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Old 06-16-2014, 02:18 PM   #24 (permalink)
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Nameless - '06 GMC Canyon
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Originally Posted by oil pan 4 View Post
I thought there would be a much wider pressure swing with the R-404a mixture, because of the way refigerants act in a refrigeration system.
If you cooled a tire filled with 100% R-404a down to -20 deg F, the pressure would drop to 31 PSIA, or 16.5 PSI on the tire gauge because some of the R-404a would condense to a liquid.

If the tire is filled with 100% R-404a until the R-404a is a mixture of gas and liquid, then the pressure will be the saturation pressure listed in the refrigerant data sheet. That would be 150 PSIG at 70 deg F and 450 PSIG at 150 deg F.

I would expect gases with larger molecules, such as CO2 and R-404a, to have lower lead rates.
The vacuum gauge plus wheel covers helped increase summer 2015 mileage to 38.5 MPG, while summer 2016 mileage was 38.6 MPG without the wheel covers. Drove 33,021 miles 2016-2018 at 35.00 MPG.
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