Low temp thermostat

[CSH-HQ]

Properly tuned (note, the phrasing), an engine will live as long or longer, 
and use less fuel in open loop, IMHO.
  I have to do some more actual work on this but intial reporting, from 
programming 101 seem to support this.
  Closed loop is for maintaining a 14.7:1 AFR.  Which assumes several things
ie the formula for the fuel at hand is close to what is expected of it.
To keep the Catalytic converter hot enough to function.  There is more 
detail in the archives about the rich len cycling of the AFR to keep the 
converter working.
  Open loop or closed loop is a matter of tuner's preference.  Or for EPA
testing.  I'm not too sure where we'd be since I don't have a gas analyzer,
but I bet ya it could be clean enough for most applications.
  Higher operting temps. make radiator cooling an easy function, try 165 for 
on temp., and 205 on a warm day.  THe on time for my car went from almost 
never to always on.
  Grumpy  

>I thought that the object of game was to keep the thermostat in the closed 
>loop mode. It should only be in open loop during initial warm-up. The ECM 
>can try to change engine operation during upper engine temperature 
>excursions, but it can not change the outside temperature or the fact that 
>you are stuck in traffic. In the Suburban 1227165 TPI project, I plan to 
>change from a engine driven cooling fan to twin electric cooling units 
>which I can control via the ECM. With air conditioning you could/will add 
>heat to radiator because of the airflow path, the ECM knows head pressure 
>and engine temp so it could short cycle the compressor, and add additional 
>cooling to lower AC head pressure.
>
>So I think the selection of a thermostat operating temp and strategies of 
>how to keep the thermostat in a closed loop operation is a very important 
>part of the gm ECM discussion. I would like to hear more!
>
>David
>