Quote:
Originally Posted by Porsche944Owner
what is the AAR controlled by? I was under the impression the AAR slowly closes as the car warms up due to the mechanism inside expanding, and therefore would open when the car is cold, with the freezer simulating a cold day. I understand this is quite abit different the ICV of the later cars.
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This is the correct behavior for an early 944. The AAR has a coil of bi-metallic strip connected to a butterfly valve, and a heater. Cold it starts out open. Power to the fuel pump also powers the AAV heater, which causes the bi-metallic coil to slowly close off the airflow. It takes a few minutes to close completely on a very cold day.
The AAV is on page 1 of the schematic, where it is called the Supplementary Air Valve. There is also another supplementary air valve if you have air conditioning, which is electric binary and opens when the compressor clutch is active.