Quote:
Originally Posted by schoward
I converted to R134a with a new drier and a new compressor from ICE (Intercontinental Engineering (I think)). I have the kuehl center vent. All else stock. I get 33-35 degrees on fan speed 1 at the dash vent on 80 degree plus days. The shop that did it removed and flushed the condensers and thoroughly flushed the sludge out of the hoses which I think was key. Nine years later the system still does ok. Not quite like a modern car with the airflow but ok for the times in summer where I need it.
I am pleased with the results, but I have seen results vary with work others have had done and sometimes disproportionately to the $ folks dump in. Seems you can get lucky and sometimes not so much. In my opinion it's a little gamble and how much appetite you have for what can be a mini money pit.
|
You make no mention of non-barrier hose leakage with the higher R-134a refrigerant pressures, which leads me to suspect your chosen shop knew enough to install a refrigerant pressure limit switch. The EPA "requires" the switch be added to R-12 legacy systems when converting to R-134a. Either way you might wish to upgrade to a RED DOT trinary pressure switch. Lower high side pressure limit, 325 PSI vs ~400 PSI, plus an extra pressure sensing switch that is typically used to control a condenser cooling fan to keep, or help keep, the high side pressures from becoming so high that through-and-through permeation of the OEM non-barrier hoses results.
In my '88 that third switch element is wired between ground and pin 10(***) of the cabin heat control module. The design of that module is such that a ground suppled to pin 10 will result in activation of the cabin heater blower with consistently low roadspeeds. The effect will be more than doubling of the cooling air flowing through the rear deck lid condenser.
*** In parallel with the engine oil temperature senser. The factory design use of this circuit is to provide addition engine exhaust manifold cooling when/if the oil temperature begins to due to the lack of sufficient engine cooling airflow in say, stop and go rush hour traffic.
Your '81 doesn't have the module so you might want to run the cabin heat blower anytime the trinary switch's extra element dictates. The alternative is to wire the switch between a switched 12 volt source and the positive input to the cabin heat blower.
Even with all that there remains a potential for excessive high side pressure post engine shut down resulting in non-barrier hose leakage.
You can lower that potential, possibility, via using the extra pressure switch to provide "after-run" cooling of the rear lid condenser. Either use a 10-15
minute TDR to extend the 12 volt source availiability, or simply wire the extra switch to an unswitched 12 volt source and monitor the battery condition for long enough to verify that there is not enough after-run time period required to compromise the battery's subsequent engine starting ability,