Performance & Hotrod Business - May '15

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May 2015 n Performance & Hotrod Business n 59 Camaro and Pontiac Firebird with the LS1 engine," said Mike Stasko. "Our 4511 series fit the 1993-'97 Chevrolet Camaro and Impala/Caprice, and 1993-'97 Pontiac Firebird with the LT1 engine." Tuff Stuff, which specializes in plated and polished products for hot rods and custom cars, also offers a line of Sanden universal and peanut-style compressors. Remember the Radiator Most folks, we're told, readily under- stand that an engine that makes more horsepower also makes more heat, and may require extensive upgrades to a vehi- cle's cooling system. According to our con- tacts for this story, however, fewer people seem to realize that adding air condition- ing taxes existing engine cooling as well. "A lot of people don't realize that add- ing air conditioning to a vehicle will raise the temperature of the engine when the A/C is running," said Schlottman. "They may need to replace their mechanical fan with an electric fan that is actually going to keep the temperature down." Old Dog usually steers its A/C customers toward a larger and more modern radiator as well. Modern aluminum radiators—like mod- ern aluminum condensers—dissipate heat quicker than older steel units, aided by larger cores, with parallel rather than serpentine flow. "And remember," Carberry remarked, "without adequate airflow, a radiator is just a reservoir for hot water. In general, the coolant transfers heat to the radia- tor tubes, the tubes transfer heat to the fins, and movement of air through the fins removes heat from the radiator. You must allow air to pass efficiently through the radiator and out." And while on the subject of radiators, Carberry reminded us that anti-freeze not only lowers the freezing temperature of water, but also raises its boiling point. "So the proper mix is still 50 percent anti-freeze to 50 percent water. Use dis- tilled water or pre-mix it with anti-freeze. Proper maintenance—that is, flushing and changing coolant—will extend the life of the system." If the car has an engine-driven fan, a fan shroud is a must. "An unshrouded fan only moves air through the portion of the radiator equal to the surface of the fan," Carberry continued. "A shroud also dramatically improves the efficiency of the fan," increasing airflow by as much as 100 percent. "An auxiliary electric pusher fan mounted to the grille side of the radiator will always improve the performance of an A/C system, and keep the engine cooler," Carberry continued. "It should be con- trolled by a pressure switch that turns it on only as needed, as it does not need to be on when the vehicle is in motion above 20 mph. We recommend installing a trinary switch to protect the compressor from too high or too low pressure, and for engaging the electric fan as needed." Pavelec and Schlottman added that customers are often confused by the dif- ference between a trinary switch and the old-style binaries. A binary switch shuts off to protect the compressor if system pres- sure runs too low or too high (hence, binary); a trinary adds the third option of switching on an auxiliary fan or fans to reduce system tem- perature, and therefore pressure. That may be just enough to keep the cool air flowing on a hot day in heavy traffic. If refrigerant pressure continues to rise dangerously, of course, the trinary switch shuts down the system to save the compressor. Carberry added that if installing an auxiliary fan is not practical, then the pri- mary electric fan should be controlled by the trinary switch as well as by engine cool- ant temperature. So a binary should only be used in a vehicle running a mechanical fan only. None of this will help much if there's no way for hot air to escape from under the hood. Carberry noted that it's also a good idea to seal and insulate the cabin area, including the cowl above the evaporator. Finally, Carberry reminded us that selling and installing aftermarket air conditioning helps promote the sale of additional parts and services, including "improved radiators, and electric fan and shroud assemblies. "It also provides the opportunity to look over the entire car and make addi- tional sales. One customer came in for A/C work, but also asked us to determine why his engine was running rough. We found the engine had no compression in two cyl- inders—and what started as an A/C repair turned into an engine job for us. "After replacing the engine, we got the A/C working just fine." John F. Katz is a freelance automotive journalist and his- torian. He is a regular contribu- tor to Performance & Hotrod Business as well as other auto- motive industry publications. He lives and works in south-central Pennsylvania. An in-dash Vintage Air A/C installation in a 1940 Ford. (Courtesy Bill Carberry, Cap-A-Radiator) Custom brackets allow A/C components to fit the tight spaces inside engine compartments and behind vintage dashes. (Courtesy Tuff Stuff Performance Accessories)

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