AC pressure...

[Autocross7]

Well it is time to check the AC system as summer is upon me... and I was looking through some notes on the AC system and I ran accross info stating that the pressure should be about 2.2lbs.

I naturally asume this is for the 'low' side, but I find that number to a bit low? The notes do not say, but is the 2.2 lbs measured when the car and AC are not running?

All of my other cars are to have a charged pressure of 24 to 40 lbs! so 2.2 seems really low. However, the 37 lbs I run the MX-5 and the RX-7 is measured with the AC system running full.

Thoughts please?
Drive topless!!!
Cameron

[scoule]

2.2lbs is not the pressure, it's the weight of R134a that the system needs from empty (ie. vac'd out).

Steve

[jk1]

Cameron,

2.2 lbs is the total amount of Freon it's supposed to have in the system not the operating pressure, sorry don't know what that is.

I believe you have to use some kind of conversion chart to relate operating pressure to coolant level but not sure as I'm no a/c tech.



Good luck,
Jim

[kmaier]

Typical pressures tend to vary over a wide margin with R134a systems. Variables such as compressor operating speed, ambient temps (both outside and inside of the car), air flow over the condensors, etc. all affect the high and low pressures of the system.

As a result, you can either evacuate the system and do a fresh charge of the recommended weight of freon or use an accurate thermometer (in the center vent) and add or remove freon to dip the output temp (while closely monitoring the pressures). I use the latter on my car while on the lift and all systems go to simulate worst case "stop 'n go" traffic. You can usually get the temp down to the mid 40's (F).

Regards, KM
2000 V8

[bojangles]

Did we all learn that pounds is a force.. and Pressure is a force divied by an area? What grade was that lesson in?

ie pressure is pounds per square inch.. psi.?

I am happy to use the message board for technical help but come on now.... hehehe

Just disturbing the peace a bit.. no offence ...

[Autocross7]

Ahhhh...
That would bring me to the real problem with these notes I have dug up... they are not very technical... and I have trouble paying attention!

My heads is doing psi... the notes seem to do both? You are correct - no offence taken
God love em'
... Only an engineer would care about weight vs pressure - hahaha...

Thank you all for the replys! I set my system at 35 psi and she is blowing cold... vent location has got my right knee nice and chilled! One of the many quirky things I love about this car...

Drive topless!!!
Cameron

[deecee]

Question...Has anyone retro'd an upgraded Blower Unit into a Guigaro Esprit?

The Shop Vac Air Vent Line really Suck and I was wondering if there was a way to move a Higher Volume of Air.

Living in the Desert, there is no such thing as Too Cold of an AC Unit.


Regards,
Daryl