THE SHOP

Performance & Hotrod Business - May '15

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operated, or have servo motors opening and closing the air-control doors." More importantly, perhaps, "electronic controls make the installation plug-and-play. And it's the difference between a switch and a rheostat. The thing about vacuum, it's either on or off, so your doors are either open or shut. Electronic systems are more tweak-able, because they give you more control over how you operate your doors." One potential issue, which has turned out to not be an issue at all, is the unavail- ability of R12 refrigerant (a.k.a. Freon-12), which was the industry standard until it was largely banned by Federal environ- mental regulations in 1994. At the time, many professional prognosticators pre- dicted the end of air conditioning, period. Twenty years later, we found little complaint with R12's successor, the more environmentally friendly R134a. "R12 will start working quicker," Farr noted. "It nor- mally runs at a lower head pressure, and it sure doesn't demand as much airflow through the condenser. But with 134a, if you have a good condenser, and keep air flowing across it, it will perform very well for you." Farr added that the latest generation of condensers "are all aluminum, and ours are built with a multi-pass configuration, which means instead of going in one side and out the other, the refrigerant makes two to four passes through the coils. And they are built with 14 fins per inch, where some of our competitors use 18 or even 19. Fourteen per inch still allows good airflow through the condenser without starving the radiator." Schlottman noted how "the newest Sanden compressors are even more com- pact" than in the days of R12. In fact, "everything is a lot smaller" now. One "critical" difference, according to Pavelec, is the type of oil required to lubricate the compressor: R12 required mineral oil, whereas 134a systems use PEG oil (for PolyEthylene Glycol, derived from castor oil). A few of our experts have even mas- saged older A/C systems engineered for R12 to work fairly well on 134a. Old Dog recently converted an Impala from the early 1970s to run on 134a. "He's still Under-hood view of a '57 Chevy with Vintage Air FrontRunner accessory drive kit. (Courtesy Bill Carberry, Cap-A-Radiator) using his original heat and air with a new compressor and a new condenser," said Schlottman, "but the fittings and expan- sion valve are changed over to accommo- date 134a." "We can do a lot of specialty work," added Farr, "maybe even convert an older system to a modern accumulator-and-ori- fice type, that will work a lot better with 134a. The bottom line is still all about getting enough airflow through the con- denser, to keep head pressure down." Cap-A-Radiator, said Carberry, is also "experienced with getting original A/C systems back into working order, while maintaining as much originality as pos- sible if that is what the customer wants. We frequently do install upgrades in '70s and '80s cars that were built with A/C from the factory. Better compressors and condens- ers offset the slight performance drop of converting to 134a. Not too many people mind using 134a as long as it blows cold when done." In any case, Farr added, the proven performance of 134a in today's OEM cars and trucks should convince any remaining doubters. Where to Put the Air Also for those who want to keep a factory-authentic look, Old Air has "repli- cated parts from GM, Ford, and Chrysler," Tuff Stuff Performance Accessories offers A/C compressors and components for GM LS and LT engines. (Courtesy Tuff Stuff Performance Accessories) said Farr, "including compressors, dryers, hoses, aluminum lines, and some special fittings; right on down the line to evapora- tors, condensers, switches, vacuum actua- tors, heater valves and heater cores, etc. And if we haven't replicated the parts you need, then we can often rebuild the cus- tomer's older parts, to help them rehabili- tate their system." Cars that didn't come from the fac- tory with air conditioning—and didn't even offer A/C as an option—present their own unique challenges. Fortunately, another major advantage of today's rela- tively compact aftermarket systems is that they fit well in older cars. Generally speaking, the older the car—or truck—the May 2015 n Performance & Hotrod Business n 57

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