a huge comfort difference!