A/C operating pressure
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Car: 91 RS
Engine: 4 bolt 350, .060 over
Transmission: 700R-4
Axle/Gears: 3.23
A/C operating pressure
Does anyone have a spec for the operating pressure for a '91 A/C system? I'm not sure if I'm low on refrigerant or there is some type of switch problem, either pressure or engagement. The system is now 134 with a March pulley setup and Sanderson compressor. When the clutch engages it blows ice cold air however when I select AC on the control panel it does not turn on every time. This seams to occur mostly when the engine is warm and generally the system engages when the engine is cold or first started. The condenser is a year old.
Thanks
Roy
Thanks
Roy
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Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
The Pressure’s ON ! ! ! ! ! !
When it’s 80° out the high-side should be about 190PSI, and the low-side about 45PSI when the system is running.
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Happy Racing !
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I Didn’t Jump The Start, The Flagman Was Late
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Happy Racing !
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I Didn’t Jump The Start, The Flagman Was Late
#3
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Re: A/C operating pressure
Ensure that your compressor is getting the proper signal from the various controls. I don't recall what type A/C system these are (TXV/Orifice tube) but the compressor will not engage if certain conditions are met. There is a thermal limiting switch on the compressor that will disable the compressor if it is too hot. An in-range failure of this switch may cause the problem you are having. Another issue you could have is water vapor in the A/C if the system was open to the atmosphere for a period of time. The only way to fix this is bringing the system into deep vacuum.
As a general rule, the operating pressure of the high side will be from two to three times the ambient temperature, where the low side will be between 30 and 50 PSI depending on the high side pressure and ambient temperature.
As a general rule, the operating pressure of the high side will be from two to three times the ambient temperature, where the low side will be between 30 and 50 PSI depending on the high side pressure and ambient temperature.
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Car: 91 RS
Engine: 4 bolt 350, .060 over
Transmission: 700R-4
Axle/Gears: 3.23
Re: A/C operating pressure
Cool, I started with a 1984 Belinetta. Thanks for the input, does anyone know where the orifice tube is located?
Thanks again,
Roy
Thanks again,
Roy
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