Anyone purchase/install the LMR R-134a conversion kit?

FastDriver said:

I suppose too low a pressure correlates with less coolant mass in the evaporator core, which means that it has less mess to transfer energy into.

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[More] actually, leaving no room for the gas to expand. That expansion is the energy release that causes the cooling effect.

Then we use all that horsepower to compress and turn it back into a liquid / rinse / repeat

I did a Spectra Premium condenser. It fit fine, no issues.

The new condensers are thinner than the older ones, which affects refrigerant capacity slightly. So when you add the required 8-10oz of oil, you'll probably expect to add 38-40 oz of refrigerant vs the original fill of 42 oz.


The 80% charge idea that is commonly thrown around has nothing to do with the process of going from R12 to R134 and more to do with the fact that folks doing this usually overfill on oil when doing retrofits. They add the required R134a oil, but never really get all the old oil out. Oil doesn't compress. So if you overfill on oil, install the new (smaller) condenser you cannot add the full 42 oz or you will pop off the high pressure relief. Hence the 80% rule.

Brand new system? Have a rough idea of how much oil you added? Then really you are only reducing a few oz for the smaller condenser. Charge to 36-38 or so and watch pressures as you creep up a bit to 36-38. Should be using manifold guages to charge as you need to keep an eye on high side.

One of these days I need to put together a Fox-specific write-up on AC. There's some good ones but they miss out on some details.