classicretrofit Posted January 20, 2024 Posted January 20, 2024 Classic Retrofit recommends our 175A unit, the main advantage being the high idle output (75A) which will enable the system to run full time in traffic. Updating the alternator also requires that the wiring can take the extra current. The wire from the alternator to the starter solenoid must be uprated to 170A 25mm2 wire along with the alternator ground to the engine case. We provide the cable set with all our uprated units. If you have a 964 or 993 based engine you have a 115A alternator but it still requires you to check the wiring is up to spec. E.g. No good having a 115A alternator with a 1974 wiring harness! We also offer a 240A Alternator for 964 and 993 engines. This produces over 100A at idle compared to the 115A which only makes 40A. Check out our alternators here. *The minimum specification alternator to run the system is 90A from the 3.2 Carrera but this is only recommended for cooler climates. Earth Straps It is strongly advised to remove and replace both the battery and transmission earth straps. The studs and landing surface of the earth point should be cleaned until shiny. It is important that the earth strap lug sits flat on the landing surface so that maximum contact area is achieved. The same is true for attaching the compressor earth. Batteries The kit has been tested with standard batteries typically 75Ah. The battery must be in good order. The A/C will use some battery reserve at idle. If you have a lesser rated battery, you run the risk of depleting it sooner but this is negated by having a high output alternator. Settings can be changed within the A/C ECU to guard against this at the detriment to A/C performance at low engine RPM. Please contact us regarding battery spec. With our high output 175A alternator we have run smaller race batteries with success (e.g. Odyssey PC925 which is 28Ah)
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