[Supras] EGR operation

[berniek at technicaldevelop.com]

Dear Craig and list:


    Yes, I am aware that the EGR is open off idle, and that at 15 MPH 
used for the load emission test it would be open.  What I don't 
understand is that in most applications, the throttle body port commonly 
used for EGR signal pickoff is large enough that there is a small degree 
of vacuum modulation as a function of throttle opening and (of course) 
load.  The Supra method appears to be insensitive to throttle opening 
(SOV is either open to the intake manifold or closed), but obviously 
will be sensitive to load.  Any ideas about the "hows and whys" would be 
appreciated.


    Thanks.


    BernieK