a/c low side pressure questions - not broken, just asking

[retiredat44]

This with the same model car (1989 Corolla SR5 1.6, carb, 5-spd stick), and/or the same a/c system that the 1989 Corolla uses, but with R134a Refrigerant (has been converted a while back from R12), what is your lowside port pressure ?

I am at 30 PSI at idle (between 650 and 800 rpm). I am less interested at higher rpm as I have no problem with that. I am just questoning setting it for 30 or 35 psi at idle). (FYI at 2,000 rpm the low side drops to 15 psi or lower) I recently replaced my Shrader valves on both the high and low side ports, due to a very slow leak. I am thinking about maybe adding a touch more. as the temps have increaed slightly with hotter weather. myabe moving it to 35 PSI high -low side PSI. But some cars have even higher low side pressures as high as 50 psi, at idle.

note, A/C works really nice) but again, checking to compare that others with a Corolla low side high pressure reading is at idle).

Thanx..

[Flashmn]

I'd check it, but I lack the gauges to do so...besides I'm pretty sure my system is empty ATM. My compressor is leaking from between the clutch and housing, crap... gotta see if I can replace the axle seal.

On another note, I was under the impression it was measured in grams how much cooling agent you have in there, rather than pressure. Volvo takes around 750grams, and heres the problem if you add stuff if its leaked out, how are you going to know how much you have in there. So for the volvo, the only way to fill up the system is to first empty it and then add stuff.

[retiredat44]

yes, some go by weight... other don't... plus it's easy if you are stsrting from a completely empty clean system, but I wasn't.. so I am going by both pressure and temperature.

[Flashmn]

True, alot of the "better" aircon places here suck the system dry first, then they basically start from a "blank table"....I wonder if those Ebay freon-adding kits are worth anything, got any experience in them?