[Squidward]

The most important thing is that you go less than factory to start with, and 80% was a good place to start. With the engine turning at about 1500 rpm and ac on max, your high side should be roughly 2.5 times the ambient temp (i.e. 80 degrees = 200#).

Another rough check on charge that doesn't apply to ALL systems is to see what your static pressure is when ac is NOT running. Your static pressure should be close to the value for ambient temp (80 degrees should be around 80-ish pounds).

Of course, you'll need working gauges to check this. I suspect you are still undercharged a little. Unless you are driving with the windows down in AZ, your clutch should cycle infrequently. Did you put your cans in a bucket of hot water while charging? That's the only way I've found to come close to emptying the cans after the first one that charges into a vacuum.

[Rob B]

Originally Posted by Squidward

The most important thing is that you go less than factory to start with, and 80% was a good place to start. With the engine turning at about 1500 rpm and ac on max, your high side should be roughly 2.5 times the ambient temp (i.e. 80 degrees = 200#).

Another rough check on charge that doesn't apply to ALL systems is to see what your static pressure is when ac is NOT running. Your static pressure should be close to the value for ambient temp (80 degrees should be around 80-ish pounds).

Of course, you'll need working gauges to check this. I suspect you are still undercharged a little. Unless you are driving with the windows down in AZ, your clutch should cycle infrequently. Did you put your cans in a bucket of hot water while charging? That's the only way I've found to come close to emptying the cans after the first one that charges into a vacuum.

I figured that I'm a little under charged right now. My high side guage isn't even working and the low side appears to be about 10-15psi off(guage needle won't rest on zero anymore). I suspect they got knocked off the hook they were hanging on in the garage. When I drove it, it seemed the compressor was cycling a little more than it should. Since I only have 36 ounces in, I'm going to charge it with one more can which brings it to a total of 48, well below the 68 ounces called for from the factory for R12. With a 20% conversion rate for 134, that would put me in the 54ounce range for a full charge.