Re: CPU-controlled '88 ur-Quattro WG?

[glen.powell@smc.com]

  The ur-Quattro's CPU shutdown of the fool pump when overboost is detected
  is unrelated to temperature. However, an actual overboost condition that
  could trigger shutdown could be temperature related. In theory, an engine
  should be able to build more boost at a given RPM when the ambient temp
  is lower. If this additional boost is enough to trigger the overboost
  protection, this could possibly cause the cut-out observed at low temps
  and high boost.

  I disconnected the hoses to the WG on the 5000CSQW to eliminate the
  possibility of the CPU changing the boost level for the purpose of
  testing different WG springs and also for testing of my modification to
  allow external adjustability of the WG, and to set the boost level
  without interference by the CPU. After the "static" boost level was
  adjusted as high as possible without CPU-shutdown (~1.3 Bar) the hoses
  were reconnected.

  On a related note, I often observe what feels like a small loss of power
  as the boost comes up to max, it feels like the CPU might be reducing the
  boost via those WG control hoses, but the "knock" light never comes on. I
  may try disconnecting the WG hoses and testing to see if the perceived
  power loss might be due to the CPU reducing boost.

  -glen